NBME 12 explanations Good luck to all my mates on feedurbrain. Special thanks to Joe to Joe for for the initiative & all the members who participated in 13, 5 & 6 explanations.
BLOCK 1 1. Patient is unsure about receiving a transplant & if he were to undergo the procedure, he would rather get a donor kidney from one of his relatives than from a cadaver. Now option A is not appropriate as transplant confers the greatest survival advantage. Option D is also wrong as living donor transplant gives superior result (provided such an option is available). E is also wrong as first doctor needs to discuss why the patient is unsure about getting transplant before jumping onto assessing his suitability for the procedure. Option B & C are right but B is better as it is important to know what are his concerns regarding transplantation that are making him unsure, also clear him on donor vs. cadaver issue as although living donor is better but so is the time interval between initiation of dialysis & transplant if he is unable to get on e from relatives. 2. Chlordiazepoxide, a BZD, depresses CNS in very high doses leading to ↓Po2 ↑Pco2 ↓pH. 3. Option E is the odd one out, rest all merely states the fact that most smokers already know yet r unable to quit as the habit & addiction r overpowering. It would be helpful to know at what level is patient trying, helping/encouraging him accordingly rather than merely imposing on him that he needs to quit or putting it out bluntly like how can I help you. 4. Loose & transient attachment by neutrophils + molecule present on endothelial cell surface = Selectins. 5. Ehrlichiosis ↔ treatment doxycycline ↔ inhibits protein synthesis. 6. Diastolic murmur heard in specific position due to obstruction caused by tumor + echo shows pedunculated mass attached to left atrium - most common primary tumor of the heart in adults – myxoma. 7. Postganglionic lesions are usually not associated with anhidrosis because t he sympathetics for their innervation diverge from the sympathetic pathway before the superior cervical ganglion. 8. See pic below. 9. Diarrhea & serum gastrin concentration → Zollinger -Ellison Syndrome suspect → Proton pump inhibitors. 10. Spherocytes seen - small, dark-staining red cells lacking the central zone of pallor – either due to hereditary spherocytosis or autoimmune hemolytic anemia (not given in the options).
11. Vinblastine – blockage of microtubule assembly. 12. Myocytes - Glut 4 – graph B → basal transport occuring independently of insulin, with rate increasing when insulin levels rise. 13. Avoids eye contact, unable to interact socially with his peers, intelligence & language development normal, fascinated & excessively occupied with it = Asperger. 14. NNT = 1/attributable risk; attributable risk = 2.3% – 1.3% = .01 15. Herpes – vesiculoulcerative lesion on vermilion border of the lips. Latent state maintained in neurons. 16. Low Hb affects arterial O2 carrying capacity, not arterial Po2 as it is due to the O2 gas dissolved in blood not O2 attached to Hb. 17. Secondary immune response – option A. 18. Smoker, living in basement + winter season (poor ventilation), symptoms suggestive mild CO poisoning → Option D. 19. 95% decrease in parietal cell → very less intrinsic factor = pernicious anemia. 20.
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I uptake low → thyroid is not being stimulated. Serum thyroglobulin is low, so can’t be a case of hyperthyroidism due to destruction of thyroid follicles. Also there is no enlargement of thyroid, no exophthalmos. Option A correct.
