USMLE WORLD STEP 2 CK 3*
(INTERNAL (INTERN AL MEDICINE) MEDICINE ) *Block
BLOCK # 3
93 94 95
Internal Medicine Internal Medicine Internal Medicine
Poisoning Respiratory ID
116 117 118
Internal Medicine Internal Medicine Internal Medicine
ID Preventive Medicine Preventive Medicine
96 97
Internal Medicine Internal Medicine
Rheuatology !e"#nc
119 1
%$Internal Medicine Internal Medicine
Rheuatology &iostatistics
98 99 1%% 1%1
Internal Medicine Internal Medicine Internal Medicine Internal Medicine
'ardiology 'ardiology &iostatistics !e"#nc
1$1 1$$ 1$3 1$4
Internal Medicine Internal Medicine Internal Medicine Internal Medicine
Rheuatology (ndocrinology )enitourinary Rheuatology
1%$ 1%3
Internal Medicine Internal Medicine
)I* (ndocrinology
1$5 1$6
Internal Medicine Internal Medicine
Rheuatology 'ardiology
1%4 1%5 1%6 1%7
Internal Medicine Internal Medicine Internal Medicine Internal Medicine
Respiratory )enitourinary ID +eurology
1$7 1$8 1$9 13%
Internal Medicine Internal Medicine Internal Medicine Internal Medicine
ID Respiratory !e"#nc !epatology
1%8 1%9 11% 111
Internal Medicine Internal Medicine Internal Medicine Internal Medicine
Respiratory Respiratory (lectrolytes ID
131 13$ 133 134
Internal Medicine Internal Medicine Internal Medicine Internal Medicine
)enitourinary (ndocrinology +eurology Respiratory
11$ 113 114 115
Internal Medicine Internal Medicine Internal Medicine Internal Medicine
(+* +eurology Miscellaneous Internal Medicine
135 136 137 138
Internal Medicine Internal Medicine Internal Medicine Internal Medicine
!e"#nc )I* (ndocrinology (ndocrinology
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USMLE WORLD STEP 2 CK 3*
(INTERNAL (INTERN AL MEDICINE) MEDICINE ) *Block
Q NO 93: A 34-ye!-ol" #le $% &!o' o e e#e!e+cy "e,!#e+ (ED) &y $% +e$&o! Te +e$&o! .o'+" e #+ ly$+ o+ e ,oo! &e%$"e + e#,y &ole/ &' e .o!o o &!$+ e &ole %$+ce e 0% $+ '!!y I+ e ED/ e ,$e+ $% co+%c$o'%/ &' $% $+ %e1e!e ,$+ $% o+'e $% 0$e/ +" e1y "!ool$+ o. %l$1 $% +oe" W $% e #o% l$kely c'%e o. $% ,$e+% %y#,o#% A. B. C. D. E.
Anticholinergic poisoning Caustic poisoning TCA poisoning Cyanide poisoning Alcohol intoxication
Explanation: In this case, the important clues to the diagnosis of caustic poisoning are: (! conscious patient, ("! #hite tongue, and ($! hea%y sali%ation. &urthermore, mouth 'urns, drooling of sali%a and dysphagia are classic indicators of caustic acid and alali ingestion. The patient is often conscious, 'ut in se%ere pain. )e%ere esophageal and stomach ulceration may occur, and the lac of oral findings does not eliminate esophageal or stomach in*ury. Treatment includes admission to the IC+ (for close monitoring to pre%ent lifethreatening complications such as mediastinitis, shoc, etc.! and immediate dilution 'y gi%ing #ater or mil. Do not attempt to -neutralie the chemical reaction/ 'y gi%ing agents such as #ea acidic or 'asic su'stances (this can lead to instantaneous damage!. (Choice A! Anticholinergic agent poisoning presents #ith dry, flushed sin and mucous mem'ranes, tachycardia, urinary retention, mydriasis and decreased gastrointestinal motility. (Choice C! TCA poisoning presents #ith cardiac arrhythmias, hypotension and anticholinergic signs (e.g., hyperthermia, flushing, dilated pupils, urinary retention, etc!. (Choice D! Cyanide poisoning causes death #ithin minutes, and is characteried 'y a 'urning sensation in the mouth, 'itter almond odor of the 'reath, initial hyperpnoea and headache follo#ed 'y hypoxic con%ulsions, respiratory arrest and death. (Choice E! Alcohol intoxication usually presents #ith altered mentation, slurred speech, euphoria or dro#siness, impaired cognition, ataxia, etc.
Educational 0'*ecti%e: )uspect caustic poisoning in a conscious patient #ith a #hite tongue, hea%y sali%ation, mouth 'urns, drooling of sali%a and dysphagia. The patient is usually in se%ere pain.
110
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USMLE WORLD STEP 2 CK 3*
(INTERNAL (INTERN AL MEDICINE) MEDICINE ) *Block
Q NO 94: A 34-ye!-ol" e5o$c "+ce! 0% &!o' o e e#e!e+cy !oo# .e! %e .ell 0$le ,e!.o!#$+ Se " &ee+ $e" +" lo'" "'!$+ e "+ce Se " %e$6'!e o+ e! 0y o e o%,$l Se e!% 1o$ce% o. c% c!y$+ .o! e! el, e! e#,e!'!e e#,e!'!e $% 378 C (899 :)/ &loo" ,!e%%'!e $% 8;9<=9 ## / ,'l%e $% =><#$+/ +" !e%,$!$o+% !e%,$!$o+% !e 8?<#$+ Py%$cl Py%$cl e5#$+$o+ %o0% "y%!!$/ 5$/ 1e!$cl +y%#'%/ +" co+.'%$o+@ %k$+ $% #o$%/ "'e o %0e$+ Ce% e5#$+$o+ %o0% "$..'%e #$l"-o#o"e!e !o+c$ 0$ ,!olo+e" e5,$!$o+ W$c o. e .ollo0$+ $% e #o% l$kely "$+o%$% A. B. C. D.
Bar'iturate intoxication 1hencyclidine intoxication Cocaine intoxication 2ari*uana Intoxication
Explanation: 1hencyclidine (1C1! intoxication is characteried 'y nystagmus, confusion, ataxia, and sensory impairment. This is the only drug of a'use that causes a characteristic %ertical nystagmus. In high doses, the drug produces seiures, se%ere hypertension, and e%en life3hreatening hyperthermia. 1sychotic ideations such as delusions or hallucinations may also 'e present (Choice B!. 1hencyclidine (101! is a 4methyl Daspartate (42DA! receptor channel 'locer and can cause dissociati%e phenomenon5 patients may exhi'it %ery dangerous 'eha%iors or %iolence. (Choice C! Cocaine is a C4) stimulant that causes tachycardia, hyper%igilance, hypertension, s#eating, mydriasis, and hypertension. (Choice A! Bar'iturates are C4) depressants and #ould cause hypotension, respiratory depression, diminished reflexes, ataxia, dro#siness, and slurred speech. (Choice D! 2ari*uana causes euphoria follo#ed 'y hypnosis, altered time perception, con*uncti%al in*ection, impaired immediate memory, and psychomotor retardation.
Educational 0'*ecti%e: 1hencyclidine (1C1! is an hallucinogenic drug and its intoxication is characteried 'y %iolence %ertical nystagmus, confusion, ataxia, and sensory impairment.
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USMLE WORLD STEP 2 CK 3*
(INTERNAL (INTERN AL MEDICINE) MEDICINE ) *Block
$%,+$c #le co#e% o yo' .o! !o'$+e el Q NO 95: A 34-ye!-ol" $%,+$c 1$%$ e "oe% +o 1e +y co#,l$+% &' $% 0o!!$e"/ % $% +e$&o! 0o 0% 1$+ y,e!cole%e!ole#$/ y,e!cole%e!ole#$/ !ece+ly "$e" o. e! ck e %k% yo' $. e +ee"% o &e %c!ee+e" .o! y,e!l$,$"e#$ Acco!"$+ o U+$e" Se% P!e1e+$1e Se!1$ce% T%k :o!ce (USPST:) '$"el$+e%/ 0$c o. e .ollo0$+ $% e #o% ,,!o,!$e e o %! %c!ee+$+ .o! l$,$" "$%o!"e!% $+ #le% 0$o' +y !$%k .co!% .o! CD A. B. C. D. E.
"6years $6 years 37 years 36years 67 years
Explanation: Coronary 8eart Disease is the leading cause of death in 'oth men and #omen of all races and ethnicities in +nited )tates. 8ypercholesterolemia is one of the ma*or modifia'le ris factor for C8D. )tudies ha%e sho#n that high le%els of total cholesterol and 9D9C and lo# le%els of 8D9C are important ris factors for coronary heart disease. The +.). 1re%enti%e )er%ices Tas &orce (+)1)T&! strongly recommends routine screening of men ata'o%e $6 and #omen ata'o%e 36 for lipid disorders. +)1)T& recommends screening for men ages "7 to $6 years and for #omen ages "7 to 36 years in the presence of any of the follo#ing: . Dia'etes. ". &amily history suggesti%e of familial hyperlipidemia. $. 1resence of multi pie ris factors for coronary artery disease. 3. &amily history of cardio%ascular disease 'efore the age of 67 years in a male relati%e or 'efore the age of ;7 years in a female relati%e. The +)1)T& maes no recommendation for or against routine screening for lipid disorders in men ages "7 to $6 years or #omen ages "7 to 36 years in the a'sence of no#n ris factors for coronary heart disease. 4o recommendations ha%e 'een made 'y +)1)T& a'out the appropriate inter%al of screening or the age to stop screening. 8o#e%er, it is reasona'le to screen indi%iduals e%ery fi%e years, #ith shorter inter%als for people #ho ha%e lipid le%els close to those #arranting therapy, and longer inter%als for lo#ris people #ho ha%e had lo# or consistently normal lipid le%els. Also lipids le%els are less liely to increase after age ;6 and so, repeated screening is less important in the elderly.
Educational 0'*ecti%e: The +.). 1re%enti%e )er%ices Tas &orce (+)1)T&! strongly recommends routine screening of men ata'o%e $6 and #omen ata'o%e 36 for lipid disorders.
112
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USMLE WORLD STEP 2 CK 3*
(INTERNAL (INTERN AL MEDICINE) MEDICINE ) *Block
Q NO 96: A ;7yearold AfricanAmerican male presents to the emergency room #ith a t#o#ee history of lo# 'ac pain and lo#grade fe%er. 8is past medical history is insignificant. 8e tried se%eral o%erthe counter pain medications #ith little success. 8is temperature is $>.$ C (7 &!, 'lood pressure is "7?; mm8g, pulse is @7min, and respirations are ;min. 1hysical examination re%eals percussion tenderness o%er the lum'ar %erte'rae and local para%erte'ral muscular spasm. 4eurological examination sho#s " deep tendon reflexes and 66 muscle po#er. The straightleg raising test is negati%e at @7 degrees. 9a'oratory %alues are: 8emoglo'in "." gd9 9euocyte count 7,?77cmm )egmented 4eutrophils ;$ Bands 3 Eosinophils $ Basop hils 7 9ymphocytes "$ 2onocytes ; 1latelets 377,777cmm E) ?6 mmhr hat is the next step in the management of this patient
A. B. C. D. E.
1lain radiograph Bone scan 2I of the spine )erum rheumatoid factor 1hysiotherapy
Explanation: The clinical scenario descri'ed is suggesti%e of %erte'ral osteomyelitis. Ferte'ral osteomyelitis is usually hematogenous, and the lum'ar area is most commonly affected. Bac pain accompanied 'y lo# grade fe%er and ele%ated E) is the typical presentation. 8ighgrade fe%er and chills are uncommon. 1hysical examination may demonstrate local tenderness on percussion o%er the affected %erte'rae and para%erte'ral muscular spasm. Early diagnosis is %ery important in patients #ith this condition, 'ecause epidural a'scess and spinal cord compression may de%elop if the treatment is delayed (Choice E!. 2I is currently the imaging modality of choice in patients #ith suspected %erte'ral osteomyelitis. Compared to a 'one scan (Choice B!, a 2I has the same sensiti%ity for detecting osteomyelitis and is less timeconsuming. 1lain radiograph (Choice A! #ould not usually detect 'one changes in acute osteomyelitis, 'ut may 'e employed in chronic osteomyelitis. )erum rheumatoid factor (Choice D! pro%ides no diagnostic information for the clinical scenario descri'ed. heumatoid arthritis rarely e%er presents #ith 'ac pain. They usually complain of pain and stiffness o%er the 2C1 and 1I1 *oints.
Educational 0'*ecti%e: 2I is the imaging procedure of choice in patients #ith suspected %erte'ral osteomyelitis.
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 97: A 44-ye!-ol" #le 0% $+1ol1e" $+ %e!$o'% #oo! 1e$cle cc$"e+ (MA) e " #'l$,le %e!$o'% $+'!$e% +" !e'$!e" #ec+$cl 1e+$l$o+ O1e! e +e5 0o "y%/ e co+$+'e% o !e'$!e #o!e o5ye+ o #$+$+ $% %'!$o+% &o1e =9 $% ce% 5-!y/ 0$c 0% cle! o+ "#$%%$o+/ +o0 %o0% &$le!l .l'..y $+.$l!e% A c!"$oloy co+%'l !'le% o' co+e%$1e e! .$l'!e +" $% %,''# c'l'!e% !e +e$1e A ,'l#o+!y co+%'l %'e%% e ,$e+ #y 1e ARDS Te ,$e+ co+$+'e% o &e "$..$c'l o o5ye+e To $#,!o1e e ,$e+% o5ye+$o+/ e &e% #eo" $% o A. B. C. D. E.
Increase the respiratory rate Increase the tidal %olume Increase 1EE1 Increase the fluids Administer 'lood
Explanation: In AD), the goal of mechanical %entilation is to impro%e oxygenation and this is 'est done 'y increasing the 1EE1. 1EE1 can increase oxygenation 'ut hemodynamics ha%e to 'e carefully measured. The a%erage increase in 1EE1 is 67 mm8g. 1EE1 opens the al%eoli at end expiration and eeps them open for a longer duration to promote oxygenation. 1EE1 has 'een a ma*or factor in impro%ing oxygenation in AD). (Choice A! Increasing the respiratory rate does not help increase oxygenation in AD). Increasing the %entilatory rate #ill decrease the C7" le%els and produce respiratory alalosis. (Choice B! Increasing the tidal %olume 'eyond the recommended >7 mlg does not help #ith oxygenation and may in fact decrease respiratory compliance. (Choice D! In AD), it is 'est to eep the patient on the dry side and a%oid fluid o%erload. Therefore, most AD) patients recei%e diuretics to help decrease the fluid o%erload. All patients #ith AD) ha%e daily chest xrays and are #eighed daily to monitor the fluid 'alance. (Choice E!Today there are strict guidelines in gi%ing 'lood. Blood transfusions are limited to patients #ho are anemic and 'leeding. Gi%ing 'lood to AD) patients is not routinely done unless the patient has a lo# hematocrit.
