USMLE STEP 2 CK REVIEW ~ HEMATOLOGY TRANSFUSIONS
Blood Groups o Blood Abs Produced in peyer’s patches – M-cells transport A & B antigens to nearby B-lymphocytes B-cells produce natural antibodies against antigens not present on RBC surface o Type A A antigen on RBC surface & B antibody in plasma o Type B B antigen on RBC surface & A antibody in plasma o Type AB Both A & B antigens on RBC surface w/no antibodies in plasma – universal recipient o Type O Neither A nor B antigen on RBC surface w/both antibodies in plasma – universal donor o Rh Type Rh mothers exposed to Rh blood produce anti-Rh IgG – MC during child birth In subsequent pregnancies anti-Rh IgG can cross placenta & cause HDN Prevent by giving mother Rh antigen Ig after delivery of first Rh baby
Transfusion Types o PRBCs No platelets or clotting factors – each unit Hb by 1 g/dL & Hct by 4% Mix w/NS to infuse faster – don’t mix w/lactated ringer's since Ca2+ causes coagulation in IV line Transfuse within 35 days to avoid hyperkalemia from cell lysis o Platelet Transfusion Contraindicated in TTP/HUS, HIT, HELLP, ITP Suspect following if PC not seen post-transfusion – alloantibodies, sepsis, hypersplenism o Fresh Frozen Plasma (FFP) Contains all clotting factors – but no RBCs, WBCs or platelets Indications include sepsis, DIC, dilution, TTP/HUS, liver failure o Cryoprecipitate Contains fibrinogen, vWF, factor VIII & XIII Indications include vWD, Hemophilia, hypofibrinogenemia, DIC o Whole Blood Only for massive blood loss – rarely used
Hemolytic Transfusion Reactions o Acute Hemolytic Transfusion Reactions (AHTR): ABO incompatibility causing intravascular hemolysis 2O to complement activation Occurs immediately after transfusion – MCC is clerical error Symptoms Fever, chills, N/V, flank/back pain, chest pain, dyspnea Complications ARF w/hemoglobinuria, hypovolemic shock or DIC Treatment Stop transfusion & aggressively replace fluids to avoid shock & renal failure o Febrile Non-hemolytic Transfusion Reactions (FNHTR): Alloantibodies to WBC, platelets or other donor plasma antigens – occurs <6hrs after transfusion Symptoms Fever, rigors, facial flushing, headache, myalgia, hypotension Treatment Stop transfusion if fever >38OC – give antipyretics & anti-histamine If fever <38OC – continue w/transfusion but rate & give antipyretics o Allergic Non-hemolytic Transfusion Reactions: Alloantibodies (IgE) to proteins in donor plasma result in mast cell activation & histamine release MC in pts. w/history of multiple transfusions or multiparous women Symptoms Urticaria fever – can present as anaphylactic reaction in IgA deficient pts. Treatment Stop transfusion & give IV Diphenydramine, Epinephrine, Corticosteroids If reaction mild – slow transfusion rate & give Diphenhydramine o Delayed Hemolytic Transfusion Reactions: Due to alloantibodies to minor antigens such as Rh, Kell, Duffy or Kidd Occurs 5-7d after transfusion – antibody level at time of transfusion too low to cause hemolysis Antibody level later increases due to 2 O stimulus & causes extravascular hemolysis Symptoms Anemia & mild jaundice – no specific treatment required
MICROCYTIC ANEMIAS
Iron Deficiency Anemia (IDA) o Etiology: Chronic bleeding Menorrhagia or GI bleeding – R/O colon cancer in elderly pts. w/IDA Dietary Cow’s milk or “tea & toast” diet – MC in children & elderly 1
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Iron requirement Pregnancy Clinical Presentation Pallor, fatigue, brittle nails w/koilonychia, DOE, tachycardia, palpitations Diagnosis Ferritin (most reliable), TIBC, Transferrin, RDW Treatment: Iron Ferrous Sulfate/Gluconate/Fumarate – continue for 3+ months until ferritin normalizes Oral iron should be taken w/citrus juice to enhance absorption Venofer – IV iron if unable to tolerate or absorb oral iron If not responding to iron therapy obtain Hb electrophoresis to R/O thalassemia Blood transfusion Only in severe cases or if comorbid cardiopulmonary disease
β-Thalassemia o β-chain deficiency w/normal synthesis of α-chains – excess α-chains bind & damage RBC membrane o Thalassemia Major (Cooley's Anemia): Homozygous β-chain absent due to nonsense mutation (stop codon) – MC in Mediterraneans Clinical manifestations begin at 6-12 months age when HbA normally replaces HbF Clinical Presentation: Severe anemia & jaundice Stunted growth & development – hypogonadal dwarf Gross splenomegaly – due to extramedullary hematopoiesis BM expansion w/skeletal deformities – “crew cut” skull, chipmunk facies, pathologic Fx. Pigmented gallstones – evidence of Hb catabolism Diagnosis: Hb Electrophoresis HbF (90-100%) & HbA (0-10%) Skull XR “Hair-on-end” appearance Treatment: PRBC transfusions Required frequently to sustain life o If untreated death occurs within 1st few years of life 2O to progressive CHF Deferoxamine Fe chelation to prevent iron overload from frequent transfusions Allogenic BM Transplant o Thalassemia Minor: Heterozygous β-chain underproduced Asymptomatic or mild microcytic hypochromic anemia – no treatment required Hb Electrophoresis reveals HbF & HbA2 (>3.5%) o Thalassemia Intermedia Involves both β-globin genes w/intermediate severity anemia