21. Small testes, tall → most probably klinefelter’s ↔ Common cause of hypogonadism seen in infertility workup. 22. Extreme stress → hypothalamic-pituitary failure. 23. Tiotropium – Anticholinergic. 24. Pheochromocytoma ↔ Neural crest cells. 25. Prostate cancer – One of the treatment modality being pharmacological orchiectomy by using long acting GnRH agonists. They act by causing desensitization & down regulation of GnRH receptors. 26. Cytotoxic T lymphocytes (MHC-1) recognize virus-infected. Fas ligand present on these lymphocytes plays role in inducing apoptosis in such cells. It is one of the many ways by which cytotoxic T cells get rid of such cells. st
27. 1 step look at pH to know whether acidosis or alkalosis as compensatory nd mechanism can only reduce it, never fully rectify it. 2 look at HCO3 & Pco2 the one which is in accordance with pH will be the primary abnormality like in this case HCO3 is decreased hence responsible for the decreased pH so metabolic acidosis. And one opposite to the current pH will be compensatory, in our case respiratory ↔ pCO2. But the Q is asking for renal compensation which is: an adaptive increase in NH3 synthesis, aiding in the excretion of excess H+. 28. Most likely to be a case of diverculitis: 48yr old (occurs earlier in western world due to less dietary fibre), fever, colicky lower abdo minal pain, tenderness over left quadrant, normocytic anemia probably to blood loss & leukocytosis. Treated with antibiotics. Recommendation: include fibre in diet. 29. K m cannot be predicted based solely on the value of velocity as it also depends on concentration of substrate & concentration of enzyme. 30. Vertebral border of scapula protrudes ↔ serratus anterior paralyzed ↔ long thoracic n. 31. Diplococci present inside PMNs = Neisseria = Ceftriaxone. 32. BCL-2 increased → ant-apoptotic. 33. External Validity is of greater importance than accurac y. External Validity implies results of a particular study can be generaliz ed i.e. holds true in most types of circumstances, not only under which test was done whereas accuracy means how closer is the result of our test to the original under the circumstances of the study. Face validity means how good test looks to achieve what it intends to. Precision means to what level u can measure the result for example how many decimal points. Reliability = does tests gives the same result/close when conducted again & again.
34. Infliximab → binds & neutralizes TNFα. 35. 18 month old boy, sudden onset dyspnea alongwith decreased air movement & wheezes = Foreign body aspiration. 36. PCP should be considered in any immune-compromised patient who develops respiratory symptomatology, fever, and an abnormal chest radio graph, classically showing bilateral diffuse infiltrates. Histologic finding = eosinophilic alveolar exudate. Host inflammatory response mainly consists of scanty macrophages. CD4 T cells play central role in our defense against it hence impaired cellular immunity main predisposing factor. 37. Sympathetic → Arterial constriction, Heart rate ↑, venous constriction. 38. Further evaluation: most likely to be a case o f autism: “sits on table lookin at reflex hammer, indifferent to his mother’s presence”. Option C is wrong a s not all patients with autism are mentally retarded: needs further testing. 39. Neisseria ↔ capsular polysaccharide. 40. Angiotensinogen, synthesized by liver. Much of the conversion of Angiotensin I to II by ACE occurs as the blood passes through the lungs. 41. Ribavarin, a purine nucleoside analogue, combined with INFα is the standard treatment for Hepatitis C. 42. Subluxation of radial head: 1) one of the most common elbow injuries in children, typically occurring between ages 1 and 4 years, the radial head being smaller than the diameter of the annular ligament more easily slips out from it. 2) The usual cause of injury is sudden longitudinal traction on the arm with the elbow extended, like pulling the child by wrist. 3) The arm is usually held in pronation. 43. Portal hypertension – only 1 of its tributaries given → short gastric veins. 44. ↓ Preload + ↑ coronary blood flow = Nitrates by ↑cGMP. Calcium chann el blockers markedly relax arterioles but have mild effects on veins so not much lowering of preload. 45. Moderate difficulty learning & recalling new material → Hippocampus. 46. Thymidine dimers ↔ UV ↔ Xeroderma Pigmentosum ↔ Exinuclease def. 47. V2 receptor deficiency as no change after administration of desmopressin. 48. See pic below.
49. 45 yr old female, C/O menometrorrhagia, nodular enlarged uterus & no mitoses present – Leiomyoma (most common benign uterine tumor). Shrinkage occurs after menopause. 50. Corticosteroids ↔ nuclear receptors.