Educational o'*ecti%e: In AD), the one treatment that can impro%e oxygenation is the addition of 1EE1.
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 98: A $"yearold man from Aransas presents to the physician #ith a t#oday history of fe%er. headache, malaise, and myalgias. 8is family says that he seems slightly confused. 8e recalls ha%ing a tic 'ite t#o #ees ago after #aling through the #oods. 8is temperature is $@ C (7" &!, pulse is @7min, and 'lood pressure is "6>7mm 8g. 4ec is supple and there is no lymphadenopathy noted. 0ropharynx is clear. Chest auscultation is unremara'le. A'domen is soft and nontender. There is no rash e%ident. 4eurologic examination is nonfocal. 9a'oratory testing sho#s: Complete 'lood count 8emoglo'in 3.7 g9 2CF >> f9 1latelets ?>,777mmH 9euocyte count ",677mmH 4eutrophils 6; Eosinophils 9ymphocytes $$ 2onocytes 7 9i%er studies Total protein, serum ;.6 gd9 Total 'iliru'in .7 mgd9 Direct 'iliru'in 7.> mgd9 Alaline phosphatase 7 +9 Aspartate aminotransferase ()G0T! @> +9 Alanine aminotransferase ()G1T! 76 +9 hat is the most appropriate next step in the management of this patient
A. B. C. D. E. &. G. 8.
Doxycycline Chloramphenicol Erythromycin Ceftriaxone 8epatitis serology 1eripheral 'lood smear Bone marro# 'iopsy 9yme serology
Explanation: This %ignette depicts a classic case of ehrlichiosis. Ehrlichiosis is a category of tic'orne illness that is caused 'y one of three different species of Gramnegati%e 'acteria, each #ith a different tic %ector. It is endemic in the southeastern, southcentral, midAtlantic and upper 2id#est regions of the +), as #ell as California. It usually occurs in the spring or summer. The incu'ation period %aries from one to three #ees. Clinical features include fe%er, malaise, myalgias, headache, nausea, and %omiting. There is usually no rash5 hence, its description as the -spotless ocy 2ountain spotted fe%er./ 9a's often sho# leuopenia andor throm'ocytopenia, along #ith ele%ated aminotransferases. hene%er ehrlichiosis is suspected, treatment should 'e started #ithout delay, and the drug of choice is doxycycline. (Choice B! 9yme disease and 2)& may easily 'e confused #ith ehrlichiosis. Doxycycline is also the treatment of choice for 9yme disease and 2)&5 ho#e%er, chloramphenicol is used to treat 2)& in pregnant #omen. (Choice C! Erythromycin is the drug of choice for 9egionnaire=s disease.
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
(Choice E and G! 8epatitis serology is not indicated, as his ele%ated aminotransferases can 'e attri'uted to ehrlichiosis. )imilarly, 'one marro# 'iopsy is not needed 'ecause his leuopenia and throm'ocytopenia are due to ehrlichiosis, not 'one marro# dysfunction. (Choice &! 1eripheral 'lood smear may sho# intracellular inclusions (morulae! in #hite 'lood cells in patients #ith ehrlichiosis, #hich can 'e helpful in esta'lishing the diagnosis. 8o#e%er, diagnostic confirmation is not necessary prior to initiating treatment. (Choice 8! This patient most liely has ehrlichiosis, so treatment should 'e instituted rather than o'taining serology to test for other conditions. Educational 0'*ecti%e: )uspect ehrlichiosis in any patient from an endemic region #ith a history of tic 'ite, systemic symptoms, leuopenia andor throm'ocytopenia, and ele%ated aminotransferases. The drug of choice is doxycycline.
116
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 99: A 49-ye!-ol" 0o#+ ,!e%e+% 0$ "$..$c'ly cl$#&$+ %$!% +" k+eel$+ "o0+ .o! e ,% co',le o. #o+% Se l%o !e,o!%/ "$..$c'ly $+ %0llo0$+ .oo" .o! e ,% .e0 0eek% Se "e+$e% +y #'%cle ,$+/ .c$l/ o! oc'l! #'%cle 0ek+e%% +" %k$+ !% o! ,$#e+$o+ E5#$+$o+ !e1el% #$l" !o,y +" 0ek+e%% o. ,!o5$#l #'%cle% $+ &o e5!e#$$e% Se+%$o+ +" "ee, e+"o+ !e.le5e% !e $+c W$c o. e .ollo0$+ el,% $+ e %,ec$.$c "$+o%$% o. $% ,!e%e+$o+ A. B. C. D. E.
)erum aldolase le%els 2 of 'oth thighs Electromyography 1ositi%e anti nuclear anti'ody 2uscle 'iopsy
Explanation: Explanation: 1olymyositis is an inflammatory muscle disease of unno#n etiology. It presents as proximal #eaness characteried 'y difficulty ascending and descending stairs, com'ing hair, neeling do#n etc. There are no sin rash or scaly patches as seen in dermatomyositis. Though some patients present #ith muscle pain and tenderness, it is not %ery typical in ma*ority. These patients ha%e dysphagia due to in%ol%ement of the striated muscles of the upper pharynx. 2uscle 'iopsy is the 'est diagnostic study for polymyositis. It sho#s endomysial infiltration of the inflammatory infiltrate. Choice (A!: )erum aldolase le%els are ele%ated in polymyositis. These are useful in assessing the disease acti%ity, 'ut not %ery specific for diagnosis. Choice (B!: 2I of 'oth thighs sho#s signal intensity changes in muscle due to inflammation and scarring, useful in guiding muscle 'iopsies. Choice (C!: Electromyography re%eals the myopathic a'normalities. Again, doesn=t tell you the exact diagnosis. Choice (D!: 1ositi%e anti nuclear anti'ody is found in ma*ority of patients #ith polymyositis and in other autoimmune conditions 'ut not diagnostic for this condition.
Educational 0'*ecti%e: 2uscle 'iopsy is the 'est diagnostic study for polymyositis.
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 100: A >4-ye!-ol" #le/ 0o !!ely %ee% e "oco! +" "oe%+ &el$e1e $+ %c!ee+$+ ,!oce"'!e%/ co#e% o o..$ce 0$ e co#,l$+ o. %e1e!e &ck ,$+ e % +o .el co#.o!&le .o! e ,%4 #o+% +" $% 1$+ %e1e!e ,$+ $+ e &ck e % .o'+" $ "$..$c'l o %lee, e % y,e!e+%$o+/ .o! 0$c e ke% y"!oclo!o$6$"e% !e'l!ly e $+k% e % lo% %o#e 0e$ O+ e5#$+$o+/ $% BP $% 8>;<=9## o. 0$le !e% o. 1$l% !e %&le O+ !ecl e5#$+$o+ yo' .$+" !ock !" 2 c# +o"'le $+ ,!o%e B$o,%y %o0% ,oo!ly "$..e!e+$e" "e+oc!c$+o# Bo+e %c+% %o0% 0$"e %,!e" #e%%$% ll o1e! $% %keleo+ W $% e #o% ,,!o,!$e !e#e+ .o! $% #e%$c "$%e%e A. B. C. D. E.
9euprolide Diethylstil'estrol (DE)! &lutamide adicle prostatectomy Complete androgen 'locade #ith 9euprolide and &lutamide
Explanation: The patient has prostate cancer that has metastasied to 'ones. 1rostate cancer is one of the leading causes of cancer deaths among men in +)A. At the time #hen the cancer is in late stages, surgery is not performed unless needed for palliation. 1alliati%e radiation, along #ith antiandrogen therapy, is the treatment of choice. Antiandrogen therapy consists of 9euprolide (988 analogue!. &lutamide is considered inferior to 988 analogues, though some studies ha%e sho#n added 'enefit of com'ining the t#o. In %arious studies the results #ith antiandrogen therapy are compara'le to orchiectomy: ho#e%er, longterm sur%i%al in orchiectomy is not yet completely studied. Complete androgen 'locade (CAB! using com'ination of 988 analogue #ith an antiandrogen has 'een tested in %arious trials. 2ost studies reported a higher incidence of ad%erse e%ents #ith CAB, 'ecause of the addition of an antiandrogen, and e%en the 'enefit is ye# modest. )o far, there is no clear consensus on the ad%antage of CAB o%er monotherapy as firstline therapy for metastatic prostate cancer. DE) is associated #ith increased cardio%ascular disease and is not used anymore.
Educational 0'*ecti%e: 1alliati%e radiation, along #ith antiandrogen therapy, is the treatment of choice for metastatic prostate cancer. Antiandrogen therapy consists of 9euprolide (988 analogue!. &lutamide is considered inferior to 988 analogues.
118
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 101: A ;>-ye!-ol" "$&e$c #le ,!e%e+% o e ER .o! %'""e+ o+%e o. ce% ,$+/ &!ele%%+e%%/ +'%e/ 1o#$$+/ +" "$,o!e%$% 2 o'!% o $% ce% ,$+ %!e" !e% +" !"$e% o $% lo0e! 0 +" le. !# Te ,$+ $% ,!$lly !el$e1e" &y %'&l$+'l +$!olyce!$+ e $% +o+%#oke! +" +o+-lcool$c e "oe% +o 1e +y $%o!y o. %#/ COPDI o! "y%l$,$"e#$ $% .e! "$e" o. + Ml 0e+ e 0% ;9 $% "$&ee% 0% "$+o%e" 2 ye!% o +" e $% o+ ly&'!$"e .o! lyce#$c co+!ol e l%o %'..e!% .!o# e%%e+$l y,e!e+%$o+ .o! 0$c e ke% e+l,!$l O+ e5#$+$o+/ PR 7><#$+@ BP $% 83=<7= ##@ RR 83<#$+@ Te#,e!'!e 373 C (== :) Ce% 5-!y $% +o!#l EKF %o0% %y##e!$cl T 01e $+1e!%$o+ $+ le"% 8-4 Te $+$$l %e o. c!"$c e+6y#e% !e +e$1e W$c o. e .ollo0$+ e!,$e% $% e #o% ,,!o,!$e $+ e #+e#e+ o. $% ,$e+ A. B. C. D.
IF heparin, 'eta'locers and aspirin IF tissue plasminogen acti%ator, aspirin, 'eta'locers IF heparin, IF tissue plasminogen acti%ator, and 'eta'locers Aspirin, IF amiodarone, IF magnesium, 'eta'locers
Explanation: Explanation: This patient has unsta'le angina as he has typical ischemic chest pain only partially relie%ed 'y nitroglycerin T #a%e in%ersion in the anteroseptal leads and negati%e cardiac enymes. Treatment #ith IF heparin, aspirin, 'eta'locer, and nitroglycerin is indicated in cases of unsta'le angina and non #a%e infarcts. In these cases, throm'olytic therapy has not 'een sho#n to 'e associated #ith a mortality 'enefit. Throm'olytic therapy is indicated #hen the chest pain is suggesti%e of 2I and there is documented )T segment ele%ation greater than mm in t#o contiguous leads after su'lingual nitroglycerin administration to rule out coronary %asospasm. Another indication for throm'olytic therapy is ne# or presuma'ly ne# left 'undle 'ranch 'loc. Throm'olytic therapy is not indicated for an acute 2l #ith )T segment depression and it is also not indicated for unsta'le angina as in these settings no 'enefit has 'een demonstrated. Throm'olytic therapy can 'e gi%en #hen )T depression occurs in a posterior 2I especially in the setting of an inferior #all 2I (in that situation it is the eJui%alent of )T segment ele%ation, only seen 'ac#ards, in a mirror!. Throm'olytic therapy, #ith tissue plasminogen acti%ator, reJuires co administration of heparin and aspirin for additional 'enefit. Tissue plasminogen acti%ator is slightly more effecti%e than streptoinase 'ut it carries a slightly more ris of intracranial 'leeding. &or streptoinase, coadministration of heparin is not reJuired 'ecause it may produce allergy. IF amiodarone and IF magnesium are not useful in the setting of unsta'le angina unless there is a specific indication.
Educational 0'*ecti%e: Throm'olytic therapy is not indicated for unsta'le angina or non)T ele%ation (non K= #a%e! 2l. The treatment of unsta'le angina primarily includes aspirin, 'eta'locers, heparin and nitroglycerin.
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 102: A 7>-ye!-ol" #+ 0% o,e!e" o+ .o! %!+'le" $+'$+l e!+$ 49 c# o. %#ll &o0el 0% !e%ece" O+ e #o!+$+ o. e $!" ,o%-o,e!$1e "y e .ll% 0$le e$+ o' o. &e" 0$ e $" o. ,y%$!$% I##e"$ely .e! e .ll e $% !e%,o+%$1e lo' $% %,eec $% %l'!!e" +" e c+ e5,l$+ 0 % ,,e+e" $% 1$l% !e/ PR 829<#$+/ BP 49<9## PR 29<#$+ L'+% +" e! !e cle! o '%c'l$o+ 0$ +o ,olo$c .$+"$+% Neck 1e$+% !e "$%e+"e" ECF $% !e#!k&le .o! +e0 o+%e !$ &'+"le &!+c &lock (RBBB) I##e"$e !e%'%c$$o+ $% %!e"/ &' e &eco#e% '+!e%,o+%$1e A l$le le! $% ,',$l% %! o "$le +" $% e! !e .ll% o ;; W $% e #o% l$kely "$+o%$% A. B. C. D. E.
8ypo%olemia accompanied #ith syncope )troe 2yocardial infarction 1ostoperati%e hemorrhage 2assi%e pulmonary throm'oem'olism
Explanation: Lugular %enous distention (LFD! and BBB indicate right heart strain. These findings could 'e due to a right %entricular myocardial infarction (2l!, 'ut pulmonary em'olism (1E! is more liely. This is 'ecause of the accompanying circumstances of a serious operation in an older patient, #ho has 'een 'ed 'ound postoperati%ely and occurrence #hile sitting up from the 'ed. In fact, this is one of the classic presentations for a massi%e 1E. The neurologic changes (Choice B! are secondary to the hypotension and 'rain ischemia. The 'radycardia is another ominous sign indicating that the patient has a %ery poor prognosis. 8ypo%olemia due to either penoperati%e dehydration (Choice A! or postoperati%e hemorrhage (Choice D! #ould result in LF collapse rather than LFD.
Educational 0'*ecti%e: Thin of 1E in a postoperati%e patient #ith LFD and ne# onset BBB.