α-Thalassemia o Synthesis of α-chains – remaining β-globin chains form abnormal Hb tetramers o Carriers (silent) 1 α-gene affected – asymptomatic w/normal Hb & no treatment o α-Thalassemia Minor (trait) Mutation/deletion of 2 α-genes - MC in African-Americans Mild microcytic hypochromic anemia & no treatment needed o HbH Disease (β4) 3 α-genes affected w/significant microcytic hypochromic anemia Hemolytic anemia & splenomegaly – treatment same as β-thalassemia major Hb electrophoresis reveals HbH o Hydrops Fetalis/Hb Barts (4) All 4 α-genes affected – fatal at birth or shortly after
Sideroblastic Anemia o Abnormality in RBC iron metabolism w/trapped iron in mitochondria of nucleated RBCs o Etiology: Hereditary X-linked defect in -Aminolevulinic acid synthase gene Glycine + Succinyl CoA unable to form -Aminolevulinic acid Rate-limiting step w/pyridoxine (B6) as cofactor Acquired Alcohol, Pb, INH (inhibits B6), Chloramphenicol o Clinical Presentation Anemia, hepatosplenomegaly, Fe overload syndrome o Diagnosis: Labs Iron, Ferritin, TIBC Histology Ringed sideroblasts in BM w/prussian-blue stain o Treatment Remove offending agents & administer B6 if needed 2
NORMOCYTIC ANEMIAS
Anemia of Chronic Disease (ACD) o Anemia of underproduction due to impaired iron utilization – can be normocytic or microcytic Occurs in setting of chronic infection, cancer, inflammation or trauma o Pathophysiology: Release of inflammatory cytokines has suppressive effect on erythropoiesis Hepcidin from liver causes release of iron from macrophages EPO normal or slightly elevated – but marrow unable to respond w/ erythropoiesis o Diagnosis Iron, TIBC, Transferrin, Ferritin, ESR, CRP – absent splenomegaly! o Treatment Treat underlying process & do not give iron
Aplastic Anemia o Pancytopenia caused by failure or destruction of myeloid stem cells in BM o Etiology: Idiopathic MCC & often T-cell mediated Drugs Chloramphenicol, Sulfonamides, Carbamazepine, Benzene, Radiation, Alkylating-agents Viral Parvovirus B19, EBV, CMV, VZV, HIV, HCV, HBV Genetic Fanconi’s anemia or Shwachman-Diamond syndrome o Clinical Presentation: Anemia, fatigue, pallor, dyspnea – absence of splenomegaly & LAD Thrombocytopenia – petechiae, easy bruising, mucosal bleeding Infections – due to neutropenia Complications – can progress to acute leukemia o Diagnosis: Pancytopenia w/ Reticulocytes BM Biopsy Hypocellular w/fatty infiltration – absent progenitors of all 3 hematopoietic lines o Treatment: Allogenic BMT Can cure 80-90% of pts. under age 50 Immunosuppressives Antithymocyte globulin, Cyclosporine, Prednisine – 60-70% remission
MACROCYTIC ANEMIAS
Megaloblastic Anemia Vitamin B12 (Cyanocobalamin) Deficiency o B12 is cofactor in 2 important reactions: Conversion of Homocysteine to Methionine Conversion of Methylmalonyl CoA to Succinyl CoA o Etiology: Pernicious anemia MCC in western hemisphere Auto-antibodies against gastric parietal cells causes achlorhydria & lack of intrinsic factor Parietal cells make IF which binds B12 & allows absorption by terminal ileum Poor diet MC in vegetarians & alcoholics Main dietary source is meat/fish & B12 stores in liver enough for 3+ yrs Chronic gastritis Leads to gastric mucosal atrophy Absorption Gastrectomy, Crohn's, Ileal resection Diphyllobothrium latum (fish tapeworm) Competes for B12 o Clinical Presentation: Anemia, stomatitis & glossitis Subacute-combined degeneration – distinguishes B12 from folate deficiency Irreversible demyelination of spinal cord Posterior columns – vibration sense, proprioception & 2-point discrimination Pyramidal tracts – hyperreflexia, spasticity, weakness, Babinski May cause urinary or fecal incontinence & impotence Peripheral neuropathy – usually symmetrical & affecting lower limbs > upper limbs May lead to confusion, delirium or dementia o Diagnosis: MCV >100, B12 (<100 pg/mL), Methylmalonic acid, Homocysteine 3
Methylmalonic acid seen only in B12 deficiency Peripheral Smear Hypersegmented neutrophils & oval macrocytes BM Biopsy Hypercellularity & nuclear-cytoplasmic asynchrony in RBC precursors Less mature nuclei than expected from development of cytoplasm Schilling Test Determines cause of cyanocobalamin deficiency Administer IM dose of unlabeled B12 to saturate binding sites Give oral radioactive B12 & measure urine + plasma B12 to see absorption Next, give another oral radioactive B12 dose w/addition of intrinsic factor o If no change in serum B12 after IF Malabsorption is cause o If B12 after addition of IF Pernicious anemia is cause Treatment Parenteral B12 once per month – be cautious of hypokalemia & rebound thrombocytosis