BLOCK 2 51. Acute Tubular Necrosis (necrosis of many of the renal tubular cells due to shock). No damage to the underlying stromal framework so E. 52. E-cadherin is responsible for keeping the epithelial cells adhered to each other. 53. Bromocriptine, dopamine agonist, decreases prolactin release. 54. 1 month H/O excessive urination, weight loss, blood glucose concentration: 612 + fruity odor = DKA → Kussmaul respiration → ↓ Arterial Pco2. Rest all ↑. 55. Montelukast: Blockade of the leukotriene receptor. 56. No. of lines(cases) touching Dec 31 = 4. 57. O ptions given E is most appropriate → ↓ glucuronidation. A & F not as direct bilirubin below 2 and also not D as Coombs (DAT) is negative. 58. LEPTIN – decreases food intake & increases energy expenditure. Cholecystokinin, Glucagon like peptide also decrease food intake but r responsible for short term meal-to-meal control of food intake while effects of LEPTIN r prolonged. Ghrelin & Neuropeptide Y r responsible for increase in food intake. 59. More pronounced murmur during inspiration → Right sided. Systolic murmur in a pregnant female, 30 weeks gestation, is due increased output thru aortic & pulmonary valve. However Q states lower left sternal border but pulmonic
nd
ejection murmur is best heard in the 2 left ICS not lower sternal border (area for maximal murmur intensity of tricuspid valve). 60. Abdominal pain & distension + air fluid levels in the upright abdominal X-ray = Obstruction. Upper GI series shows small bowel in the right side of the abdomen: Nonrotation, only thing being very unusual is 24 yr old presenting with it, st normally malrotation manifests in 1 month of life 90% of the time. 61. Clinical phenotype: Hyperparathyroidism = gain of function. 62. 65 yr old man waking with shortness of breath after 3-4 hours of sleep + gradual improvement after getting out of bed = paroxysmal nocturnal dyspnea. Auscultation of lung shows inspiratory crackles at the bases bilaterally = pulmonary edema: Heart failure. Also vitals r in accordance with diagnosis. 63. Only NE increases the peripheral vascular resistance among the drugs given. 64. State the finding (to clear - why r u asking) & start with open ended Q (not too specific), easier for patient to start conversing esp in sensitive situations. 65. Pioglitazone – improves insulin sensitivity by acting on PPARγ. 66. Hypospadias – failure of urethral folds to fuse completely. 67. Painless, hard mass + raised α-fetoprotein = Nonseminomatous tumor. 68. Low glucocerebrosidase activity: Gauchers Ds ↔ lysosomal storage disorder. 69. HMG-CoA Reductase inhibitor = rarely liver damage & m yopathy can occur. 70. Renal Agnesis → Oligohydramnios. 71. 6 yr boy with cough, rapid breathing & wheeze (heard throughout the lung fields) = Asthma. Tactile fremitus is decreased due to widespread narrowing of tracheo bronchial tree. 72. Maximum in early diastole. 73. Post menopausal female, smoker for past 25 yrs Blood pressure 150/80 S4 gallop Point of maximal impulse laterally displaced ECG shows left axis deviation
= Hypertensive Heart Disease
AV nicking & Copper wiring → 3 grade hypertensive retinopathy. rd
74. 70 yr old man, smoking for past 25 yr present with: i)flank pain, ii)mass, iii)hematuria → Renal cell carcinoma. Commonly arises from the pole as the MRI shows & has metastasized. 75. 58 yr man smoking for past 35 yrs!! with long history of cough, has lost 8kg in 1yr + CXR shows apical mass: Lung cancer involving phrenic nerve leading to elevation of diaphragm. 76. Aripiprazole is partial agonist at D2 receptors. 77. Isolates from various geographical locations r similar + differ from those recovered in previous years + increased mortality = Antigenic shift = ressortment of genes encoding hemagglutinin. 78. Sudden death in a young male (along with family history of same), at autopsy septum is found to be asymmetrically thickened → HOCM. st
79. Mother immigrated from mexico, no previous immunizations, suffers from 1 trimester “illness” → rash, adenopathy + child was born premature with low birth weight along with jaundice, purpura & cataracts = Rubella 80. Drug mentioned = protease inhibitor ↔ Indinavir. 81. Cutaneous larva migrans ↔ characteristic red itchy tracks (no accompan ying systemic complaint) - caused by dog or cat hookworms larva burrowing through the skin, usually self-limited as little further development of parasite occurs. Plus the history of returning from lake prior to developing this lesion helps, also children r the ones commonly affected. Drug used mebendazole. 82. 75 yr man + moderately & symmetrically enlarged prostate gland without nodules + markedly distend bladder with severely raised BUN & creatinine causing stupor/confusion = BPH. 83. Pic shows budding going on. 84. All other options will have their effect after quite some time (prevention) except external automatic defibrillators (treatment). 85. Control includes people without the risk factor under study, in this case: colonic polyposis. 86. Hydroxyurea increase HbF levels which has inhibitory e ffect on HbS polymerization. 87. Hemolytic disease of newborn; Fc receptors b y binding to the maternal IgGs can mediate the transplacental transfer.