120
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 103: A %'"y co+ce!+$+ e !el$o+%$, o. e co##o+ col" 0$ e +'#&e! o. c$!ee% %#oke" ,e! "y 0% c!!$e" o' Te !e%e!c 0% co+"'ce" &y 4 ye! #e"$cl %'"e+% +" %,o+%o!e" &y e P'&l$c el De,!#e+ o. e collee Me"$cl %'"e+% 0$ co##o+ col" %y#,o#% 0e!e %ke" o .$ll o' 'e%$o++$!e &o' e$! %'%/ +'#&e! o. ,ck% %#oke" ,e! "y/ +" "'!$o+ o. %#ok$+ W$c o. e .ollo0$+ .co!% 0$ll #o% l$kely $+1l$"e e .$+"$+% o. $% %'"y A. B. C. D. E.
Admission rate 'ias Inter%ie#er=s 'ias ecall 'ias +naccepta'ility 'ias 9ead time 'ias
Explanation: +naccepta'ility 'ias may affect the findings of the a'o%e study, particularly 'ecause the study #as conducted on medical students. )ur%eys and polls are crosssectional studies. +naccepta'ility 'ias occurs #hen participants in such studies purposely gi%e desira'le responses, #hich lead to the underestimation of ris factors. In this example, medical students no# the ris of smoing, and may purposely not re%eal their smoing status, especially to the 1u'lic 8ealth Department. A lo#er than the actual num'er of cigarettes smoed may'e reported there'y significantly affecting the results of the study. (Choice A! Admission rate 'ias refers to a distortion in ris ratio due to different hospitals= admission of certain cases. &or instance, patients #ith cardiac diseases may prefer to 'e admitted to a particular hospital. (Choice C! ecall 'ias is caused 'y the difference in the a'ilities of persons to recall facts regarding ris factor exposure. (Choice E! 9ead time 'ias is caused 'y the chronology 'et#een the diagnosis and treatment of different cases. )uch differences in chronology 'et#een treatment and diagnosis could affect the outcome of the study.
Educational 0'*ecti%e: +naccepta'ility 'ias occurs #hen participants purposely gi%e desira'le responses #hich lead to the underestimation of ris factors.
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 104: A 3?yearold #oman comes to the office and complains of 'urning a'dominal pain #hich has 'een present for the past $ months, is grade ;7 in se%erity, continuous, and relie%ed 'y taing antacids. )he also complains of some constipation. 8er father has a history of -ulcers in his 'elly./ )he #ors as a floor secretary in a surgical #ard, and is not happy #ith her ne# 'oss. )he denies any #eight loss or decreased appetite. 8er temperature is $?. C (@>.> &!, 'lood pressure is $7>6mm 8g, heart rate is ?>min, and respirations are 3min. )he is a#ae, alert, and oriented. The a'dominal examination re%eals normoacti%e 'o#el sounds and tenderness in the epigastric region, 'ut no palpa'le mass. 8er stools are occult 'lood positi%e. ECG re%eals increased 1 and shortened CT inter%als. The la'oratory results re%eal the follo#ing: )odium $? mEJd9 1otassium 3." mEJd9 Chloride 7 mEJd9 Bicar'onate "? mEJd9 Calcium ".7 mgd9 1hosphorus "." mgdl B+4 $? mgd9 Creatinine .> mgd9 hich of the follo#ing is the most liely diagnosis
A. B. C. D. E.
Glucagonoma )tress ulcer 1arathyroid adenoma FitaminD toxicity 2etastatic gastric carcinoma
Explanation: This patient most liely has multiple endocrine neoplasia (2E4! Type . This condition can 'e composed of MollingerEllison )yndrome (ME)! and a parathyroid adenoma. ME) is caused 'y a gastrinproducing tumor called gastrinoma, causing se%ere and refractory peptic ulcer disease (1+D!. 1arathyroid adenoma is characteried 'y increased calcium and decreased phosphorus le%els. Interestingly, hypercalcemia leads to the increased release of gastrin, #hich may encourage peptic ulcer formation. In this case, the patient=s presentation of hypercalcemia and peptic ulcers is classic for 2E4. (Choice A! Glucagonoma is characteried 'y hyperglycemia, dermatitis, #eight loss, and anemia. (Choice B! )tress ulcers are usually seen in se%erely ill patients #ho are 'eing managed in IC+ settings. (Choice D! FitaminD toxicity may lead to hypercalcemia, 'ut the history is not suggesti%e of this diagnosis. &urthermore %itaminD toxicity may cause ele%ated phosphate (rather than decreased! le%els. (Choice E! E%e gastric ulcer has to 'e in%estigated for malignancy. Although #e ha%e a plausi'le reason for this patient=s gastric ulcer (i.e., hypercalcemia!, this is no excuse for not doing a 'iopsy of the lesion. A reasona'le argument is that ad%anced gastric cancer is unliely #ithout any constitutional symptoms. &urthermore, measurement of increased 1T8 le%els may confirm the diagnosis and resol%e this issue.
Educational 0'*ecti%e: 8ypercalcemia and intracta'le ulceration can 'e due to 2E4 syndromes. 122
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 105: 2s. 9ee, a ;"yearold Chinese #oman, comes #ith yello#ness in her eyes for the past ; #ees. )he is generally feeling tired, has lost some #eight, and occasionally had some nausea. )he denies any altered 'o#el ha'its. )he is a nonsmoer 'ut drins "$ 'eers each night. 8er dad is suffering from high cholesterol and also has had stroe. )he had a dilatation and curettage for an a'normal pap smear 6 years ago. 8er %itals are sta'le and she is afe'rile. )he has mared scleral icterus. An a'dominal examination re%eals normal 'o#el sounds and no organomegaly. 8er stools #ere occult 'lood negati%e. 8er li%er function tests and enymes #ere ordered and the results are Total protein ;. gd9 Al'umin $.@ gd9 A)T ; +9 A9T 6" +9 Alaline phosphatase "@7 +9 Total 'iliru'in @.; mgd9 Direct 'iliru'in >.@ mgd9 )erum lipase is 3; +9 Antimitochondrial anti'odies negati%e hich of the follo#ing is the most liely cause of these findings
A. B. C. D. E.
1rimary 'iliary cirrhosis Chronic pancreatitis Firal hepatitis 1ancreatic carcinoma 8epatocellular carcinoma
Explanation: Explanation: 1ainless o'structi%e *aundice is more liely to 'e due to malignancy. Adenocarcinoma of the head of pancreas causes o'struction of extra hepatic 'ile duct leading to ele%ation of direct 'iliru'in and mared icterus. It may 'e associated #ith #eight loss, dull 'ac pain, and anorexia. There is astronomical ele%ation of alaline phosphatase. A'dominal examination is usually negati%e except for mild tenderness in epigastric region. CT scan may help in diagnosis. The cancer has got %ery 'ad prognosis (Choice D!. (Choice A! 1rimary 'iliary cirrhosis also has increased alaline phosphatase 'ut it usually presents #ith itching and also has characteristic antimitochondrial anti'odies detected on anti'ody assay. (Choice B! Chronic pancreatitis alone does not cause ele%ation of alaline phosphatase. The patient also doesn=t ha%e any chronic a'dominal pain or e%idence of mala'sorption. (Choices C and E! Both A9T and A)T should 'e high incase of Firal hepatitis and hepatocellular carcinoma.
Educational 0'*ecti%e: 1ainless *aundice in an elderly patient should mae you thin a'out pancreatic head carcinoma.
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 106: A ;8-ye!-ol" .e#le co#e% o e o..$ce .o! !o'$+e 1$%$ Se $% ,,!e+ly ely +" "oe% +o 1e +y co#,l$+% Py%$cl e5#$+$o+ !e1el% y!o$" +o"'le Se $% %'!,!$%e" o e! &o' e +o"'le +" %k% Go0 o.e+ "oe% $% ,,e+ W co'l" 1e c'%e" $%H W$c o. e .ollo0$+ $% e #o% co##o+ c'%e o. y!o$" +o"'le% A. B. C. D. E. &.
&ollicular adenoma Colloid nodule 1apillary carcinoma &ollicular carcinoma Anaplastic carcinoma 2edullary carcinoma
Explanation: 2ost thyroid nodules are 'enign colloid nodules. (Choice A! The second most common cause of thyroid nodules is follicular adenoma. (Choices C, D, E and &! &actors #hich increase the ris of thyroid malignancy are a positi%e family history of thyroid cancer and a positi%e history of nec irradiation in childhood. The chances of thyroid cancer in a patient #ith a thyroid nodule are less than 0. 2alignant causes of thyroid nodules, in the order of decreasing freJuency. are: papillary, follicular, anaplastic and medullary carcinoma. &ine needle aspiration 'iopsy (&4AB! can 'e used to detect the characteristic nuclear changes of papillary cancer5 ho#e%er, &4AB cannot 'e used to differentiate follicular adenoma from follicular cancer. 2edullary thyroid cancer is one of the components of multiple endocrine neoplasia (2E4! " A and " B5 therefore, its occurrence should al#ays raise your suspicion for 2E4.
Educational 0'*ecti%e: 2ost thyroid nodules are 'enign colloid nodules.
124
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 107: A 27-ye!-ol" #le ,!e%e+% o yo' 0$ co#,l$+% o. co'/ ce% "$%co#.o! +" "y%,+e o+ e5e!$o+ e %y% e % lo% 89 l&% $+ 0e$ o1e! e ,% 2 #o+% e % &ee+ %#ok$+ 8 ,ck ,e! "y .o! e ,% 89 ye!% e "!$+k% 2 &ee!% $+ e 0eeke+" e "e+$e% $llel "!' '%e +" #'l$,le %e5'l ,!+e!% E5#$+$o+ $% '+!e#!k&le Ce%-5 !y !e1ele" l!e +e!$o! #e"$%$+l #%% Bloo" 0o!k !e1el% e % ele1e" le1el% o. CF +" l. .eo,!oe$+ (A:P) W $% e #o% l$kely "$+o%$% A. B. C. D. E. &. G. 8. I. L. <. 9. 2. 4. 0. 1. . .
Benign teratoma )eminoma 4onseminomatous germ cell tumors 1ericardial cysts Thymoma 8odgin=s lymphoma 4on8odgin=s lymphoma Tu'erculoma 1arathyroid adenoma Carcinoid )Juamous cell carcinoma of the lung )mall cell cancer of the lung 8epatocellular carcinoma Benign sch#annoma Bronchogenic cyst )arcoidosis 8istoplasmosis Choriocarcinoma
Explanation: The a'o%e patient has a large anterior mediastinal mass #ith ele%ated le%els of 8CG and A&1. These findings alone are diagnostic of a germ cell tumor of the mediastinum. 1rimary mediastinal germ cell tumors occur in young males and are locally in%asi%e. A&1 and 8CG ele%ations are indicati%e of a nonseminoma and therapy can 'e started e%en #ithout a tissue 'iopsy. 4onseminomas can 'e treated #ith cis platinum 'ased multi agent chemotherapy. These tumors are %ery aggressi%e and in the ma*ority of patients gro# to %ery large sie 'efore a diagnosis is made. Chemotherapy is administered for ; #ees and A&1 and 8CG are used to monitor response to therapy (0ption C!.
Educational o'*ecti%e: Anterior mediastinal mass along #ith ele%ated A&1 and 8CG indicates 4onseminomatous tumor.
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 108: A 24-ye!-ol"0o#+ co#e% o e ,y%$c$+ &ec'%e o. 24o'!$%o!o. !$ .l+k ,$+/ &'!+$+ #$c'!$$o+ +" $-!"e .e1e! 0$ c$ll% e! e#,e!'!e $% 892 : (3?= C)/ &loo" ,!e%%'!e $% =9<>9## / ,'l%e $% 839<#$+/ +" !e%,$!$o+% !e 29<#$+ Py%$cl e5#$+$o+ %o0% co%o1e!e&!l +le e+"e!+e%% W$c o. e .ollo0$+ $% e #o% l$kely '!$+e "$,%$ck .$+"$+ $+ $% ,$e+ A. B. C. D.
1ositi%e 1ositi%e 1ositi%e 4egati%e
for for for for
nitrites and esterase nitrites only esterase only 'oth esterase and nitrites
Explanation: Dipstics are commercially a%aila'le its that detect the presence of leuocyte esterase and nitrites in the urine of patients #ith suspected +TI. 9euocyte esterase in the urine indicates significant pyuria, #hereas nitrites signify the presence of Entero'acteriaceae, #hich con%erts urinary nitrates to nitrites. (emem'er, though, that the most liely responsi'le organism of +TI is E. coli.! The ad%ent of dipstic testing has significantly reduced the cost associated #ith urine culture5 ho#e%er, dipstics are associated #ith a high false positi%e rate and high false negati%e rate. &or this reason, a negati%e dipstic test in a patient #ith symptoms of +TI should still ha%e urine cultures done. In this case, the patient=s clinical presentation (i.e., pyuria, significant 'acteriuria! is highly suggesti%e of acute pyelonephritis. The expected dipstic finding is positi%e for 'oth nitrites and esterase.
Educational 0'*ecti%e: Dipstics are commercially a%aila'le its that detect the presence of leuocyte esterase and nitrite in the urine of patients #ith suspected +TI. 1ositi%e leuocyte esterase signifies significant pyuria and positi%e nitrites indicate the presence of Entero'acteriaceae.
126
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 109: A 27-ye!-ol"/ I-,o%$$1e #+ co#e% o $% ,y%$c$+ 0$ 0o-"y $%o!y o. .e1e!/ ,!o.'%e 0e!y "$!!e/ +" &"o#$+l c!#,% e % &ee+ k$+ 6$"o1'"$+e/ "$"+o%$+e/ +" $+"$+1$! .o! e ,% e$ #o+% $% e#,e!'!e $% 37=9 (8992 :)/ ,'l%e $% 892<#$+/ !e%,$!$o+% !e 84<#$+/ +" &loo" ,!e%%'!e $% 89;<79 ## e $% %!e" o+ .l'$" +" elec!olye %',,o! W $% e #o% ,,!o,!$e +e5 %e, $+ e #+e#e+ o. $% ,$e+ A. )top anti retro%iral therapy and send stool for Clostridium difficile toxin assay B. Colonoscopy #ith 'iopsy of the colonic mucosa C. )tool examination for o%a and parasites D. )tart empiric anti'iotics for cytomegalo%irus E. 9operamide and lactosefree diet until diarrhea su'sides Explanation: Diarrhea in 8I Finfected patients can 'e due to multiple etiological agents, including )almonella, )higella, Campylo'acter, Clostridium difficile, Giardia, Cryptosporidium, 2yco'acterium a%ium complex, and cytomegalo%irus. Therefore, the etiology must 'e identified 'efore starting anti'iotic therapy. E%aluation of diarrhea in 8IFinfected patients should include stool culture, examination for o%a and parasites, and test for C. difficile toxin. (Choice A! It is more liely that an infecti%e organism is causing the diarrhea, rather than an anti%iral medication especially gi%en the length of time he has 'een taing the medications. +nlie many anti'acterial agents, anti%iral drugs are not associated #ith Clostridium difficile infection. (Choice B! Colonoscopy and 'iopsy of the mucosa andor any ulcers are reser%ed for those #ith persistent diarrhea and negati%e stool examination. (Choice D! Anti'iotic therapy should 'e instituted once a diagnosis is esta'lished. (Choice E! It is un#ise to use an antidiarrheal agent in a patient #hose diarrhea is liely infectious. 2ore organisms or toxin #ould remain in the intestine if such an agent #ere used, #hich could lead to toxic megacolon.