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Megaloblastic Anemia Folate Deficiency o Folic acid stores limited & inadequate intake over 3-month period can cause deficiency Dietary intake MCC of folate deficiency – esp. elderly & alcoholics Other Alcoholism, MTX, Phenytoin, pregnancy, hemolysis, hemodialysis o Clinical Presentation Same as B12 deficiency – but without neurologic manifestations o Diagnosis Folic acid & Homocysteine o Treatment Folic acid supplements
HEMOLYTIC ANEMIAS
Hemolytic Anemias (HA) o Premature destruction of RBCs – anemia results if RBC destruction > BM erythropoiesis o Classification: Hemolysis due to intrinsic RBC defects – most cases inherited: Hb abnormality Sickle-cell, HbC disease, Thalassemias Membrane defects Spherocytosis, PNH (paroxysmal nocturnal hemoglobinuria) Enzymes G6PD deficiency, Pyruvate-kinase deficiency Hemolysis external to RBC defects – most cases acquired: Mechanical Prosthetic valves, microangiopathic hemolytic anemia (MHA) Infection Malaria, Clostridium Other Immune-mediated, medications or toxins o Clinical Presentation Anemia, jaundice, hepatosplenomegaly, pigment gallstones o Diagnosis: Hb, Hct, Reticulocyte Count LDH – released when RBCs destroyed Unconjugated/Indirect Bilirubin – degradation of heme released from RBCs destruction Intravascular Hemolysis: Haptoglobin – released hemoglobin immediately binds haptoglobin Hemoglobinuria & urine Hemosiderin o Dark urine color indicates severe intravascular hemolysis o Hemoglobin levels exceed reabsorption capacity of PCT Extravascular Hemolysis: Haptoglobin normal – Hb does not escape into plasma Absent hemoglobinuria & urine hemosiderin Direct Coombs’ Detects IgG or complement on RBC surface o Add anti-IgG or anti-complement antibodies to pts. RBCs o If RBCs agglutinate – HDN, AIHA, AHTR Indirect Coombs’ Detects antibodies in serum that can recognize antigens on RBCs o Mix pt. serum w/donor RBC & Coombs serum (human anti-Ig) o If RBCs agglutinate – used for cross-matching recipient serum w/donor RBC o Treatment Treat underlying cause – PRBCs if severe anemia
Sickle Cell Anemia o Autosomal recessive, occurring when normal HbA replaced by mutant HbS Intrinsic defect causing extravascular hemolysis 4
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G6V HbS has uncharged Valine substituted for negative charged Glutamic acid at 6th position of β-chain Deoxyhemoglobin O2 causes HbS to polymerize causing RBCs to sickle Sickled RBCs obstruct small vessels, leading to ischemia & painful crises Precipitants – acidosis, hypoxemia, 2,3-DPG, temperature, dehydration Classification: Sickle Cell Trait Heterozygotes (HbAS) – 60-65% HbA & 35-40% HbS Resistance to malaria, non-anemic w/normal CBC & normal life expectancy 1/12 African’s carry sickle cell trait – also seen in Italians, Greeks & Saudi Arabians HbSC Compound heterozygote – mild anemia & spleen not always atrophic in adults Sickle Cell Disease (SCD) Homozygous (HbSS) – 90-95% HbS, 5-10% HbF & absent HbA Sickling occurs at pO2 of 80mmHg & life expectancy reduced by 25-30yrs Clinical Presentation: Bone crises Bone infarction causing severe pain – MC clinical manifestation Self-limiting lasting 2-7 days & involves multiple sites like tibia, humerus & femur Aplastic crisis Provoked by viral infections – MCC is Parvovirus B19 Treat w/blood transfusion – recovery in 7-10 days Dactylitis Avascular necrosis of metacarpal & metatarsal bones Painful swelling of dorsa of hands & feet – seen in infancy by 4-6 months Splenomegaly Seen in childhood – spleen no longer palpable by age 4 Autosplenectomy Repeated splenic infarctions – spleen reduced to small, calcified remnant Results in Howell-Jolly bodies – basophilic nuclear remnants in RBC Splenic sequestration crisis MC in children w/intact spleens – potentially fatal Sudden pooling of blood into spleen causing rapid splenomegaly & hypovolemic shock Infections Asplenia causes susceptibility to encapsulated bacteria – H. influenzae, S. pneum. Osteomyelitis – caused by Salmonella paratyphi Avascular joint necrosis MC in femoral head & humeral head Pigmented gallstones Due to hemolysis Priapism Erection due to vaso-occlusion – sustained priapism >3hrs is medical emergency CVA Due to cerebral thrombosis Ophthalmologic Retinal infarcts & detachment, vitreous hemorrhage, proliferative retinopathy Renal papillary necrosis w/hematuria Painless & seen in up to 20% of cases Leg ulcers Vaso-occlusion of superficial leg vessels – commonly in lateral malleoli Acute chest syndrome Due to repeated episodes of pulmonary infarctions Mimics pneumonia – chest pain, resp. distress, pulmonary infiltrates & hypoxia CHF High-output heart failure may occur over time 2O to anemia Diagnosis Hb Electrophoresis Treatment: Hydroxyurea HbF production reduces sickling – cytotoxic & may cause BM suppression Painful crises Morphine + Fluids (to viscosity) + O2 PRBC transfusion Only in severe cases – CNS, cardiac or respiratory manifestations Antibiotics If infection suspected – Ceftriaxone or Cefotaxime Preventative: Avoid high altitudes – low oxygen tension can precipitate crisis Maintain fluid intake – dehydration can precipitate crisis Vaccinations against S. pneumoniae, H. influenzae & N. meningitidis Penicillin prophylactically from 4 months until age 6