88. Young female with focal neurologic sign + 1 month back had an episode of what seems to be optic neuritis (dissemination in time) + MRI shows 2 white matter hyperintensities (dissemination in space) = MS = autoimmune response to myelin. 89. Muscle fibers - type 1(red) & type 2(white). When these fiber types r stained differentially a checkerboard pattern is seen. Nerve supp ly - individual motor units r homogenous for muscle fiber type as fiber type is regulated, in part, by innervation which leads to transcriptional activation of fiber type specific genes. In chronic neuropathy remaining healthy axons sprout & synapse with denervated fibers. As a result motor units enlarge and their fiber, instead of b eing scattered, comes to lie adjacent to one another.
90. Fracture neck of fibula common fibular n. involved → foot drop, no effect on plantar flexion & Achilles reflex. th
91. Cranial N (8 ) & Cerebellar Peduncle (Inferior) lesion ↔ affect ipsilaterally. 92. Contact dermatitis = type IV delayed T cell mediated hypersensitivity (nonimmunologic if due to irritant). 93. The hydroxyl groups (-OH) of serine, threonine, tyrosine or histidine amino acid side chains are the most common target for phosp horylation. Serine and threonine are sites for O-linked glycosylation of proteins in Golgi. 94. Median will decrease [1→ (1+.9)/2], mode same, decrease in mean too. 95. CLINDAMYCIN + diarrhea with fever, leukocytosis, also abdominal examination shows distension & tenderness = Clostridium difficile. The most widely used method of diagnosing C. difficile associated diarrhea & colitis is detection of C. difficile toxins in stool. 96. Variable expression… see FA, explained with examp le of NF. 97. Bleeding gums, ecchymoses & perifollicular hemorrhages = Vit. C def. 98. Worsening acne over forehead required to wear helmet during work. 99. Ophthalmia neonatorum. Blue stained (Giemsa) intracytoplasmic inclusion bodies. Culture grows no pathogen. – Chlamydia (most common cause of O.N.). 100. Multiple myeloma. Bones scan primarily detects osteoblastic activity that's why no abnormalities.
BLOCK 3 1. Motile ovoid organisms: Trichomonads. Patchy macular erythematous lesion o n the cervix: Strawberry Cervix seen in trichomoniasis. Vaginal pH elevated. Only thing bit off the mark is thick yellow discharge (frankly purulent) [which may be due to secondary bacterial infection], in trichomonas infection greenish frothy discharge is seen. 2. Alcoholic, 2 month history of epigastric pain, foul smelling stools + weight loss + ↑ fasting serum glucose + pancreatic calcification: chronic panc reatitis. Steatorrhea + Inc fasting Glucose due to exocrine (↓ elastase in stool) & endocrine pancreatic insufficiency Alcohol ↑ the protein content of pancreatic secretions resulting in formation of protein plugs (which may calcify) → Obstruction → Pancreatitis. 3. Warfarin inhibits carboxylation of coagulation factors. 4. Cell mediated immunity responds against Chlamydia. 5. Undifferentiated stem cells. 6. Women of reproductive age group with t ypical butterfly rash & pericarditis, migratory non-erosive arthritis/arthralgia i.e not causing joint deformities → SLE. Anti-ds DNA = most specific. 7. Home-canned green beans + blurred vision, dry mouth, dysarthria, descending paralysis = Botulinum ↔ Mechanism: ↓ release of Ach from Presynaptic neuron. 8. Fainted while waiting in line + immediately after this occu rred pulse rate was noted to be low + now totally normal with no abnormalities on PE = ↑ vagal tone. 9. Case of reye’s syndrome ↔ mitochondrial dysfunction. 10. SSRIs 11. Patients have right to choose their treatment optio n, needs to be respected by physician. Other clues: woman is retired teacher, after discussing options thoroughly she returns 1 week later with her decision, no mood disorder. 12. Stimulation of auditor nerve. 13. 5-HT3 receptor antagonist. 14. IL- 10 ↔ Anti-inflammatory.