Educational 0'*ecti%e: In 8IFinfected patients, diarrhea can 'e due to a %ariety of organisms. Therefore, an attempt should 'e made to identify the causal organism prior to instituting therapy so that an appropriate anti'iotic may'e chosen.
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 110: A ;4-ye!-ol" .e#le co#,l$+% o. #'%cle 0ek+e%% Se "e%c!$&e% "$..$c'ly e$+ ', .!o# c$! +" co#&$+ e! $! Se "oe% +o '%e o&cco/ lcool o! "!'% Se ke% +o #e"$c$o+ e! 1$l %$+% !e 0$$+ +o!#l l$#$% Py%$cl e5#$+$o+ !e1el% &$le!l ,o%$% W$c o. e .ollo0$+ $% e #o% l$kely c'%e o. $% ,$e+% co#,l$+% A. B. C. D. E. &. G. 8. I. L. <.
Ischemic stroe Epidural hematoma )u'dural hematoma Thyroid myopathy 2ultiple sclerosis 9ateral amyotrophic sclerosis 2ononeuropathy 1olyneuropathy Electrolyte distur'ance Inflammatory myopathy 4euromuscular *unction disease
Explanation: 1tosis is commonly seen #ith neuromuscular disorders, typically myasthenia gra%is and 'otulism. This patient has myasthenia gra%is (2G!, a disease of the neuromuscular *unction (42L!. The clinical presentation in%ol%es fluctuating #eaness in %oluntary muscles, there'y causing diplopia, ptosis, and extremity #eaness. Extraocular #eaness is the presenting symptom in o%er half of patients. (Choices A L! 1tosis is not an important clinical feature of any of the other mentioned choices.
Educational 0'*ecti%e: It is important to distinguish 'et#een the different patterns of muscle #eaness. The hallmar of myasthenia gra%is is decreasing muscular strength #ith continued contraction. hile this can affect any seletal muscle, extraocular symptoms (e.g., diplopia! are most common.
128
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 111: A 72-ye!-ol" "$&e$c #+ ,!e%e+% 0$ $-!"e .e1e!/ c$ll%/ &'!+$+ #$c'!$$o+ +" le!e" #e+l %'% e $% 1$+ lo0e! &"o#$+l ,$+ o+ $% le. %$"e e % $%o!y o. clc$'# o5le !e+l %o+e% +" 0o ,!e1$o'% e,$%o"e% o. lo0e! '!$+!y !c $+.ec$o+ e $% &e$+ !ee" 0$ $+%'l$+ .o! $% "$&ee% #ell$'% $% ,'l%e $% 892<#$+/ Bloo" P!e%%'!e $% =9<;> ##/ Te#,e!'!e $% 49 C (894:) +" Re%,$!o!y !e $% 24<#$+'e e $% co+.'%e" +" "$%o!$e+e" Ce% '%c'l$o+ !e1el% "$..'%e &$le!l c!e,$$o+% Ce% !"$o!,y %o0% "$..'%e &$le!l l1eol! $+.$l!e% 0$ ,!o#$+e+ $! &!o+co!#% L& %'"$e% %o0 e#oc!$ o. 3;/ WBC co'+ o. 8;/999<#$c!oL/ ,lele co'+ o. 8=9/999<#$c!oL/ &loo" l'co%e o. 889 #<"L A!e!$l &loo" % +ly%$% %o0% , o. 74=/ PC2 o. 2? ##/ +" PO2 o. 4= ## e $% $+'&e" +" %!e" o+ 899 o5ye+ &' $% co+"$$o+ "$" +o $#,!o1e e $% %'%,ece" o &e %'..e!$+ .!o# "'l !e%,$!o!y "$%!e%% %y+"!o#e (ARDS) %eco+"!y o '!o%e,%$% W$c o. e .ollo0$+ #o% l$kely %'e%% ARDS $+ $% ,$e+ A. B. C. D. E.
4ormal pulmonary capillary #edge pressure Increased compliance of the lung 4ormal protein concentration in pulmonary edema fluid 4ormal pulmonary arterial pressure 4ormal al%eolararterial 10" gradient
Explanation: AD) results from diffuse inflammatory in*ury to the al%eoli of lungs. Inflammatory mediators are released as a result of local or distant tissue in*ury. 4eutrophils recruited to the lungs 'ecome acti%ated and release proteases and free oxygen radicals #hich damage al%eolar endothelial and epithelial cells. Al%eolar capillary permea'ility increases and protein is released into al%eoli increasing osmotic pressure in al%eoli and as a result, free #ater is also dragged into the al%eoli. Accumulation of protein rich fluid in al%eoli as a result of diffuse al%eolar damage maes the lungs stiff and they 'ecome less distensi'le or compliant. Al%eolararterial 10" difference is #idened in cases of AD) and hypoxemia occurs as a result. It occurs largely due to %entilationperfusion mismatch. 1ulmonary hypertension is %ery common in AD) and it occurs as a result of hypoxemic %asoconstriction of pulmonary %asculature. 1ulmonary capillary #edge pressure is normal in AD) and it is the most important differentiating point 'et#een AD) and cardiogenic pulmonary edema. It is usually less than 6 mm8g in AD) #hile itis greater than > mm8g in cardiogenic pulmonary edema.
Educational 0'*ecti%e: mm8g fa%ors AD) o%er cardiogenic pulmonary edema. ". 1a0" to &i0" ratio of "77 mm8g or less, regardless of the le%el of 1EE1. $. Diffuse, 'ilateral infiltrates on chestN ray.
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 112: A ;3-ye!-ol" $%,+$c .e#le co#e% o yo'! o..$ce co#,l$+$+ o+e 0eek o. %o!e !o +" 0o!%e+$+ co' 0$ $ck/ &!o0+ %,''# :o! e l% 2 "y%/ %e l%o +o$ce" 0$e +" !ee+ co$+ o+ e! o+'e +" co#,l$+e" o. .eel$+ l$ke .oo" $% %$ck$+ $+ e! e%o,'% Se "e+$e% +y .e1e!/ c$ll% o$+ ,$+%/ 1o#$$+ o! ce% ,$+ Se % y,e 2 "$&ee% #ell$'%/ &' $% +o co#,l$+ 0$ e! #e"$c$o+% I+ e! c! yo' +oe %e " ,!e1$o'%ly "oc'#e+e" c!o+$c &!o+c$$% Se l%o % $%o!y o. y,e!cole%e!ole#$/ y,e!e+%$o+ +" o+yco#yco%$% Se " '+"e!o+e co!o+!y !e!y &y,%% .o! !ee-1e%%el "$%e%e/ %$5 ye!% o Se !e,o!% %e $% %$ll %#ok$+ o+e ,ck o. c$!ee% ,e! "y/ &' "e+$e% +y lcool co+%'#,$o+ Se $% k$+ e+olol/ y"!oclo!o$6$"e/ ly&'!$"e/ %$#1%$+ +" %,$!$+ O+ e5#$+$o+/ e!e $% 0$e co$+ o+ e o+'e +" 0$e ,l'e% !e %ee+ %ce!e" o1e! e &'ccl #'co% Te !e% o. e ,y%$cl e5#$+$o+ $% '+!e#!k&le/ $+cl'"$+ +o!#l l'+ '%c'l$o+ W$c o. e .ollo0$+ $% e #o% ,,!o,!$e +e5 %e, $+ #+e#e+ A. B. C. D. E.
Do rapid streptococcal antigen test 1rescri'e penicillin <08 preparation Throat culture 1rescri'e aithromycin
Explanation: This patient is suffering from a candidal infection of the mouth and esophagus. 8er poorly controlled dia'etes is an important ris factor in the de%elopment of oral thrush and esophageal candidiasis. E%en though her cough is producti%e #ith 'ro#n colored sputum, the clinical suspicion of pneumonia #ithout fe%er and ill appearance is lo#. 8er sputum and cough are liely due to her chronic 'ronchitis. A simple <08 preparation in the office #ill esta'lish the diagnosis gi%en this classic presentation. Administering any ind of anti'iotics to this patient #ill #orsen her condition. apid strep test and culture are not reJuired initially, 'ut they can 'e ordered if the <08 is negati%e.
Educational 0'*ecti%e: Al#ays consider Candida al'icans as a possi'le cause of infection in a patient #ith uncontrolled dia'etes mellitus.
130
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 113: A $;yearold male is 'rought to the emergency department due to confusion, nausea and decreased arousal. 8e is una'le to ans#er Juestions and no other history is a%aila'le. 8is temperature is $;.? C (@>." &!, respirations are ""min and pulse is >;min. 8is ABG and serum electrolyte le%els are sho#n 'elo#: 18 ?." 8C0$ " mEJ9 1a0" @; mm 8g 1aC0" $7 mm 8g )erum sodium 37 mEJ9 )erum potassium $.; mEJ9 Chloride @7 mEJ9 Bicar'onate > mEJ9 Blood urea nitrogen $7 mgd9 )erum creatinine 7.> mgd9 hat is the most liely primary acid'ase disorder in this patient
A. B. C. D. E.
4onanion gap meta'olic acidosis Anion gap meta'olic acidosis 2eta'olic alalosis espiratory alalosis espiratory acidosis
Explanation: The patient descri'ed has an anion gap meta'olic acidosis. This is e%idenced 'y his acidic p8 (O ?.$6! and his se%ere primary decrease in 8C0$ (OO "3 mEJ9!. 4ormally, the anion gap is made up of negati%ely charged molecules such as protein, citrate, phosphate and sulfate that are normally present in serum. These molecules account for the normal anion gap %alue of ; " mEJ9. The AG can 'e calculated using the follo#ing formula: AG P 2easured cations (positi%e charge! 2easured anions (negati%e charge! Because the ma*or cation in the serum is 4a, and the ma*or anions in the serum are Cl and 8C0$, the formula for plasma AG can 'e simplified as follo#s: AG P 4a (8C0$ Cl! +sing this formula #ith the patient=s la'oratory %alues, the calculated anion gap is 3" mEJ9, an a'normally ele%ated %alue. An increase in the AG indicates the presence of nonchloridecontaining acids that contain inorganic (phosphate, sulfate!, organic (etoacids, lactate, uremic organic anions!, exogenous (salicylate or ingested toxins #ith organic acid production! or unidentified anions. The most common causes of anionic gap meta'olic acidosis and their corresponding unmeasured anions that compose the anion gap are: . 9actic acidosis (lactate! ".
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Q NO 114: A 33-ye!-ol" #+ ,!e%e+% 0$ lo0-!"e .e1e!/ &"o#$+l c!#,%/ +" "$!!e .o! e ,% %$5 o'!% e % " e$ e,$%o"e% o. loo%e/ 0e!y %ool co+$+$+ &loo" +" #'c'% o1e! $% $#e ,e!$o" L% +$/ e e %!$#, +" c!& #e locl !e%'!+ $% c'!!e+ ,'l%e $% ?;<#$+/ &loo" ,!e%%'!e $% 889
)higella species Enterohemorrhagic E. coli Fi'rio parahaemolyticus Rersinia enterocolitica Campylo'acter *e*uni )taphylococcus aureus Clostridium perfringens Fi'rio cholera
Explanation: Diarrhea due to Fi'rio parahaemolyticus is usually transmitted 'y the ingestion of seafood. 0ther signs and symptoms include fe%er, a'dominal cramps, and nausea. These clinical features de%elop after an incu'ation period of four hours to four days. F. parahaemolyticus can cause either #atery or 'loody diarrhea. (Choice A! )higella is a %ery common cause of dysentery in the +), and is actually the second most common cause of food'orne illness. Dysentery due to )higella usually occurs in daycare centers or other institutional settings. (Choice B! Enterohemorrhagic E. coli, especially E. coli 76?:8?, is a %ery important cause of colitis, and is classically transmitted 'y eating improperly cooed ground 'eef. (Choice D! Eating undercooed por puts a patient at an increased ris for the de%elopment of sporadic yersiniosis. (Choice E! In the +), Campylo'acter is one of the most freJuent causes of acute infectious diarrhea. The most common source of infection is undercooed infected poultry. atery or hemorrhagic diarrhea, along #ith se%ere a'dominal pain, is suggesti%e of the diagnosis.
Educational 0'*ecti%e: Diarrhea due to Fi'rio parahaemolyticus is usually transmitted 'y the ingestion of seafood (including shrimp, cra', and ra# oysters!.
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Q NO 115: A 7-ye!-ol" &oy $% &!o' o e o..$ce "'e o o+e-"y $%o!y o. .e1e!/ %o!e !o/ +" +'%e $% e#,e!'!e $% 3=9 C (892; :)/ &loo" ,!e%%'!e $% 889<79 ##/ ,'l%e $% 894<#$+/ +" !e%,$!$o+% !e 8><#$+ Te ,!y+5/ %o. ,le/ +" o+%$l% !e !e"/ %0olle+/ +" 0$ ,'!'le+ e5'"e% o+ e %'!.ce Te!e $% &$le!l e+"e! ce!1$cl ly#,"e+o,y Te !,$" "$+o%$c e% .o! %!e,ococcl +$e+ $% ,o%$$1e W $% e #o% ,,!o,!$e +e5 %e, $+ #+e#e+ A. B. C. D. E.
Throat culture Benathine penicillin G IF aJueous crystalline penicillin G 0ral clindamycin 0ral erythromycin
Explanation: This 'oy=s clinical features (e.g., a'rupt onset of high fe%er, inflamed tonsils and soft palate, purulent exudate, tender adenopathy! are suggesti%e of streptococcal pharyngitis. In such a setting, a positi%e rapid test for streptococcal antigen is sufficient to #arrant treatment #ith a single dose of I2 Benathine penicillin G. Although oral penicillin F is also accepta'le for streptococcal pharyngitis therapy, it is less preferred 'ecause it needs to 'e gi%en for much longer periods, and is thus more liely to 'e associated #ith medication nonadherence, especially once the patient=s symptoms a'ate. Erythromycin can 'e used as second line in penicillinallergic patients. (Choice A! hen the rapid test for streptococcal antigen is positi%e, there is no further need to o'tain a throat culture. (Choice C! IF crystalline penicillin 7 is used in cases of 'acterial meningitis and neurosyphilis.