Hereditary Spherocytosis o Autosomal dominant defect causing spectrin levels – MC hereditary HA Intrinsic defect causing extravascular hemolysis o RBC membrane surface area without reduction in RBC volume necessitates spherical shape Spherical RBCs become trapped & destroyed in spleen by macrophages o Clinical Presentation: Hemolytic anemia, jaundice, splenomegaly, calcium-bilirubinate gallstones Aplastic crisis w/parvovirus B19 infection o Diagnosis: Reticulocyte count, MCHC, RDW, LDH 5
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Peripheral Smear Spherocytes w/no central pallor Direct Coombs Helpful for distinguishing from AIHA – also has spherocytes Osmotic Fragility Test RBC lysis in hypotonic saline Treatment Splenectomy w/vaccination against encapsulated organisms
Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency o X-linked recessive enzyme deficiency – intrinsic defect w/extravascular hemolysis Precipitants – infection, fava beans or drugs (Sulfa, Nitrofurantoin, Primaquine, Dimercaprol) o Pathophysiology: G6PD NADPH & Glutathion (GSH) H2O2 RBC susceptibility to oxidant stress GSH neutralizes H2O2 preventing oxidization of Hb & formation of Heinz bodies Heinz bodies – attach to RBC membranes causing flexibility & leads to splenic RBC sequestration Bite cells – form after splenic macrophages remove heinz bodies from RBCs o Classification: A-Variant G6PD deficiency Mild form seen in 10% of African-American men Hemolytic episodes usually self-limited & involves only older RBCs o Younger RBCs spared & have sufficient G6PD to prevent RBC destruction Protection against malaria (P. falciparum) Severe G6PD deficiency MC in Mediterranean populations Both young & old RBCs are G6PD-deficient – results in severe HA o Clinical Presentation Episodic HA, jaundice & dark urine o Diagnosis: Peripheral Smear Bite cells & Heinz bodies G6PD assay Deficient NADPH – do not test in acute crisis as reticulocytes have G6PD levels o Treatment RBC transfusions if necessary
Paroxysmal Nocturnal Hemoglobinuria (PNH) o Acquired disorder caused by deficiency of GPI anchor protein – intrinsic defect w/intravascular hemolysis o Pathophysiology: GPI links complement-inactivating decay accelerating factor (DAF/CD55) to cell membranes DAF destabilizes C3 & C5 convertase adhering to membranes of RBCs, WBCs & platelets GPI Unanchored DAF Complement-mediated RBC lysis o Clinical Presentation: Hemoglobinuria – respiratory acidosis during sleep causes complement attachment Venous thrombosis – esp. hepatic vein (Budd-Chiari syndrome) o Diagnosis: LDH & urine Hemosiderin Flow Cytometry For CD55 (DAF) & CD59 proteins – sensitive & specific for PNH Ham's Test Pts. cells incubated in acidified serum triggering alternative complement pathway Results in lysis of PNH cells – but not normal cells Sugar Water Test Pts. serum mixed in sucrose – hemolysis will occur in PNH o Treatment: Corticosteroids Initial therapy – some do not respond Eculizumab Inhibits complement effect on RBCs
Autoimmune Hemolytic Anemia (AIHA) o Auto-antibodies toward RBC membrane antigens leading to RBC destruction Ab type (IgG or IgM) determines prognosis, site of RBC destruction & response to treatment Often mild & treatment rarely required – only if hemolysis severe o Warm AIHA: IgG auto-antibody binds optimally to RBC membranes at 37°C - MC than Cold AIHA Extravascular hemolysis Spleen is primary site of RBC sequestration causing splenomegaly Etiology: Primary Idiopathic Secondary CLL, lymphomas, SLE, viral infections or drug-induced o Type I drug-induced Hapten-mediated – Penicillin, Cephalosporins o Type II drug-induced Immune-complex mediated – Quinine, Sulfas, Rifampin o Type III drug-induced “True” anti-RBC Ab – Methyldopa 6
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Cold AIHA: IgM auto-antibody binds RBC membranes at cold temperatures between 0°C–5°C Intravascular hemolysis Due to complement activation & primary site of sequestration is liver Etiology: Primary Idiopathic – MC in elderly Secondary Waldenström's macroglobulinemia or infection w/Mycoplasma or EBV Clinical Presentation: Anemia, fatigue, pallor, jaundice, dark urine Cold AIHA – cyanosis of ears, nose, fingers & toes Diagnosis: Direct Coombs Anti-Ig Abs added to pts. RBCs – will agglutinate if RBCs coated w/Ig Cold Agglutinin Titer in Cold AIHA Treatment: Warm AIHA Corticosteroids – mainstay of therapy Splenectomy – if unresponsive to steroids Cold AIHA Avoid exposure to cold – prevents bouts of hemolysis Immunosuppressants for severe cases Azathioprine, Cyclosporine, Cyclophosphamide Rituximab Anti-CD20 Ab – may be beneficial
HEMOSTASIS