15. Endometrial hyperplasia ← Estrogen. As she is post-menopausal cant be pituitary tumor. 16. Sensitivity = True positive/total people with disease = 200/250. 17. Splitting, intense unstable relationship, self detrimental impulsivity & cant bear being alone - Borderline. 18. 2-month history of difficulty attaining an erection, normal libido → Sildenafil ( ↑ cGMP in smooth muscle). 19. ACE inhibitor will further dec. BP (since the diuresis will stimulate the reninangiotensin system) & restore potassium. 20. According to simplified Hardy-Weinberg equation: Disease prevalence of 2 cystinosis = (allele frequency) so allele frequency = 1/200 & carrier frequency = 2q = 1/100. 21. ↑Phosphoenolpyruvate Carboxykinase, ↑ Glucose 6- phosphatase due to ↑ Gluconeogenesis & ↓ Pyruvate kinase, ↓ Fructose 2, 6-bisphosphate to reduce glycolysis of glucose being produced by liver by gluconeogenesis. 22. Depressive, most critical to ask for suicidal ideation. 23. Varicose veins ← defect in venous valves. 24. Right thing will be to tell her this is sometimes problem as p eople grow older so as to make her feel less embarrassed and try to be polite & begin with open ended Qs so that it is easier for her to start then graduall y go for specific Qs. 25. The main DDs for focal CNS lesion in AIDS patient is i) Toxoplasma ii) Lymphoma. The probability of lymphoma ↑ & that of toxoplasma ↓ in presence of single lesion in MRI (not CT) as in majority (70-80%) of tox oplasmosis cases multiple lesions r seen therefore brain biopsy was required in this case to obtain definitive diagnosis which in this case showed cresent shaped organisms (tachyzoites), they r actually hard to see especially in CNS as there is predilection for formation of tissue cyst which r spherical in shape. 26. Stupor, respiratory depression (respiratory rate 8, ↓ lung vol, distant lung sounds & ABG analysis pH ↓, PCO2 ↑, PO2 ↓) → Opioid overdose. Pinpoint pupil would have completed the characteristic triad. 27. Unable to flex the elbow & supinate the forearm against resistance → Biceps, Brachialis muscle → Musculocutaneous N. 28. 55 yr old male, 2 yr history of intermittent pain in his right great toe → Urate. Calcium pyrophosphate crystal deposition does not involve this joint, most common joint being involved is knee.