Educational 0'*ecti%e: The treatment of choice for streptococcal pharyngitis is a single dose of I2 Benathine penicillin G or 7 day course of oral penicillin F. Erythromycin can 'e used as second line in penicillinallergic patients.
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Q NO 116: A 2;-ye!-ol" 0o#+ co#e% o e o..$ce +" co#,l$+% o. $+e!#$e+ "$66$+e%% +" + '+%e"y $ .o! e l% .e0 "y% e! %y#,o#% 0o!%e+ 0$ e5e!c$%e e! ,% #e"$cl $%o!y $% %$+$.$c+ .o! $+l$+ +" +'#&+e%% o. e! !$ .oo l%e" 3-4 "y% (8 ye! o)/ +" 1$%'l lo%% $+ e! !$ eye 0$c %,o++eo'%ly !e%ol1e" (3 ye!% o) Se $% c'!!e+ly +'!%$+ e! 2-#o+-ol" &&y e! o&%e!$cl $%o!y 0% '+co#,l$ce" e! +e'!olo$cl e5#$+$o+ %o0% !$ y,e!c$1e "ee, e+"o+ !e.le5e% O+ e#,e" le. 6e/ e! le. eye &"'c% +" e5$&$% o!$6o+l e!k +y%#'%/ &' e! !$ eye !e#$+% %$o+!y We+ %e e#,% o look o e !$/ e! !$ eye &"'c% +" e5$&$% o!$6o+l e!k +y%#'%/ &' e! le. eye !e#$+% %$o+!y Te ,$e+ $% &le o co+1e!e &o eye% oee!/ 0$o' +y %%oc$e" +y%#'% Te .c$l #'%cle% %o0 +o %$+% o. 0ek+e%% We!e $% e #o% l$kely %$e o. $% ,$e+% le%$o+ A. B. C. D. E. &. G. 8. I. L.
0ptic ner%e 0ptic tract 0ptic chiasma 0ptic radiations 0culomotor ner%e Trochlear ner%e A'ducent ner%e 2edial longitudinal fasciculus 2edial lemniscus &rontal eye field
Explanation: )uspect multiple sclerosis in a patient #ith neurological deficits that cannot 'e explained 'y a single lesion. Exacer'ation of these neurological deficits 'y hot #eather or exercise are a useful clue. Complete internuclear ophthalmoplegia (excellently descri'ed in this patient=s current eye mo%ement dysfunctions! is a pathognomonic finding, and is caused 'y demyelination of the medial longitudinal fasciculus in the dorsal pontine tegument. (Choice A! A lesion of the optic ner%e results in 'lindness of the same eye. (Choice C! A lesion of the optic chiasm results in 'lindness of 'oth eyes. (Choice D! A lesion of the optic radiation results in contralateral hemianopia. (Choice E! A lesion of the oculomotor ner%e results in ptosis and the eye looing do#n and out, due to unopposed actions of the lateral rectus and superior o'liJue muscles. (Choice &! A lesion of the trochlear ner%e results in %ertical diplopia and extorsion of eye. (Choice G! A lesion of the a'ducens ner%e results in con%ergent stra'ismus and horiontal diplopia. (Choice I! A lesion of the medial lemniscus affects touch and %i'ration sensations 'ilaterally. (Choice L! Destruction of the frontal lo'e causes ipsilateral de%iation of the e%es.
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Educational 0'*ecti%e: Internuclear ophthalmoplegia is a pathognomonic finding of multiple sclerosis, and is due to demyelination of the medial longitudinal fasciculus.
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Q NO 117: A 37-ye!-ol" #+ co#e% o $% ,!$# c!e ,y%$c$+ .o! e e1l'$o+ o. %l$ly ,!'!$$c %k$+ le%$o+% !o'+" $% +'% e "e+$e% .e1e!/ #l$%e/ +" +o!e5$ e $% %e5'lly c$1e 0$ #'l$,le #le ,!+e!% +" occ%$o+lly '%e% co+"o#% e % +e1e! &ee+ e%e" .o! I o! oe! %e5'lly !+%#$e" "$%e%e% e % +o "!' lle!$e% E5#$+$o+ %o0% %k$+-colo!e"/ 1e!!'co'%/ ,,$ll$.o!# le%$o+% !o'+" $% +'% W$c o. e .ollo0$+ $% e #o% ,,!o,!$e !e#e+ .o! $% ,$e+ A. B. C. D. E.
1odophyllin 1enicillin Erythromycin Doxycycline Tetracycline
Explanation: Condylomata acuminata (anogenital #arts! are caused 'y the human papilloma %irus. The characteristic lesions are %errucous, papilliform, and either sincolored or pin. This is in contrast to the lesions of condyloma lata, #hich are flat or %el%ety. )ystemic symptoms are usually a'sent. There are three treatment options for condyloma acuminata: . Chemical or physical agents (e.g., trichloroacetic acid, 6 florouracil epinephrine gel, and podophyllin! ". Immune therapy (e.g., imiJuimod, interferon alpha! $. )urge (e.g., cryosurgery, excisional procedures, laser treatment! The choice of treatment depends upon the num'er and extent of lesions. 1odophyllin is a topical antimitotic agent that leads to cell death. It is teratogenic and thus contraindicated in pregnancy. Its other ad%erse effects include local irritation and ulceration. (Choices B, C, D, and E! Condyloma lata are flat or %el%ety lesions. They are indicati%e of secondary syphilis for #hich the treatment of choice is penicillin. If the patient is allergic to penicillin, tetracycline or doxycycline is gi%en. If the patient is pregnant, erythromycin is used.
Educational 0'*ecti%e: Condylomata acuminata are %errucous, papilliform lesions located in the anogenital region. 1odophyllin is one of the a%aila'le treatment options.
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Q NO 118: A 39-ye!-ol" 0$e #le $1e% $%o!y o. .eel$+ .$'e" e%$ly e %e% e 0% 1e!y e+e!e$c +" ely "'!$+ $% collee "y%/ &' .o! e ,% .e0 ye!%/ Ge1e!y$+ %ee#% o &e o$+ 0!o+H e e% ,oo!ly +" % lo% .e0 ,o'+"% o1e! e l% !ee ye!% Te ,$e+ l%o %lee,% e5ce%%$1ely +$ +" !e,o!% "$#$+$%e" &$l$y o co+ce+!e $+ +y c$1$y $% .!$e+"% .!e'e+ly !e#!k o+ o0 '+,,y e look% ll e $#e/ +" e "e%,e!ely .eel% e +ee" .o! ,%yc$!$c el, B%e" o+ e &o1e ,!e%e+$o+/ 0 $% e #o% l$kely "$+o%$% A. B. C. D. E.
Ad*ustment disorder Dysthymia 2a*or depression Generalied anxiety disorder )u'stance induced mood disorder
Explanation: D)2IF defines dysthymia as a depressed mood for most of the day for at least t#o years. Additional features are t#o or more of: decreased or increased appetite, poor energy, insomnia or hypersomnia, impaired concentration, lo# self esteem, and feelings of #orthlessness. (Choice A! Ad*ustment disorder is characteried 'y the presence of mood or 'eha%ioral symptoms in the setting of a recent stressor. The symptoms are in excess of #hat #ould 'e expected from the specific stressor and usually occur #ithin three months of the onset of the stressor. (Choice C! This patient gi%es a history of depressi%e symptoms for the past three years. #hich maes dysthymia a more liely diagnosis than ma*or depression. Although patients #ith dysthymia present similar to ma*or depression, the symptoms tend to 'e less se%ere. (Choice D! Generalied anxiety disorder is characteried 'y uncontrolla'le #orry o%er a num'er of different e%ents or acti%ities. 0ther features are sleep distur'ances, fatigue, irrita'ility, and poor concentration. eight loss is nota feature. (Choice E! Although su'stanceinduced mood disorder is a possi'ility, there is not much e%idence for the same in the history gi%en a'o%e.
Educational 0'*ecti%e: Dysthymia P depressed mood for most days for at least t#o years.
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Q NO 119: A 39-ye!-ol" Sc+"$+1$+ .e#le ,!e%e+% 0$ 2 0eek% $%o!y o. &$le!l +kle ,$+ Se l%o !e,o!% .e1e!/ e%y .$&$l$y/ +" lo%% o. ,,e$e O+ e5#$+$o+/ %e % &$le!l e+"e! c'+eo'% +o"'le% o1e! e +e!$o! %'!.ce o. e le% e! ce%-J !y !e1el% &$le!l $l! ly#,"e+o,y L&o!o!y e%% %o0 ele1e" ESR/ #$l" ele1$o+ o. !e'#o$" .co! +" ,o%$$1e +$+'cle! +$&o"$e% E5#$+$o+ o. oe! %y%e#% $% '+!e#!k&le e! 1$l% !e %&le e5ce, e#,e!'!e o. === : W $% e #o% l$kely "$+o%$% A. B. C. D. E. &. G.
9ofgren=s syndrome. 8eerfordtaldenstrom syndrome. Chronic sarcoidosis. Tu'erculosis. 8odgin=s lymphoma. heumatoid arthritis. )ystemic lupus erythematosus.
Explanation: )arcoidosis is 'asically t#o types: Acute and chronic. 9ofgren=s syndrome is an acute form of sarcoidosis predominantly seen in )candina%ian, Irish, and 1uerto ican #oman. The characteristic presentation consists of triad of arthritis (of anles, nees, #rists or el'o#s!, erythema nodosum and 'ilateral hilar adenopathy. 9ung in%ol%ement is %ery rare in this acute form. 9a'oratory studies suggest inflammatory disease #ith ele%ated E)I false positi%e rheumatoid factor, and antinuclear anti'odies. Choice (B!: 8eerfordtaldenstrom syndrome is another rare from of acute sarcoidosis consists of fe%er, parotid enlargement, anterior u%eitis, and facial ner%e palsy. Choice (C!: Chronic sarcoidosis has an insidious on set that de%elops o%er months. It mainly presents #ith respiratory complaints #ithout constitutional symptoms. Fery fe# patients ha%e organs other than lung in%ol%ed. It leads to permanent lung damage. Choice (D!: Tu'erculosis presents #ith constitutional symptoms such as fatigue, #eight loss, anorexia, lo#grade fe%er and night s#eats. 1ulmonary symptoms include cough, #ith purulent sputum or hemoptysis. Chest N ray re%eals hilar and mediastinal lymphadenopathy, small infiltrates, pleural effusion and segmental atelectasis. Bilateral anle arthritis is not a future of tu'erculosis (TB!. Choice (E!: 8odgin=s lymphoma usually presents #ith fe%er, #eight loss, night s#eats, and generalied pruritus. These patients ha%e painless lymphadenopathy that 'ecomes painful #ith alcohol ingestion. Again, this acute presentation is classic for acute sarcoidosis. Choice (&!: heumatoid arthritis is associated #ith systemic symptoms such as fe%er, malaise, and #eight loss. 2orning *oint stiffness lasting for more than $7 minutes is a characteristic feature. They usually in%ol%e metacarpophalangeal *oints (2C1! and proximal interphalangeal *oints (1I1! in%ol%ement. The *oints are symmetrically in%ol%ed and ha%e o'%ious signs of inflammation. E) is al#ays ele%ated. Bilateral hilar lymphadenopathy is not classic for systemic lupus erythematosus ()9E!. Choice (G! )ystemic lupus erythematosus presents #ith fe%er, malaise, and #eight loss. These patients ha%e a characteristic 'utterfly rash 138
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o%er the face. 2a*ority of patients ha%e *oint symptoms usually non de'ilitating. )erologic findings include anti nuclear anti'ody #ith high titer to nati%e D4A. Bilateral hilar lymphadenopathy is not classic for )9E. Educational 0'*ecti%e: 9ofgren=s syndrome is an acute form of sarcoidosis and consists of triad of 'ilateral anle arthritis (sometimes nees, #rists or el'o#s!, erythema nodosum and 'ilateral hilar adenopathy.
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Q NO 120: A !o', o. $+1e%$o!% !e ,l++$+ o co+"'c %'"y o %%e%% e !el$o+%$, &e0ee+ colo+ c+ce! +" ele1e" ,l%# C!ec$1e ,!oe$+ (CRP) le1el Tey 0+ o co#,!e e #e%'!e" ,l%# CRP le1el% o. ,$e+% 0$ +" 0$o' colo+ c+ce! W$c o. e .ollo0$+ $% e &e% %e#e+ o. e +'ll y,oe%$% .o! $% %'"y A. The ris of colon cancer is the same for the su'*ects #ith and #ithout ele%ated plasma C1 le%els B. There is no association 'et#een ele%ated plasma C1 le%el and colon cancer C. )u'*ects #ith ele%ated plasma C1 le%el are prone to colon cancer D. Colon cancer does not affect plasma C1 le%el E. Colon cancer is more pre%alent among su'*ects #ith ele%ated C1 le%el Explanation: To state the null hypothesis correctly, the study design must 'e considered. In this case, the study is crosssectional. The t#o %aria'les 'eing studied (i.e., ele%ated plasma C1 le%el and colon cancer! are measured at the same time, so the temporal relationship 'et#een these t#o cannot 'e determined. Another point is that the null hypothesis is al#ays the statement of no relationshipS In this case, the correct null hypothesis should state that there is no association 'et#een ele%ated plasma C1 le%els and colon cancer. (Choice A! This is a good statement of the null hypothesis for a cohort study. (Choices C and D! In crosssectional studies, the temporal relationship of the %aria'les 'eing studied cannot 'e determined (i.e., #hether the exposure preceded the outcome, or #hether the outcome preceded the exposure!. The ris for either %aria'le cannot 'e determined as #ell. (Choice E!The alternati%e hypothesis opposes the null hypothesis. It states that there is a relationship 'et#een the exposure and outcome.
Educational 0'*ecti%e: The null hypothesis is al#ays the statement of no relationship 'et#een the exposure and the outcome. To state the null hypothesis correctly, you should recognie the study design first.