Phases of Hemostasis o 1) Primary Hemostasis Vessel injury results in collagen/subendothelial matrix exposure & release of vasoconstrictors Blood flow impeded & platelets come into contact w/damaged vessel wall Adhesion Platelets adhere to subendothelium via vWF Activation Platelets activated causing release of ADP & thromboxane A2 Aggregation These factors aggregate more platelets & form hemostatic plug o 2) Secondary Hemostasis Platelet plug reinforced by production of fibrin clot in secondary hemostasis Extrinsic pathway Initiation of coagulation in vivo Intrinsic pathway Amplification once coagulation has started o 3) Resolution Fibrin stabilization & fibrinolysis
Extrinsic Coagulation Pathway o Fast reaction caused by release of Tissue Factor from damaged endothelial cells o Cascade involves factors 7, 10, 5 Defects cause PT – normal PT = 11-24 sec o Pathway steps: 1) Tissue Factor cleaves VII VIIa (7a) 2) VIIa cleaves X Xa (10a) 3) Xa w/cofactor Va (5a) cleaves Prothrombin (II) Thrombin (IIa) Thrombin in return cleaves V Va (5a) 4) Thrombin cleaves Fibrinogen (I) Fibrin = Clot formation
Intrinsic Coagulation Pathway o Slow reaction caused by contact activation – involves factors 12, 11, 9, 8, 10, 5 Defects cause PTT – normal aPTT = 22-35 sec o Vitamin K crucial for -carboxyglutamate residues on factors 2, 7, 9 & 10 o Pathway steps: 1) Contact activation cleaves XII (Hageman Factor) XIIa (12a) 2) XIIa cleaves XI XIa (11a) 3) XIa cleaves IX IXa (9a) 4) IXa w/cofactor VIIIa (8a) cleaves X Xa VIIIa formed when Thrombin cleaves VIII VIIIa 5) Xa w/cofactor Va cleaves Prothrombin Thrombin Thrombin in return cleaves V Va (5a) 6) Thrombin cleaves Fibrinogen Fibrin = Clot formation 7
DISORDER OF PRIMARY HEMOSTASIS
Heparin-Induced Thrombocytopenia (HIT) o HIT Type 1 Non-immune as Heparin directly causes platelet aggregation <48hrs after administration Onset in 24-72hrs w/no thrombosis & no treatment needed – may continue Heparin use o HIT Type 2 Heparin induces antibody-mediated injury to platelets 3-12 days after initiating use Ab recognizes complex of heparin & platelet factor 4 (PF4) leading to platelet activation 50% reduction in platelets within 5-15 days – can develop in hrs if previously exposed to heparin o Clinical Presentation: Risk of thrombosis 30% – bleeding complications uncommon Venous DVT, PE, limb gangrene, cerebral sinus thrombosis Arterial MI, stroke, acute limb ischemia, organ infarct Heparin-induced skin necrosis w/LMWH Acute inflammatory reactions – fever, chills, flushing, etc. o Diagnosis: 14C Serotonin Assay Donor platelets w/14C serotonin & heparin w/pts. plasma ELISA for HIT-Ig More sensitive – but less specific than serotonin assay o Treatment: Immediate discontinuation of Heparin – do not substitute LMWH as 90% cross-reactivity Alternative anticoagulation: Lepirudin Recombinant Hirudin – avoid in renal disease Argatroban Thrombin inhibitor – monitor w/aPTT & use caution in liver disease Danaparoid Inhibition of activated factor X
Immune Thrombocytopenic Purpura (ITP) o Autoimmune anti-GpIIb/IIIa Abs (IgG) bind platelet surface & then removed by splenic macrophages o Acute ITP Seen in children w/abrupt onset of bleeding & preceded by recent infection Self-limited – 80% resolve spontaneously within 6 months o Chronic ITP Seen in adults, F>M = 3:1 w/insidious onset of bleeding & spontaneous remissions rare Often ass. w/lymphoma, CLL, HIV, or SLE o Clinical Presentation BT, petechiae, ecchymoses, mucosal bleeding – absent splenomegaly o Diagnosis: PC, BT w/normal PT & aPPT BM Aspirate Megakaryocytes Anti-GpIIb/IIIa antibodies o Treatment: Corticosteroids Prednisone initial therapy in most cases IVIG Platelet uptake & destruction by spleen by saturating reticuloendothelial binding sites Indicated if PC <20,000/mm3 or if at risk of severe bleeding RhoGAM – can be used as alternative in Rh pts. Splenectomy Indicated in chronic ITP refractory to steroids – 70-80% remission Platelet transfusion Not beneficial – but may be given during serious hemorrhagic episodes
Thrombotic Thrombocytopenic Purpura (TTP) o Rare disorder of platelet consumption due to deficiency of ADAMTS 13 – life threatening emergency o Pathophysiology: ADAMTS 13 is vWF metalloprotease involved in degradation of vWF multimers vWF multimers Platelet aggregation & thrombosis Platelet consumption Leads to formation of hyaline microthrombi – platelet thrombi occluding small vessels Can effect any organ & cause mechanical damage to RBCs causing schistocytes o Clinical Presentation Thrombocytopenia, bleeding, fever, acute renal failure, altered mental status o Diagnosis: PC, BT w/normal PT & aPTT – no consumption of clotting factors LDH, Haptoglobin, Schistocytes – due to microangiopathic hemolytic anemia o Treatment: Plasmapheresis immediately Corticosteroids Splenectomy Beneficial in some cases Platelet transfusions Contraindicated due to microvascular thrombosis 8