29. Oxycodone (opiate derivative) → GCS will be depressed along with respiratory depression & pupils being constricted. 30. Coding strand sequence is given. Two types of mutations occur i)β0 (no synthesis of β globin synthesis ii)β+ reduced synthesis of β globin. Of these β0 r most likely to manifest. Now mutations can occur at three sites i)Splicing site, either leading to destruction of normal splice site(β0) or addition of an ectopic splice site (β+), ii)Promoter region with red. synthesis (β+), iii)chain terminator mutation in exon 0 causing β type.(Robbins) Now in the Q we need to look for mutation occurring at splicing site or exons (as only these can cause β0 mutation which r more likely to manifest). Option 3 mutation is far away from splicing site so is no-no, Option 2 is occurring at splicing site so can be, Option 1 is occurring in exon but as we can see it cannot cause chain termination so not ans. So the answer is 2. 31. Petechiae & easy bruising ↔ low platelet count, low Hb, Hematocrit, low normal leukocyte count, Inc Reticulocyte count due to Hypersplenism associated with portal hypertension. Inc PT due to cirrhosis. 32. Howell-Jolly bodies (nuclear remnant) seen in asplenia. 33. Noncontrast CT scan shows hemorrhagic stroke (hyperdensity). Most imp risk factor being Hypertension. 34. Myasthenia gravis, decreased available Ach recep tor on postsynaptic plasma membrane. nd
35. Not papilloma or polyp as outgrowth is not seen in 2 slide. Hoarse voice persisting for 1 month with risk factor smoking present + lesion seen on true nd vocal cord (most common site for carcinoma dev elopment) + 2 slide showing invasion of squamous cells → squamous cell carcinoma. +
36. Normally maximum amount of filtered Na is reabsorbed in the proximal tubule so the greatest decrease will be in this segment. 37. Inc hydrostatic pressure in pulmonary venous circulation due to ischemic myocardial dysfunction. 38. Symmetric enlargement of thyroid gland for 5 mo nths, gets tired easily + serum thyroxine levels low → Hashimoto’s thyroiditis: presence of anti thyroid peroxidase antibodies. 39. Characteristics of ulcer don’t help, but small gram negative ba cillus (coccobacillary) & chocolate agar suggest Haemophilus ducreyi. 40. Irreversible → aspirin.
41. Child below the age of 1, not immunized, paroxysm of coughing with inspiratory whoop at the end (not forced expiratory grunt as the Q states), leukoc ytosis with lymphocytosis ↔ Pertusis → toxin secreted increases the activity of adenyl cyclase which inhibit migration & activation of neutrophil. rd
th
42. Thymic aplasia results from dysmorphogenesis of 3 & 4 pharyngeal pouches leading to hypoplasia or aplasia of parathyroid gland also. Other co-occurring abnormalities include hypertelorism, low-set notched ears, shortened philtrum, & cleft palate. (DiGeorge Syndrome). It is frequently the othe r way round diagnosis is often first suggested by hypocalcemic seizures during the n eonatal period & it is critical to obtain T cell count on all infants born with primary hypoparathyroidism as the disease is fatal without treatment. 43. The murmur is due to ischemic papillary muscle dysfunction resulting in Mitral regurgitation (holosystolic murmur heard over the cardiac apex). 44. Chronic Rejection: Intimal thickening (responsible for loss of tubules, interstitial fibrosis & glomerular damage from chronic ischemia), the vascular intima gets replaced by accumulation of smooth muscle cells & fibrous connective tissue; elastic laminae may form in the muscular compon ent as seen in the slide. 45. Release of dopamine in the nucleus accumbens is responsible for reward phenomenon & hence reinforcement, 46. Closure of rostral end of the neural tube. 47. Speech not spontaneous, brief phrases without intonation – Broca’s Aphasia. Associated features can include dysarthria, right hemiparesis affecting face, arm more than the leg especially when left MCA superior division is the cause of infarct. 48. Renal arteriolar perfusion will be decreased. 49. ESRD → ↑ Phosphate, ↓Ca++ → ↑ Parathyroid hormone. 50. Glycosylation: inside the mitochondria.