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Q NO 121: A >8-ye!-ol" #+ ,!e%e+% o yo'! o..$ce 0$ 0o-0eek $%o!y o. lo0 &ck ,$+ e "e%c!$&e% e ,$+ % co+%+/ "'ll/ +" c$+ I $% +o+-!"$$+ Te ,$+ $% +o ..ece" &y #o1e#e+ +" c++o &e .'lly !el$e1e" &y ly$+ "o0+ e "e+$e% .e1e! +" '!$+!y .!e'e+cy o! e%$+cy e % %!e" k$+ %lee,$+ ,$ll% &ec'%e e ,$+ "$%'!&% $# "'!$+ e +$ O+ ,y%$cl e5#$+$o+/ e ,!%,$+l #'%cle% !e +o+-e+"e! Pe!c'%%$o+ o1e! e l'#&! 1e!e&!e "oe% +o el$c$ e+"e!+e%% K+ee !e.le5e% !e %y##e!$c +" e % ;<; %!e+ $+ e e5!e#$$e% &$le!lly A %!$ le !$%e e% $% +e$1e W$c o. e .ollo0$+ $% e &e% e% .o! $% ,$e+ A. B. C. D. E. &.
Electromyography 89A genotyping +rethral cultures 1rostatespecific antigen (1)A! A'dominal ultrasonography )erum 1T8 le%el
Explanation: This patient has symptoms concerning for primary 'one cancer or metastasis to the 'one. )ymptoms that #ould raise a red flag for cancer include pain not relie%ed 'y rest, pain at night, constant or dull pain, fe%ers, lac of exacer'ation #ith mo%ement, and presence of neurologic changes. Cancer pain is often not tender to palpation. The most common cancers that metastasie to the 'one are lung, 'reast, prostate, renal, and thyroid. 0f these possi'ilities, prostate cancer is most liely in a ;yearold man, so o'taining a 1)A #ould 'e a reasona'le next step. (Choice A! Electromyography (E2G! can 'e helpful in distinguishing 'et#een ner%e and muscle disease. This patient does not ha%e findings suggesti%e of either of these, scan E2G is unliely to aid in diagnosis. (Choice B! Anylosing spondylitis is characteried 'y progressi%e limitation of 'ac motion and chest expansion. It most often occurs in young men (O37 years old!. )ymptoms, #hich include 'ac pain and stiffness, are typically #orst in the morning and impro%e as the day progresses. Nrays #ill sho# changes characteristic of sacroiliitis. This patient=s presentation is not consistent #ith anylosing spondylitis. (Choice C! This patient does not ha%e fe%er or urinary symptoms to suggest a urethral infection. (Choice E! A'dominal ultrasonography is helpful to e%aluate for hydronephrosis and 'ladder distention. Bladder distention is more liely to cause suprapu'ic rather than 'ac pain. (Choice &! 1atients #ith prostate cancer can de%elop hypercalcemia. hen this occurs, 1T8 le%els #ill 'e suppressed. 8o#e%er, not all prostate cancer patients #ill ha%e sufficient hypercalcemia to suppress 1T8, so this is not a relia'le diagnostic test. Education 0'*ecti%e: Bac pain is one of the most common complaints in adult medicine. Itis important to identify signs that suggest a serious etiology, such as pain not relie%ed 'y rest, night pain, constant or dull pain, fe%ers, lac of exacer'ation #ith mo%ement or palpation, and presence of neurologic changes.
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Q NO 122: A 3;-ye!-ol" #le ,!e%e+% o e .#$ly ,y%$c$+ .o! &$le!l y+eco#%$ e o&%e!1e" ,!o!e%%$1e $+c!e%e $+ $% &!e% %$6e %!$+ > #o+% o e $% %e5'lly c$1e +" "e+$e% +y "!' '%e Py%$cl e5#$+$o+ !e1el% &$le!l y+eco#%$ +" e+"e!+e%% Te e+$o'!$+!y e5#$+$o+ %o0% 8 c# +o"'le $+ e !$ e%$% Oe!0$%e/ e e5#$+$o+ $% 0$$+ +o!#l l$#$% Te l&o!o!y !e,o! %o0% L 3 U9 ,<#L)/ &e CF '+"eec&le/ A:P '+"eec&le W$c $% e #o% l$kely "$+o%$% A. B. C. D. E.
9eydig cell tumor Choriocarcinoma Teratoma )eminoma Endodermal sinus tumor
Explanation: 9eydig cell tumors (Choice A! are the most common type of testicular sex cord stromal tumors, #hich may occur in all age groups, including young children. 9eydig cells are the principal source of testosterone and are capa'le of estrogen production, due to maredly increased aromatase expression. The estrogen production is maredly increased in tumorous gro#th of 9eydig cells, #ith secondary inhi'ition of 98 and E)8 le%els. Endocrine manifestations are found in only "7 to $7 percent of adults, the most common 'eing gynecomastia, ho#e%er in prepu'ertal cases, precocious pu'erty is common. Choriocarcinoma (Choice B! is a germ cell tumor characteried 'y increased serum 'eta8CG concentration. In teratomas (Choice C!, ele%ations in the serum concentration of AE1 or 'etahCG can appear, #hich cannot 'e attri'uted to teratomatous element, ho#e%er they indicate the coexistence of other germ cell tumor components. In seminomas (Choice D! serum tumor marers are usually normal, although 'etahCG may 'e some#hat ele%ated #ith seminomas that contain syncytiotropho'lastic giant cells. Rol sac tumor (endodermal sinus tumor! (Choice E! is a germ cell tumor accompanied 'y an increase in serum AE1.
Educational o'*ecti%e: In 9eydig cell tumors, the estrogen production can 'e increased #ith secondary inhi'ition of 98 and E)8.
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Q NO 123: A 8;-ye!-ol" &oy co#e% o e ,y%$c$+ &ec'%e o. e#'!$ +" lo0e! &"o#$+l ,$+ T$% $% $% $!" e,$%o"e o. e#'!$ $+ e ,% 2 ye!% e % .#$ly $%o!y o. !e+l "$%e%e $% e#,e!'!e $% 378 C (=?= :)/ &loo" ,!e%%'!e $% 849<=9 ## / ,'l%e $% ?9<#$+/ +" !e%,$!$o+% !e 84<#$+ E5#$+$o+ %o0% #$l" %e+%o!$+e'!l "e.+e%% &$le!lly U!$+ly%$% %o0% e#'!$ +" ,!oe$+'!$ L&o!o!y %'"$e% %o0 BUN o. ;9 #<"L +" %e!'# c!e$+$+e o. 38 #<"L@ %e!'# co#,le#e+ le1el% !e +o!#l Re+l &$o,%y %o0% .o# cell%/ +" $##'+o.l'o!e%ce+ce %o0% +o $##'+olo&'l$+% o! co#,le#e+ Elec!o+ #$c!o%co,y %o0% le!+$+ !e% o. $++e" +" $cke+e" c,$ll!y loo,% 0$ %,l$$+ o. FBM W$c o. e .ollo0$+ $% e #o% l$kely "$+o%$% A. B. C. D. E. &. G. 8. I. L. <. 9. 2. 4.
Alport=s syndrome Acute interstitial nephritis Acute post infectious glomerulonephritis Antiglomerular 'asement mem'rane disease Benign recurrent hematuria Good pasture=s syndrome 8enoch)chonlein purpura Idiopathic antiGB2 anti'ody mediated glomerulonephritis IgA nephropathy 2ixed essential cryoglo'ulinemia 2icroscopic polyangiitis )ystemic lupus erythematosus Thin 'asement mem'rane disease egener=s granulomatosis
Explanation: The a'o%e %ignette illustrated the classic presentation of Alport=s syndrome. This is a familial disorder #hich usually presents in childhood as recurrent gross hematuria and proteinuria. )ensorineural deafness usually occurs. Electron microscopy findings include alternating areas of thinned and thicened capillary loops #ith splitting of the glomerular 'asement mem'rane (GB2!. (Choice 2! Thin 'asement mem'rane disease is also a familial disorder, 'ut it presents in adulthood as microscopic hematuria #ithout proteinuria. enal 'iopsy re%eals a maredly thinned 'asement mem'rane. (Choice E! Benign recurrent hematuria is asymptomatic. enal 'iopsy is normal in most cases. This condition has an excellent prognosis.
Educational 0'*ecti%e: )uspect Alport=s syndrome in patients #ith recurrent episodes of hematuria, sensorineural deafness and a family hi sto# of renal failure.
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Q NO 124: A ;3-ye!-ol" C'c%$+ #+ co#e% o e e#e!e+cy "e,!#e+ 2 # &ec'%e o. %e1e!e ,$+ $+ $% !$ !e oe .o! e ,% 2 o'!% e co#,l$+% e ,$+ &e+ %'""e+ly % "'ll/ c$+ ,$+/ +" % 0o!%e+e" o1e! $#e o %e1e!e !o&&$+ ,$+/ +o !el$e1e" &y ce#$+o,e+ $% oe! #e"$cl ,!o&le#% $+cl'"e y,e!e+%$o+/ "$&ee% #ell$'%-y,e 2/ y,e!cole%e!ole#$/ +" ,e,$c 'lce! "$%e%e e % %#oke" 2 ,ck% o. c$!ee% "$ly .o! 39 ye!% e "!$+k% ;-> o'+ce% o. lcool "$ly e e% lo o. '+k .oo" +" e5e!c$%e% $+.!e'e+ly Bo $% .e! +" #oe! 1e "$&ee% +" y,e!e+%$o+ $% ol"e! &!oe! "$e" o. #yoc!"$l $+.!c$o+ 2 ye!% o $% #e"$c$o+% $+cl'"e ly&'!$"e/ l$%$+o,!$l/ e+olol/ %$#1%$+ +" .#o$"$+e $% e#,e!'!e $% 37? C (899 :)/ &loo" ,!e%%'!e $% 8>9<=9## / ,'l%e $% ??<#$+ +" !e%,$!$o+% !e 8><#$+ O+ e5#$+$o+/ e !$ !e oe ,,e!% #!ke"ly %0olle+/ !e"/ +" $% 0!# o o'c A%,$!$o+ o. e o$+ .l'$" !e1el% +e$1ely &$!e.!$+e+ +ee"le %,e" c!y%l% A ,! .!o# ,!e%c!$&$+ o!l $+"o#ec$+/ 0 oe! $+e!1e+$o+ 0o'l" &e #o% $#,o!+ o ,!e1e+ e "e1elo,#e+ o. .'!e! ck%
A.
)moing cessation B. Alcohol cessation C. )topping lisinopril D. )topping sim%astatin E. )topping gly'uride &. )topping famotidine G. egular exercise and a healthy diet Explanation: Accumulation of urate crystals in the syno%ial fluid causes inflammation of the syno%ial lining, and precipitates an acute attac of gout. The attacs often occur at night. The most common *oint affected is the first metatarsophalangeal *oint. Chronic alcoholism is a ris factor for the de%elopment of gout. Ethanol is meta'olied to lactate, #hich competes #ith urate for renal excretion, leading to accumulation of urate in the 'ody. Cessation of alcohol plays an important role in pre%ention of future attacs, especially in chronic alcoholics. 0ther measures that should 'e o'ser%ed 'y patients #ith gout are (! staying on a lo# purine diet, and ("! a%oiding drugs such as diuretics and pyrainamide. Treatment of an acute attac is #ith 4)AID) (drug of choice!, colchicine or steroids. )moing cessation (Choice A!, regular exercise, and a healthy diet (Choice C! #ill 'enefit this patient 'y pre%enting coronary artery disease, especially since he has a history of hypertension, dia'etes and hypercholesterolemia, along #ith a strong family history. 8o#e%er, alcohol cessation is still the most important inter%ention that #ill help in pre%enting future attacs of gout in this patient. 9isinopril, gly'uride, famotidine and sim%astatin (Choices C, D, E and &! are not associated #ith gouty attacs. Educational 0'*ecti%e:
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Cessation of alcohol and staying on a lo# purine diet are important measures in the pre%ention of future attacs in patients #ith acute gouty arthritis. Extremely high yield Juestion for the +)29ESSS
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Q NO 125: A 32-ye!-ol" co#,+y e5ec'$1e ,!e%e+% 0$ "$%co#.o! $+ $% !$ cl. "'!$+ 0lk Te ,!o&le# %!e" 3 "y% o +" $% cco#,+$e" &y ,$+ $+ $% .ee !e%/ e%,ec$lly "'!$+ e +$ e % &ee+ 1$+ %$#$l! ,!o&le#% o1e! e ,% > #o+% &' e $% e$+ 0o!%e "y &y "y e % %#oke" ,ck o. c$!ee%<"y .o! e ,% 82 ye!% E5#$+$o+ o. e lo0e! l$#&% !e1el +o!#l .e#o!l ,'l%e &' "$#$+$%e" ,o,l$el/ ,o%e!$o! $&$l +" "o!%l$% ,e"$% ,'l%e% o+ e !$ %$"e Le. %$"e ,'l%e% !e +o!#l Te!e $% l%o e1$"e+ce o. %#ll !e" e+"e! co!"% o+ e #e"$l %,ec o. $% !$ cl. $% !$ le ,,e!% ,le +" col" Te!e $% e1$"e+ce o. "$#$+$%e" %e+%$o+% o+ e !$ %$"e/ % co#,!e" o e le. A+kle +" k+ee !e.le5e% !e $+c P!e1$o'% $%o!y $% $+%$+$.$c+ BP $% 849<=9## +" PR $% ?9<#$+ e! +" l'+ e5#$+$o+ $% '+!e#!k&le W $% e #o% l$kely "$+o%$% A. B. C. D. E.
Buerger=s disease Berger=s disease Atherosclerotic disease Cholesterol atheroem'oli Taayasu=s arteritis
Explanation: Explanation: This is a classic presentation of Buerger=s Disease. It is an episodic, and segmental inflammatory process of small and medium sied arteries (throm'oangiitis o'literans!. It is characteried 'y occlusi%e disease of the arteries, migratory superficial throm'ophle'itis, and aynaud=s phenomenon. +sually one or t#o of these three conditions are present. 0ther important features are young age, males and history of smoing. Cessation of smoing is an important component of management. Berger=s Disease is a distracter. It is the other name of IgA nephropathy. This patient has no renal symptoms, so it can 'e ignored. Atherosclerotic disease is a good distracter and you should 'e a'le to differentiate 'et#een the t#o. This patient is young, and has features suggesti%e of occlusi%e disease. In older patients, e%idence of migratory superficial throm'ophle'itis and presence of persistent symptoms can 'e helpful. Atheroem'olism of atherothrom'otic de'ris from a proximal source to small terminal arteries may'e secondary to any in%asi%e arterial procedure or spontaneous. )ymptoms are %aria'le according to the site in%ol%ed ho#e%er, #hen in%ol%ing the lo#er extremities it has also 'een called -'lue toe syndrome/. 1ulses are usually normal and help to differentiate from atherosclerotic disease. 9i%edo reticularis in the sin o%erlying the calf muscles may 'e present. 9a'oratory findings may sho# eosinophilia, and an ele%ated E). Taayasu=s arteritis (1ulseless disease! is of unno#n cause, and usually in%ol%es 'ranches of the aortic arch. The symptoms caused 'y this disease are caused 'y cere'ro%ascular insufficiency, such as a'sent pulses in upper lim' and nec 'ruit. Educational 0'*ecti%e:
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(INTERNAL MEDICINE) *Block
The triad of occlusi%e disease of the arteries, migratory superficial throm'ophle'itis, and aynaud=s phenomenon in a smoer male is classic of Buerger=s Disease.