von Willebrand's Disease (vWD) o Autosomal dominant deficiency or defect of vWF – MC inherited bleeding disorder vWF mediates binding of platelet GpIb to subendothelial collagen Also carrier of factor VIII in blood – associated w/antigenic protein of factor 8 o Classification: Type 1 Levels of vWF – MC type Type 2 Exhibits qualitative abnormalities – dysfunctional vWF Type 3 Autosomal recessive w/absent vWF – very severe & least common o Clinical Presentation: Bleeding – epistaxis, bruising, gingival bleeding – avoid use of Aspirin Menorrhagia – affects >50% of women w/vWD No spontaneous hemarthrosis – bleeding much milder than Hemophilia o Diagnosis: vWF, Factor VIII antigen, BT, PTT & normal PC Ristocetin-induced aggregation Ristocetin activates GpIb receptors on platelets o Treatment: Desmopressin (DDAVP) Induces endothelial cells to secrete vWF – 1st line for type 1 vWD Type 2 may respond to DDAVP – but not effective for type 3 Factor VIII concentrates Contains high-molecular-weight vWF Effective for type 3 vWD – but given to all types after major trauma or during surgery Cryoprecipitate Not recommended due to risk of viral transmission
Bernard-Soulier Disease o Autosomal recessive disorder in platelet adhesion due to deficiency of platelet glycoprotein GpIb GpIb responsible for binding platelet to subendothelial collagen via vWF o Diagnosis BT, PC & abnormally large-sized platelets on blood film
Glanzmann's Thrombasthenia o Autosomal recessive disorder of platelet aggregation due to deficiency in platelet glycoprotein GPIIb/IIIa GPIIb/IIIa responsible for platelet to platelet aggregation via fibrinogen o Diagnosis BT & PC normal
DISORDERS OF SECONDARY HEMOSTASIS
Hemophilia A o X-linked recessive deficiency or defect of factor VIII causing bleeding – predominately in males o Clinical Presentation: Hemarthrosis – MC in knees but any joint can be involved Progressive joint destruction 2O to recurrent hemarthroses Maintaining normal factor VIII levels can minimize joint destruction Hematomas, hematuria, hemospermia Risk intracranial bleeding – any head trauma requires urgent evaluation o Diagnosis PTT & Factor VIII o Treatment: Factor VIII concentrate For more severe cases – mainstay of therapy Desmopressin (DDAVP) For mild cases & can factor VIII level fourfold Analgesics For hemarthroses but avoid NSAIDs – also immobilization of joint & ice packs
Hemophilia B o X-linked recessive deficiency of factor IX – also called Christmas disease o Much less common than Hemophilia A – but clinical features identical in both o Treatment Factor IX concentrate – DDAVP not beneficial
Disseminated Intravascular Coagulation (DIC) o Abnormal activation of coagulation sequence leading to formation of microthrombi in vessels Thrombi cause consumption of platelets, fibrin & coagulation factors – leads to bleeding o Activation of fibrinolytic mechanisms leads to hemorrhage – bleeding & thrombosis occur simultaneously 9
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Etiology: Infection MCC – esp. GN sepsis, but any infection can cause DIC Obstetric Abruptio placentae, amniotic fluid emboli, retained dead fetus Placenta & uterus have tissue factor levels Tissue injury Major trauma, surgery, burns, fractures Malignancy APL M3 or solid tumors – esp. lungs, pancreas, prostate, GI Other Shock, circulatory collapse, fat embolism, antiphospholipid Ab syndrome, snake venom Clinical Presentation: Microvascular thrombosis: Skin – focal ischemia, superficial gangrene Neurologic – multifocal infarcts, delirium, coma, seizures Renal – oliguria, azotemia, cortical necrosis Pulmonary – ARDS GI – acute ulcers & bowel infarction RBC – microangiopathic hemolysis Hemorrhagic diathesis: Skin – petechiae, ecchymosis, oozing from puncture/incision sites Mucosal – gingival oozing, epistaxis, massive bleeding Neurologic – intracranial bleeding is common cause of death Renal – hematuria Diagnosis: BT, PT, PTT, PC, Fibrinogen D-dimers Fibrin degradation products (FDP) – due to activation of fibrinolytic system Peripheral Smear Schistocytes – due to mechanical RBC damage Treatment: Hemorrhage FFP, Cryoprecipitate, Platelet transfusions Thrombosis LMWH – inhibits clotting & prevents consumption of factors Use is controversial & given only in rare cases where thrombosis dominates
Vitamin K Deficiency o Several clotting factors depend on vitamin K as cofactor for synthesis in liver Factors 2, 7, 9, 10 + Protein C & S Post-translational modification via gamma-carboxylation Source – leafy greens & synthesis by GI flora – newborns lack flora & require vitamin K injection o Etiology: Antibiotics Suppress gut flora which supplies 50% of vitamin K Diet TPN, poor diet, alcoholics Malabsorption Fat-soluble vitamin absorption Warfarin Vitamin K antagonist via inhibition of epoxide reductase o Diagnosis PT & PTT – prolonged PT initial finding since factor VII has shortest ½ life o Treatment: Vitamin K If INR between 4.5 to 10 w/no actively bleeding – PT should improve within 24hrs FFP Given simultaneously in severe bleeding