BLOCK 4 1. Weird Question… as monoclonal antibodies to IgE will either prevent b asophil degranulation, or not (if those IgE antibodies r alread y bound to basophil), as both the IgE receptor present on basophil & monoclonal anti-IgE antibodies bind to Fc region of IgE . 2. Weight loss + hemoglobin A1c high = Decreased self administration of insulin; all others (laxative, decreased intake, vomiting & intense aerobic exercise program) would have not raised Hb A1c. 3. Excessive muscle mass, thick beard, profuse male pattern body hair, serum testosterone raised & testicles r atrophic: testosterone administration (causing atrophy of testis through hypothalamic-pituitary axis suppression hence undetectable LH). 4. Symptoms of mucosal bleeding & except for low platelet count all other things r normal (No need for Bone marrow aspirate in suc h situation!!! which by the way shows increased megakaryocytes): ITP. 5. Endocarditis following Dental procedure = Srep viridans. 6. Calcitonin is tumor marker for medullary thyroid carcinoma. 7. Severe abdominal pain, shoulder pain (due to irritation of diaphragm) signs of peritonitis & air under right dome of diaphragm: perforated viscus. 8. B cell markers CD19, CD22 present. Pre-B as only cytopasmic Igµ is positive but cytoplasmic Igκ & surface Ig r negative. 9. Ileum is least likely to be directly inspected b y surgeon during lap cholecystectomy. 10. Aspirin & clpoidogril r the only option available fo r the purpose; NSAIDs other than aspirin are reversible inhibitors, producing short lasting inhibition of platelet function, not useful clinically. 11. Photograph → strawberry tongue; occurs with scarlet fever & Kawasaki disease. Vasculitis of medium sized arteries with predilection for coronary arteries. Classic clinical criteria/epidemiological case definition: i) Fever persisting atleast for 5 days, ii) polymorphous exanthema, iii) conjunctival injection (without ex udates), iv)erythema & edema of hand & feet followed by peeling of finger, toe in 2-3 weeks, v) injection of oral mucosa & strawberry tongue, vi) cervical lymphadenopathy, usually unilateral.
12. Diagnosis: REM behviour disorder (absent muscle atonia during REM sleep ) as the description of acting out a dream is quite typical & it usually affects older men. 13. Grey white patches that bleed on scraping: pesudomembrane (C. diphtheria); the bacteria in order to cause disease must be lysogenized by a temperate bacteriophage (which codes for exotoxin); There r some weird things mentioned in this question i) one should never try to scrap off the pseudomembrane as systemic absorption of tox in will be enhanced, ii) this guys who has been living in hiati for all his life and when after immigrating to US he goes to trip home he contracts the disease iii)in most developing countries either children r usually immunized against it or secondly if not immunized catch the disease early in childhood or early adolescence, not this late. 14. After dissolution of such massive PE, obviously strain on right ventricle will be relieved. 15. Azoles inhibit 14-α-demethylase which converts lanosterol to ergosterol, thus it will be the most likely target of mutation in our Q. Although resistance most commonly occurs via decreased intracellular accumulation of azoles. (Kaplan) 16. Enterococcus faecalis; Risk factor for Stap aureus inf. being bacteremia (hematogenous route of infection). -
17. Acetazolamide works by increasing excretion of HCO 3 hence compensating for hyperventilation induced metabolic alkalosis at high altitude. 18. PDA - Harsh systolic murmur at left upper systolic border, 3hr later diastolic component appears as pulmonary vasculature dec reases, finally murmur disappears few hrs later as smooth muscle in the wall of ductus contracts, also that’s why ultrasonography discloses no cardiac abnormalities. 19. H/O amenorrhea + serum LH & FSH increased = (Premature) Ovarian failure. 20. Urease generates ammonia from endogenous urea & thereby elevates local gastric pH. 21. Fastest measurable physiologic response will be generated by ligand couple ion channels; example - Ach mediated depolarization. 22. RCT is an intervention trial… As for others, in case series - no control & in ecological/cross-sectional study - temporal sequence of event cannot b e determined. Case-control is the most appropriate study design.