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Q NO 126: A 37-ye!-ol" ely C'c%$+ #le $% %ee+ $+ yo'! o..$ce .o! !o'$+e ,y%$cl e5#$+$o+ e "e+$e% +y %y#,o#% o! $ll+e%% e %y% e %#oke% ,ck "y +" "!$+k% o+e o 0o &ee!% e1e!y 0eeke+" e % +o lle!$e% E5#$+$o+ $% '+!e#!k&le Te EKF !e1el% +o!#l %$+'% !y# 0$ e! !e o. 72@ e!e !e .!e'e+ ,!e#'!e !$l &e% ,!e%e+ Te &loo" ,!e%%'!e $% 829<>;## Te +e5 %e, $+ $% #+e#e+ $% A. B. C. D. E.
Digoxin 9idocaine 0rder potassium le%els Complete electrophysiological study 0'ser%ation
Explanation: The diagnosis of atrial premature 'eats depends upon the recognition of K1 #a%es that are premature relati%e to sinus cycle length and #hich differ in morphology from sinus K1= #a%es. Atrial premature 'eats freJuently reset the sinus node, producing pauses, #hich are only partially compensatory. The ) #idth is normal. 1remature atrial 'eats may 'e completely normal or due to anxiety, C8&, hypoxia, caffeine or electrolyte a'normalities. 1remature atrial 'eats ne%er reJuire any treatment and are completely 'enign (0ption E!. (0ption A!: Digoxin is a classic inotrope, #hich is freJuently used in the treatment of atrial arrhythmias, especially fi'rillation. It increases the AF nodal refractoriness and there'y slo#s the %entricular rate in atrial fi'rillation and flutter. Digoxin is particularly used in patients #ith heart failure (systolic dysfunction! and atrial fi'rillationflutter. Digoxin has no role in the management of premature atrial 'eats. (0ption B!: 9idocaine is a class anti arrhythmic agent used in the treatment of %entricular arrhythmias. It has no role in the treatment of atrial arrhythmias. The drug is usually gi%en intra%enously. (0ption C!: arely premature atrial 'eats may 'e due to electrolyte a'normalities. In such cases, le%els of potassium, magnesium and calcium may need to 'e e%aluated. emo%ing the causati%e agent or replacing the deficient electrolyte can treat premature atrial 'eats. Electrolyte a'normalities are unliely in a healthy patient #ithout comor'id illnesses. (0ption D!: Electrophysiological study can esta'lish #hether an anomalous path#ay is present or a'sent and allo# its localiation. 1remature atrial 'eats do not ha%e an anatomical distur'ance and E1 studies are not helpful at all.
Educational o'*ecti%e: 1remature atrial 'eats are 'enign and neither reJuire any follo#up nor treatment.
148
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(INTERNAL MEDICINE) *Block
Q NO 127: A 4;-ye!-ol" .e#le ,!e%e+% o e#e!e+cy !oo# co#,l$+$+ o. '!$+!y .!e'e+cy/ &'!+$+ "'!$+ '!$+$o+/ +" 0ek+e%% e! l% #e+%!'l ,e!$o" 0% o+e ye! o/ +" %e $% +o %e5'lly c$1e Se $% +o k$+ +y #e"$c$o+% e! e#,e!'!e $% 37? C (899 :)/ &loo" ,!e%%'!e $% 829<7> ##/ ,'l%e $% ?9<#$+/ +" !e%,$!$o+% !e 84<#$+ e!y #$l" co%o1e!e&!l +le e+"e!+e%% $% ,!e%e+ I ce.!$5o+e $% %!e" T0o "y% le!/ e ,$e+ .eel% #'c &ee! A+$&$o$c %'%ce,$&$l$y e%$+ !e'!+e" 0$ + '!o,oe+ (E col$) $ly %e+%$$1e o ce.!$5o+e/ e+#yc$+/ c$,!o.lo5c$+ +" !$#eo,!$#<%'l.#eo56ole (TMP
Add ciprofloxacin to the regimen )#itch to T21)2N )#itch to gentamycin Continue ceftriaxone Discontinue anti'iotic therapy
Explanation: This patient has signs and symptoms suggesti%e of uncomplicated pyelonephritis. It seems that the condition responded to parenteral anti'iotic therapy. The patients #ith uncomplicated pyelonephritis can 'e usually s#itched to an oral anti'iotic after 3>?" hours of parenteral therapy (Choice D!. At this point, the most reasona'le step is to s#itch to an oral anti'iotic chosen according to the anti'iotic suscepti'ility testing. T21)2N is a good choice 'ecause it is relati%ely cheap. The a%erage duration of anti'iotic therapy during uncomplicated pyelonephritis is t#o #ees (Choice E!. There is no reason to add another anti'iotic (Choice A! or s#itch to another parenteral agent (Choice C!.
Educational 0'*ecti%e: After 3>?" hours of parenteral therapy for uncomplicated pyelonephritis the patient can 'e usually s#itched to an oral agent. 0ral therapy is more con%enient and less expensi%e5 if the results of anti'iotic suscepti'ility testing are no#n, the appropriate anti'iotic can 'e easily chosen. Extremely high yield Juestion for +)29ESSS
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(INTERNAL MEDICINE) *Block
Q NO 128: A 4;-ye!-ol" %#$c ,$e+ co#e% o yo' .o! !o'$+e ceck', e $% k$+ lo0-"o%e &eclo#e%o+e $+le! "$ly +" $+le" %l&'#ol/ % +ee"e"/ .o! !ee #o+% e $% 1e!y ,,!ee+%$1e &o' e '%e o. %e!o$"% +" %k% yo' $. e $% !$%k o. +y co#,l$c$o+ .!o# e lo0-"o%e $+le" &eclo#e%o+e W$c o. e .ollo0$+ $% e #o% l$kely co#,l$c$o+ o. lo0-"o%e $+le! &eclo#e%o+e '%e A. B. C. D. E. &.
Cushing=s syndrome Thrush 0steoporosis Adrenal suppression 1urpura Cataract formation
Explanation: Inhaled corticosteroids are indicated in patients #ith persistent symptoms from asthma. The agents currently a%aila'le in the +nited )tates are 'eclomethasone, 'udesonide, flunisolide, fluticasone propionate and triamcinolone acetonide. In adults, the ad%erse effect of lo#dose inhaled corticosteroid are limited to topical pro'lems such as dysphonia, #hich occurs in 67 percent of patients and oral candidiasis5 symptomatic in less than 6 percent. 8igh doses of inhaled corticosteroids can lead to increased systemic a'sorption and can produce adrenal suppression, cataract formation, decreased gro#th in children, interference #ith 'one meta'olism and purpura. 8o#e%er, these systemic effects are dosedependent and occur in patients #ho are on highdose inhaled steroids for prolonged period of time.
Educational 0'*ecti%e: Ad%erse effects of lo#dose inhaled corticosteroids are limited to topical pro'lems lie dysphonia and thrush. 8o#e%er, systemic toxicity may occur in patients #ho are on highdose inhaled steroids for prolonged periods of time.
150
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(INTERNAL MEDICINE) *Block
Q NO 129: A ;"yearold man comes to the office and complains of increasing fatigue and #eaness for the last 3 months. 8e also descri'es a dull pain in his 'ac and arms, #hich gets #orse #ith #aling. 8e denies any num'ness or paresthesia. 0n examination, he appears pale. There is tenderness around the lum'ar spine. CBC re%eals: BC >,;77 mm$ #ith normal differential 8emoglo'in >.; gd9 8ematocrit "? 1latelets ;3,777 mm$ The BC morphology is significant for a rouleaux appearance. The E) is 66mmhr. Bence Lones proteins are identified in the urine. hich of the follo#ing is expected in this patients 'one marro# examination
A. B. C. D. E.
0%er proliferation of plasma cells Increased marro# cellularity #ith megaaryocytic hyperplasia 8ypoplastic fatfilled marro# #ith no a'normal cells 4ormocellular 'one marro# 8ypocellular and fi'rotic 'one marro#
Explanation: The patient=s diagnosis is multiple myeloma (22!. 22 is caused 'y the proliferation of a single transformed plasma cell usually producing lgG. Classical findings are: .9ytic 'one lesions ". 2arro# plasmacytosis $. +rine and serum monoclonal proteins 22 presents in old age. Bac pain is the most common manifestation. ecurrent infections are also common. The complete #orup consists of CBC #ith differential and morphology, serum electrolytes, idney and li%er screening profiles, seletal sur%ey, and serum electrophoresis, and 'one marro# 'iopsy. Complications include renal failure, hypercalcemia, and hyper%iscosity syndrome. (Choice B! Increased marro# cellularity #ith megaaryocytic hyperplasia is seen in essential throm'ocytopenia. (Choice C! Aplastic anemia sho#s hypoplastic fatfilled marro# #ith no a'normal cells. (Choice E! 8ypocellular and fi'rotic 'one marro# is seen in myelofi'rotic disorders.
Educational 0'*ecti%e: 2ultiple myeloma is a plasma cell disorder #hich often presents #ith lytic lesions, hypercalcemia, and renal failure.
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(INTERNAL MEDICINE) *Block
Q NO 130: A 42-ye!-ol" #le co#e% o yo' 0$ e co#,l$+% o. yello0 '!$+e +" yello0 "$%colo!$o+ o. e1e% $% ,% #e"$cl $%o!y $% $+%$+$.$c+ +" e ke% +o #e"$c$o+ O+ e5#$+$o+ e % Te#,e!'!e 37 C (=?> :)/ RR 82<#$+/ PR ?9<#$+/ +" $ce!$c %cle!e $% l$1e! .'+c$o+ e%% %o0 ol &$l$!'&$+ 889 #<"l/ "$!ec &$l$!'&$+ ?9 #<"l/ AST 4; IU
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 131: A ;7-ye!-ol" #+ co#e% o e ,y%$c$+ &ec'%e o. 2 e,$%o"e% o. e#o,y%$% e l%o co#,l$+% o. co'/ .$'e +" .e1e! .o! %e1e!l "y% e % %#oke" 0o ,ck% o. c$!ee% "$ly .o! 2; ye!% e "oe% +o '%e lcool o! "!'% $l %$+% !e %&le E5#$+$o+ %o0% le.-%$"e" 1!$cocele 0$c .$l% o e#,y 0e+ e ,$e+ $% !ec'#&e+@ e5#$+$o+ oe!0$%e %o0% +o &+o!#l$$e% L&o!o!y %'"$e% %o0 & o. 8>2 <"L +" ,lele% o. 4?9/999
A.
Chest xray B. A'dominal CT scan C. +rinalysis D. )erum alfafetoprotein le%els E. +ltrasonogram of the testicles Explanation: This patient most liely has renal cell carcinoma (CC!. 2ost of the patients #ith CC are asymptomatic until the disease is ad%anced. The classic triad of CC (flan pain, hematuria, and a palpa'le a'dominal renal mass! is uncommon (7 of patients!5 #hen present, it strongly suggests ad%ancedmetastatic disease. 8ematuria is seen only in a'out 37 of patients. )crotal %aricocele, (the ma*ority are on leftside!, may'e o'ser%ed in a fe# patients (O7!. Faricoceles typically fail to empty #hen the patient is recum'ent. 1resence of this finding should al#ays raise suspicion for a renal cell carcinoma, #hich is most commonly due to o'struction of the gonadal %ein #here it enters the renal %ein. "7 of patients may also ha%e constitutional symptoms lie fe%er, night s#eats, anorexia, #eight loss, or an easy fatiga'ility. Increased erythropoietin 'y idney mass can produce polycythemia and throm'ocytosis. (Choice B! CT scan of the a'domen is most sensiti%e and specific for diagnosing the renal cell carcinoma and should 'e o'tained #hen the index of suspicion is high. (Choice A! Chest xray is an important in%estigation to loo for metastasis 'ut is not going to re%eal the diagnosis in this patient. (Choice C! +rinalysis may detect hematuria 'ut it is nonspecific and only 37 of patients #ith renal cell carcinoma ha%e hematuria. (Choices D and E! These findings are unliely #ith testicular carcinoma5 therefore, an +)G of the testicles or serum alpha fetoprotein are not reJuired in this patient.
Educational 0'*ecti%e: Faricoceles that fail to empty #hen the patient is recum'ent raises the suspicion for renal cell carcinoma. CT scan of the a'domen is most sensiti%e and specific for diagnosing the renal cell carcinoma.
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(INTERNAL MEDICINE) *Block
Q NO 132: A $6yearold Caucasian male presents #ith #eaness, fatigue, and #eight loss o%er the past year. 8e is anorexic and has lost interest in all his acti%ities. 8is 'lood pressure is @>?7mm 8g, temperature is $?. C (@@ &!, respirations are 3min, and pulse is ?3min. 0n physical examination, he is irrita'le and restless. Dar 'ro#n pigmentation is present on his sin creases and oral ca%ity mucous mem'ranes. 9a'oratory studies sho#: 8emoglo'in 7.$ gd9 BC count $,777micro9 4eutrophils ;7 2onocytes 6 Eosinophils 7 Basophils 9ymphocytes "3 )erum sodium $7 meJ9 )erum potassium 6.6 meJ9 Chest xray and 11D tests are normal. hat is the most appropriate next step in the management of this patient
A. B. C. D. E.
"3 hour urinary free cortisol 9o#dose o%ernight dexamethasone suppression test Cosyntropin stimulation test 2easure plasma ACT8 le%el Begin hydrocortisone
Explanation: 1rimary adrenocortical insufficiency (Addison=s disease! is caused 'y destruction of the adrenal cortex, usually 'y an autoimmune process. 0ther important causes include infections (TB, %iral, fungal!, surgical remo%al, adrenal hemorrhage and metastasis. 1atients typically present #ith #eaness, fatigue, #eight loss, anorexia, depression, increased pigmentation and hypotension. 8yponatremia, hyperalemia, anemia and eosinophilia are seen. The 'est screening test is the cosyntropin (analogue of ACT8! stimulation test. An increase in serum cortisol le%els a'o%e "7 mcgd9 $7;7 mm after the administration of "67 mcg of cosyntropin %irtually rules out Addison=s disease. (Choices A and B! "3hr urinary free cortisol measurement and lo#dose dexamethasone suppression test are screening tests for Cushing=s syndrome. (Choice D! 2easurement of plasma ACT8 le%els is performed to distinguish 'et#een primary and secondary adrenocortical deficiency once the diagnosis of Addison=s disease has 'een made. 1lasma ACT8 le%els greater than 67 pgm9 indicate primary adrenocortical deficiency, #hereas le%els less than 67 pgm9 indicate secondary adrenocortical deficiency. (Choice E! 8ydrocortisone is used for the treatment of Addison=s disease. Itis usually started once the diagnosis has 'een confirmed using the a'o%ementioned 'iochemical tests5 ho#e%er, in %ery sic patients #ith a highly suggesti%e clinical presentation of adrenocortical insufficiency, treatment #ith a glucocorticoid may 'e started #ithout #aiting for the la'oratory results. Educational 0'*ecti%e: The 'est screening test for patients #ith suspected primary adrenal insufficiency is the cosyntropin (analogue of ACT8! stimulation test. An increase in serum cortisol le%els a'o%e "7 mcgd9 $7;7 mm after the administration of "67 mcg of cosyntropin %irtually rules out primary adrenocortical insufficiency (Addison=s disease!.