Coagulopathy of Liver Disease o Seen in severe liver disease – all clotting factors produced by liver except factor VIII Bleeding – GI bleeds MC due to varices from portal HTN o Etiology: Liver disease – synthesis of clotting factors Cholestasis – causes vitamin K absorption leading to deficiency Hypersplenism – splenomegaly due to portal HTN & causing thrombocytopenia o Diagnosis PT & PTT – no improvement w/vitamin K o Treatment FFP – contains all clotting factors
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HYPERCOAGULABLE DISORDERS
Antithrombin III Deficiency o Autosomal dominant inheritance or urinary losses in nephrotic syndrome o Antithrombin slowly inactivates thrombin in absence of heparin No response to heparin in AT III deficiency – heparin requires presence of AT III o Classification Type I = AT levels & Type II = AT activity o Deficiency may result in resistance to unfractionated heparin – LMWH must be used
Antiphospholipid Antibody Syndrome (APS) o Hypercoagulable vasculopathy due to antiphospholipid Abs interfering w/coagulation cascade o Classification: 1O APS Idiopathic – occurs in absence of other disease 2O APS Associated w/any of the following: Collagen vascular disease – esp. SLE Drugs – Hydralazine, Procainamide, Phenytoin, IFN, Quinidine Infections – HIV, TB, hepatitis C, infectious mononucleosis Catastrophic APS (Asherson’s syndrome) High mortality rate – up to 50% Develops within 1 week of thrombotic occlusion in ≥3 organ systems o Clinical Presentation: Recurrent thromboembolic events – DVT, PE, TIA, MI, renal vein thrombosis Recurrent spontaneous abortions Thrombocytopenia, hemolytic anemia, livedo reticularis o Diagnosis Lupus anticoagulant, Anticardiolipin Ab, Anti-2 glycoprotein-I Ab o Treatment: Thrombosis Lifelong anticoagulation w/Warfarin Target INR 2.0-3.0 for 1st venous event & >3.0 for recurrent or arterial event Recurrent fetal loss Heparin/LMWH Aspirin – given during pregnancy Catastrophic APS Corticosteroids, Anticoagulation, Cyclophosphamide & Plasmapheresis
Protein C Deficiency: o Autosomal dominant deficiency leads to unregulated fibrin synthesis – Protein C inhibits factors V & VIII o Homozygous Neonatal purpura fulminans o Heterozygous Type I = Protein C levels & Type II = Protein C activity o Acquired Warfarin, liver disease, sepsis, DIC o Risk of hemorrhagic skin necrosis following administration of Warfarin
Protein S Deficiency: o Protein S is cofactor of Protein C – deficiency causes Protein C activity o Type I Free & total Protein S levels o Type II Protein S activity o Type III Free Protein S levels o Acquired Liver disease, DIC, pregnancy, nephrotic syndrome, inflammatory diseases
Factor V Leiden: o MCC of hereditary thrombophilia – 5% of population are heterozygotes o Factor V gene mutation (R506Q) results in resistance to inactivation of factor Va by activated Protein C Causes unregulated Prothrombin activation leading to thrombosis
Prothrombin Gene Mutation o Mutation in 3’ untranslated region – G to A transposition in prothrombin gene promoter region o Results in levels of prothrombin causing thrombin generation
Hyperhomocystinemia o Genetic or acquired abnormality – homocysteine levels found in following: B12/B6/folate deficiency, drugs - MTX, Phenytoin, Theophylline, CRF, hypothyroidism, malignancy o Treatment Folate supplements – can plasma homocysteine by 50% 11
PLASMA CELL DISORDERS
Multiple Myeloma o Primary neoplastic proliferation of single plasma cell line producing monoclonal immunoglobulin 95% produce M-protein – 50% IgG, 20% IgA, 2% IgD or 0.5% IgM 15-20% produce free light chains – found in either serum or urine as Bence-Jones protein o Poor prognosis – 5yr survival rate 10% & if treated median survival is 2-4yrs o Epidemiology M>F, median age of diagnosis 68yrs, risk in African-Americans o Clinical Presentation: Bone resorption 2O to neoplastic release of RANKL causing osteoclast activation Bone pain – MC in spine & ribs w/bony tenderness Risk of pathologic fractures & height due to vertebrae collapse Classic lytic lesions – skull, spine, proximal long bones, ribs Hypercalcemia – weakness, N/V, confusion, constipation, polyuria, polydipsia BM suppression 2O to accumulation of abnormal plasma cells Infections – MCC of death & due to suppression of normal plasma cell function o MC pathogens are S. pneumoniae & GNs Anemia – weakness, fatigue, pallor Thrombocytopenia – bleeding, petechiae, purpura Paraprotein 2O to abnormal production by plasma cells Renal failure – MC is cast nephropathy Hyperviscosity – headaches, stroke, angina, MI Amyloidosis – accumulation of insoluble fibrillar protein in any organ tissue o Cardiac – diastolic dysfunction, arrhythmias, syncope, sudden death o GI – malabsorption, beefy large or laterally scalloped tongue o Neurologic – orthostatic hypotension, carpal tunnel, neuropathies Extramedullary plasmacytoma Soft tissue mass of monoclonal plasma cells w/purplish color Radiculopathy Can be due to vertebral fracture or extramedullary