23. Gestational trophoblastic neoplasia (H. mole) is an abnormal proliferation of placental tissue i.e trophoblasts. 24. Baclofen acts at GABAb receptors. About last option Tizanidine (a centrally acting muscle relaxant) is α2 agonist inhibiting excitatory interneurons. 25. Bilateral gluteal muscle weakness , (also inability to keep up with his peers on playground) suggests muscle dystrophy. (Frequent) falls is another feature (fall from porch in this case was responsible for fibular fracture). About pain, not given as a symptom of muscular dystrophies in Nelson!!! but can be found on googling. And there is history of 6 months so the timing of onset of symptom is quite in agreement to that of Duchene muscular dystrophy. 26. Arthr itis so ↑ Neutrophils ↑ Inflammatory mediators (Interleukin-1 & TNF) ↓Complement (due to activation & fixation). 27. Blocks depolymerization of microtubules (M phase specific). 28. Botulinum toxin inhibits the release of Ach. 29. She seems to be a case of pancreatic carcinoma; age (median age for diagnosis for being 65), 4 month history weight loss, obstructive jaundice (due to distal bile duct obstruction), mass at the head of pancreas & mild epigastric pain. Now in such case it needs to be seen whether tumor is respectable or not (mostly this being the case) & if it is not then there is need to relieve the jaundice by CBD stenting through endoscope. If not a candidate for endscope then we go for percutaneous stenting. Also in minority of cases where the carcinoma is resectable it is not preferable to go for preoperative stenting as it increases the complication after operation.
30. Hepatomegaly (massive), symptomatic hypoglycemia 3-4 hrs after eating, glucagon fails to have any effect on blood glucose : Von Gierke’s Disease. If the manifestations (hepatomegaly & fasting hypoglycemia) were mild then cou ld have been Hers (type VI). Also other findings pointing towards Von Gierke’s r doll like face & other biochemical hallmarks of the disease given (lactic acidosis, hyperlipidemia). th
31. Dandy-Walker malformation = cystic expansion of 4 ventricle & midline cerebellar hypoplasia = metencephelon development was affected prenatally. +
32. Depolarizing agents (Succinylcholine) can release K rapidly from intracellular sites. Also patients with hemiplegia or quadriplegia show abnormal responses (severe hyperkalemia) to depolarizing agents (probably because of receptor proliferation).
33. Multiple abscesses in hair follicles on arm of 3 year old child + gram positive cocci = Stap: site of carriage = Nares. 34. No carbonic anhydrase in RBC → no HCO-3 → no chloride shift. 35. Area for insertion: 4-5 intercostal space in the anterior axillary line at the level of the nipple. This corresponds to the anterior border of latissimus dorsi, lateral border of pectoralis major, apex axilla, and line at the level of the nipple, often referred to as the “triangle of safety.” Anterior serratus muscle present here. 36. Recombination. 37. Vd = amt. of drug ingested / plasma conc. → this shows that the drug being lipophillic is getting deposited into the extra adipose tissue present. 38. HYDROPHOBIA, hypersalivation , SCAR (numb) present on right upper extremity. Child is confused, agitated & developed fever, headache 5 days prior to admission --- Rabies. 39. Left eye deviated towards midline = lateral rectus paralyzed = abducent N. 40. As result of each test in three battery test is independent, laws dictate us to combine probabilities by multiplication. .95×.95×.95×100 = 85. 41. Tumor cells either secrete proteolytic enzymes or induce cells (such as fibroblasts or inflammatory cells) to elaborate proteases like MMP to degrade the interstitial connective tissue for invasion. 42. TNF-α inhibitors predispose to reactivation of TB, all symptomatology also point towards it: 4 week H/O fever, night sweats, fatigue, weight loss, CXR left upper lobe cavity. 43. Mousy odor; also eczema r the main distinguishing point here plus the fact that the child did not receive any kind of medical check-up before this visit also kinda suggests. All the others signs: Vomiting, Developmental delay & self mutilation (self mutilation being common to all intellectually disabled syndrome) common to large number of inborn error of metabolism. 44. Findings typical of hemizygous muscular dystrophy in a female suggests normal chromosome inactivated by lyonization. 45. Grief response → supportive counseling. 46. Abnormal nitroblue tetrazolium test → NADPH oxidase def. 47. Staghorn calculus, Proteus, alkaline urine → Struvite stone (Ammonium Magnesium Phosphate).
st
48. 1 line captures the diagnosis: green vomit (bile stained): obstruction of small bowel, also abdominal distension, painful/tender. 49. Alcoholic, 3 day history of ophthalmoplegia, confusion. She is disoriented & recall is poor → Wernicke encephalopathy (Vitamin B1). 50. Normal histology: minimal change disease (most common cause of proteinuria in children).