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Q NO 133: A 72-ye!-ol" #le co#e% o e e#e!e+cy "e,!#e+ (ED) "'e o %'""e+ o+%e o. !$-%$"e" 0ek+e%%/ ,%$ +" $+co+$+e+ce e "$" +o lo%e co+%c$o'%+e%% All $% %y#,o#% %!e" %'""e+ly/ 8 o'! o e 0% ,!e1$o'%ly "$+o%e" 0$ y,e!l$,$"e#$/ +" $% o+ %$#1%$+ e $% k+o0+ %#oke! +" lcool$c e $% k$+ %,$!$+ % ,!o,yl5$% .o! e! ck% +" %!oke% $% .#$ly $%o!y $% +o %$+$.$c+ $% &loo" ,!e%%'!e $% 8>9
IF nitroprusside to reduce 'lood pressure 4imodipine Tissue plasminogen acti%ator #ithin $ hours )treptoinase and heparin com'ination IF high dose corticosteroids
Explanation: )troe is the third most common cause of death in the +nited )tates. CT scan #ithout contrast should 'e performed in all patients #ho present #ith signs and symptoms of stroe. In the first "3hours the role of CT scan is essentially to rule out any hemorrhage in #hich case aspirin and t1A are contraindicated. In the a'o%e patient CT scan did not sho# any acute hemorrhage. If a patient presents #ithin $ hours after the onset of an ischemic stroe throm'olytic therapy #ith tissue plasminogen acti%ator (t1A! should 'e gi%en. 2any trials ha%e demonstrated impro%ed neurological outcomes #ith this approach in management. (Choice A! Although hypertension (8T4! is most common in the early acute period of stroe, aggressi%e 'lood pressure control is not ad%ised as this may impair the cere'ral autoregulation and #orsen the neurological outcome. Treatment is indicated #hen the systolic 'lood pressure is greater than ""7mm 8g or diastolic 'lood pressure is greater than $7mm 8g. 8T4 should 'e reduced o%er a period of se%eral hours. The preferred drugs are the calcium channel 'locers (e.g., nicardipine! and ACE inhi'itors. Intra%enous nitroglycerine and nitroprusside are not indicated. (Choice B! 4imodipine is used in the management of su'arachnoid hemorrhage ()A8!. It is a selecti%e cere'ro%ascular dilator and reduces the %asospasms that are induced 'y the )A8. (Choice D! The use of streptoinase in stroe patients has not sho#n any 'enefits. The drug actually increases the ris of 'leeding. The &DA currently recommends only t1A in the management of stroe patients. (Choice E! IF steroids are indicated for trauma (head in*ury! or tumor induced cere'ral edema (ele%ated IC1! Educational 0'*ecti%e: If a patient presents #ithin $ hours after the onset of an ischemic stroe, throm'olytic therapy #ith t1A (after CT scan! should 'e started. 2any trials ha%e demonstrated impro%ed neurological outcomes #ith this approach.
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 134: A 32-ye!-ol" 0o#+ co#e% o e E#e!e+cy De,!#e+ co#,l$+$+ o. %'""e+ o+%e o. %e1e!e %o!+e%% o. &!e &e+ .o'! o'!% o Se l%o % +o+,!o"'c$1e co' +" !$-%$"e" ce% ,$+ 0o!%e+% 0$ $+%,$!$o+ Se "e+$e% 1$+ .e1e!/ co'$+ ', &loo"/ 0ee6$+/ ,l,$$o+%/ le ,$+/ %0ell$+ o. e lo0e! e5!e#$$e% o! +y !ece+ !1el P% #e"$cl $%o!y !e1el% ,,e+"eco#y e 8; e! #e"$c$o+ $+cl'"e &$! co+!ol ,$ll% +" o1e!-e-co'+e! 1$#$+% e! .#$ly $%o!y $% :e!/ e >;/ % " "$&ee% .o! 29 ye!%@ #oe!/ e ;?/ % co!o+!y !e!y "$%e%e Se % +e1e! &ee+ ,!e++/ "!$+k% lcool %oc$lly +" "oe% +o %#oke e! 1$l %$+% !e T == P (3?C)/ BP 889<79 ##/ PR 839<#$+ +" PR 39<#$+ P'l%e o5$#e!y %o0e" ?; o+ > l$ o5ye+ Py%$cl e5#$+$o+ %o0% %l$ly o&e%e/ 0$e 0o#+ $+ c'e "$%!e%% Se $% le! +" coo,e!$1e 0$o' cy+o%$% o! '+"$ce Te !e% o. e ,y%$cl e5#$+$o+ $% +o!#l W $% e #o% ,,!o,!$e +e5 %e, $+ $% ,$e+% #+e#e+ A. B. C. D. E. &. G. 8.
E
Explanation: The most liely diagnosis in this patient is pulmonary em'olism. )udden onset of shortness of 'reath #ith clear lung sounds should al#ays raise the suspicion of pulmonary em'olus. 1ulmonary em'olism is a common, serious and potentially fatal complication of throm'us formation #ithin the %enous circulation. 1ulmonary em'olus is estimated to cause 67777 deaths each year in +nited )tates, maing it the third leading cause of death among hospitalied patients. 2any su'stances can em'olie to the pulmonary circulation including air, amniotic fluid, foreign 'odies (e.g., talc in IF drug users!, septic em'oli tumor cells and throm'us #hich is the most common one. is factors include: . Fenous stasis. ". 8ypercoagula'le states (cancer, protein C deficiency, protein ) deficiency antithrom'in Ill deficiency, malignancy, pregnancy, etc.!. $. 0'esity. 3. 1rior history of pulmonary em'olus. 6. 2alignancy. ;. 1regnancy. ?. Estrogen and tamoxifen. >. 1rolonged immo'iliation. @. Trauma of lo#er extremities. Tachycardia, fe%er, pleuritic chest pain, hemoptysis and nonproducti%e coughing are all consistent #ith pulmonary em'olus. This patient presents #ith dyspnea, tachycardia and nonproducti%e cough, #ith a 156
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
clear lung examination. 8er ris factors include o'esity and 'irth control pills. Differential diagnoses include: 1neumonia, 'ronchitis, pneumothorax, asthma, pleural effusion, and myocarditis associated #ith congesti%e heart failure. Thus the 'est initial step in this patient #ould 'e chest xray and ABG (Choice &!. Chest xray #ill help differentiate 'et#een these etiologies. Arterial 'lood gases most often sho# respiratory alalosis #ith hypoxia and hypocar'ia and ele%ated al%eolararterial (Aa! gradient. E
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 135: A 63yearold Caucasian #oman presents to your office #ith fatigue. )he also reports diiness and palpitations after moderate physical acti%ity. Additionally, her feet feel -num'/ and are less sensiti%e to cold than they used to 'e. )he has no significant past medical history. 1hysical examination re%eals pale con*uncti%ae and a shiny tongue. Anle reflex is decreased 'ilaterally. 9a'oratory findings include: 8emoglo'in .; mgd9 2CF 7 f9 2C8C $; gd9 BC count $,@77mmH 1latelet count 67,777mmH This patient should 'e monitored for #hich of the follo#ing longterm complications
A. B. C. D. E. &.
Acute myelogenous leuemia 8odgin=s disease Celiac sprue Gastric cancer 9i%er cirrhosis Tcell lymphoma
Explanation: This patient has classic signs and symptoms or %itamin B" deficiency. In particular, she has a macrocytic anemia, glossitis, and neurologic changes that include peripheral neuropathy. 1ernicious anemia, an autoimmune disorder #here the 'ody maes antiintrinsic factor anti'odies, is the leading cause of B" deficiency and the most liely etiology in this %ignette. 1ernicious anemia leads to %itamin B" deficiency in t#o #ays. &irst, antiintrinsic factor anti'odies decrease the amount of functional intrinsic factor a%aila'le to facilitate B" a'sorption. )econd, patients de%elop a chronic atrophic gastritis #ith decreased production of intrinsic factor 'y gastric parietal cells. This atrophic gastritis increases the ris of intestinaltype gastric cancer and gastric carcinoid tumors 'y "$ times o%er the general population. Thus, patients #ith pernicious anemia need to 'e monitored for the de%elopment of gastric cancer (periodic stool testing for the presence of 'lood!. There are no other cancers associated #ith pernicious anemia.
Educational 0'*ecti%e: 1ernicious anemia is the most common cause or %itamin B" deficiency and is associated #ith at least dou'le the ris of gastric cancer as compared to the general population.
158
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 136: A "?yearold Caucasian #oman presents #ith a'dominal pain, 'loody diarrhea and a 3.6 ("g! #eight loss for the past t#o months. )he descri'es the a'dominal pain as intermittent, moderatetose%ere, and located in the right lo#er Juadrant. 0%er the past 3> hours, the pain has intensified. )he denies any fe%er. 8er temperature is $?.; C (@@.; &! 'lood pressure is "7?7 mm 8g, pulse is 77min, and respirations are 3min. A'dominal examination sho#s tenderness in the right lo#er Juadrant #ithout re'ound. ectal examination sho#s mucus. ectosigmoidoscopy is unremara'le. An xray film of the a'domen sho#s gas in the small and large 'o#els. 9a'oratory studies sho#: 8' 7." gd9 BC ;,677cmm 1latelet count 6$7,777cmm E) 3>hr hich of the follo#ing is the most liely diagnosis
A. B. C. D. E.
Di%erticulitis Colon cancer Acute appendicitis Crohn=s disease Chronic ulcerati%e colitis
Explanation: The clinical picture is most consistent #ith an exacer'ation of a chronic inflammatory disease, particularly Crohn=s disease. Crohn=s disease can in%ol%e the GI tract an #here, from the esophagus to anus. It is freJuently associated #ith intestinal fistula, strictures and anal disease. 9a'oratory findings of e%ery chronic inflammatory disease can include anemia and reacti%e throm'ocytosis. (Choice B! Colon cancer rarely causes pain, unless it is %ery ad%anced. It is also unliely to occur in a young patient. (Choice C! Acute appendicitis is an unliely diagnosis since the duration of this patient=s symptoms is too long (i.e., " months!. &urthermore, she does not ha%e any characteristic signs of appendicitis, such as re'ound tenderness and guarding. (Choice A! Di%erticulitis is associated #ith constipation (rather than diarrhea!, and usually produces left lo#er Juadrant pain. It is usually seen in elderly patients. (Choice E! +lcerati%e colitis can also present as 'loody diarrhea: ho#e%er, it nearly al#ays in%ol%es the rectal mucosa.
Educational 0'*ecti%e: Al#ays suspect Crohn=s disease in a young patient #ith chronic 'loody diarrhea.
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USMLE WORLD STEP 2 CK 3*
(INTERNAL MEDICINE) *Block
Q NO 137: A 4;-ye!-ol" #le ,!e%e+% o yo'! o..$ce &ec'%e $% G+"% !e e$+ $ck +" %0olle+H e $% l%o 1$+ "$..$c'ly 0$ 0e!$+ %oe% &ec'%e $% .ee 1e &eco#e l!e $% &loo" ,!e%%'!e $% 8;9<=9 ## O+ e5#$+$o+/ e % e+l!e"/ %0olle+ +"% +" .ee e % co!%e .c$l .e'!e%/ 0$ ,!o#$+e+ .!o+l &o+e% +" 0% W$le yo' !e "$%c'%%$+ e #o% l$kely "$+o%$%/ e ,,e!% 0o!!$e" +" %k% &o' e co#,l$c$o+% +" !$%k o. "e %%oc$e" 0$ $% co+"$$o+ W $% e #o% co##o+ c'%e o. "e $+ ,$e+% 0$ $% co+"$$o+ A. B. C. D. E.
Congesti%e cardiac failure 8ypertensi%e nephropathy )troe Brain tumor Adrenal failure
Explanation: Acromegaly is a clinical syndrome that is characteried 'y gro#th hormone (G8! excess from somatotroph (pituitary! adenomas. Its clinical features result from the high G8 concentration, #hich also causes excessi%e production of insulinlie gro#th factor I (IG&I!. IG& excess leads to the excessi%e gro#th of 'one and soft tissues. Direct and indirect effects (%ia IG&! of G8 excess also contri'ute to cardio%ascular manifestations. 1atients ha%e an increased incidence of coronary heart disease, cardiomyopathy, arrhythmias, left %entricular hypertrophy, and diastolic dysfunction. The o%erall leading cause of death in patients #ith acromegaly is cardio%ascular, accounting for $> ;" of deaths. espiratory causes account for 7"6, and malignancy accounts for @"6 of deaths. 8ypertension occurs in approximately $7 of patients5 ho#e%er, hypertension itself is not solely responsi'le for the increase in cardio%ascular mortality. 4ormaliation of hormone le%els follo#ing successful treatment of acromegaly maredly reduces cardio%ascular mortality. (Choices B, C, D and E! 1atients #ith acromegaly can succum' due to noncardiac reasons5 ho#e%er, these occur less commonly than cardio%ascular causes. The follo#ing are some noncardiac causes of death in patients #ith acromegaly: i. )troes: the incidence of stroes is higher in patients #ith acromegaly ". Colon cancer this condition is thought to occur #ith increased freJuency $. enal failure: this can result from hypertension and hyperglycemia 3. Adrenal failure: this can occur due to hypothalamopituitary pro'lems due to a pituitary tumor, although surgical resection and radiotherapy of the pituitary tumor can also cause secondary adrenal failure
Educational 0'*ecti%e: The most common cause of death in patients #ith acromegaly is cardio%ascular, accounting for approximately $>;" of deaths.
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