plasmacytoma Spinal cord compression in 15% - medical emergency Acquired vWD Bleeding disorder due to absorption of vWF by plasma cells o Diagnosis: Serum Protein Electrophoresis (SPEP) Monoclonal protein spike in almost all cases Urine Protein Electrophoresis (UPEP) Bence-Jones protein Peripheral Smear Rouleaux formation – hyperglobulinemia causes RBCs to stick together Labs ESR, 2-microglobulin, Ca2+, PC, Anemia, Leukopenia Radiographs Lytic bone lesions w/puched-out appearance BM Biopsy More than 10% plasma cells – confirms diagnosis o Treatment: Incurable Chemotherapy w/alkylating agents – preferred initial therapy Autologous Stem Cell Transplant (ASCT) For pts. <75yrs – preferred over BMT Transplant candidates – start Thalidomide & Dexamethasone Non-candidates – start Melphalon, Prednisone & Thalidomide Bortezomib Protease inhibitor – useful for relapsed myeloma or combine w/other drugs
Waldenström's Macroglobulinemia o Malignant proliferation of plasmacytoid lymphocytes – chronic disorder of elderly w/median age 64yrs Cells produce IgM para-protein – very large & causes hyperviscosity of blood o Clinical Presentation: Lymphadenopathy & hepatosplenomegaly – LAD not seen in MM Weakness, fatigue, oronasal bleeding, weight loss, recurrent infections, dyspnea, Absence of bone lesions & no hypercalcemia – helps distinguish from MM Hyperviscosity syndrome – due to IgM that’s mostly confined to intravascular space Headache, ataxia, retinal vessel dilation, rouleaux formation CHF – due to triad of anemia, hyperviscosity & plasma volume expansion o Diagnosis: M-spike IgM >5g/dL Bence Jones proteinuria – 10% of cases BM Aspirate Reveals plasmacytoid lymphocytes 12
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Treatment: Incurable Chemotherapy w/alkylating agents Hyperviscosity syndrome Plasmapheresis
Monoclonal Gammopathy of Undetermined Significance (MGUS) o Presence of serum M-protein in absence of any clinical manifestations of myeloma MC in elderly affecting 3% of population >70yrs – no treatment required o Asymptomatic – less than 20% develop MM after 10-15yrs o Hematologic malignancy develops in <1% each year – risk if M-protein ≥15g/L or if IgA/IgM MGUS o Diagnosis SPEP shows M-protein <30g/L & BM Biopsy reveals <10% plasma cells
LYMPHOMAS
Ann-Arbor Lymphoma Staging o Stage I Confined to single lymph node o Stage II Involvement of 2 or more lymph nodes, but confined to same side of diaphragm o Stage III Involvement of lymph node regions on both sides of diaphragm o Stage IV Dissemination to extralymphatic organs including BM o Subtype A Absence of B symptoms o Subtype B Constitutional symptoms – unexplained fever, weight loss & night sweats
Hodgkin's Lymphoma o Localized involvement of single group of lymph nodes w/contiguous spread to adjacent LNs o Bimodal age distribution w/peaks at 15-30yrs & >50yrs – EBV association in up to 50% of cases o Histologic Classification: Nodular Sclerosis (40-60%) Collagen banding & Lacunar cells – only type MC in females Mixed Cellularity (20-40%) Strong ass. w/EBV & large # of RS cells in pleomorphic background Lymphocyte Predominant (10-20%) Few RS cells & many B-cells Lymphocyte Depletion (1-10%) Lacking in mix of reactive cells & has worst prognosis o Clinical Presentation: Painless LAD – cervical/supraclavicular (MC), axillary, mediastinal, inguinal Mediastinal mass often found on routine CXR B-symptoms – fever, night sweats & weight loss Splenomegaly (50%) hepatomegaly o Diagnosis: LN Biopsy Reed Sternberg (RS) cells – required to make diagnosis RS cells – giant neoplastic cell w/B-cell origin – CD15 & CD30 “Owl’s eye” appearance – two or more nuclei w/mirror image of halves CXR & CT Detects LN involvement Labs WBCs & Eosinophilia - LDH indicates adverse prognosis Presence of inflammatory cells distinguishes Hodgkin's from NHL o Treatment: Chemotherapy + Radiation = Cure rate >70% ABVD Adriamycin, Bleomycin, Vinblastine & Dacarbazine ABVD preferred chemotherapy due to less adverse affects BEACOPP Bleomycin, Etoposide, Adriamycin, Cyclophosphamide, Vincristine, Procarbazine, Prednisone Relapse or Resistance High-dose Chemotherapy + BMT
Non-Hodgkin's Lymphoma (NHL) o Malignant transformation of B or T lymphocytes or their precursors in lymphatic system Involves multiple, peripheral nodes & may spread to blood or bone marrow o Twice as common as Hodgkin's – NHL is 6th MCC of cancer-related deaths in USA o B-cell Lymphomas (85%): Burkitt’s Lymphoma Associated with t(8;14) & c-Myc activation – MC in children & young adults African (Endemic) Type Massive jaw LAD & ass. w/EBV American (Sporadic) Type GI & para-aortic LNs – hepatomegaly & abdominal masses 13
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Histology “Starry-sky” – sheets of lymphocytes w/interspersed macrophages Very aggressive w/poor prognosis unless intense chemotherapy Diffuse Large B-cell Lymphoma Predominantly B-cell origin – 20% mature T-cell origin MC adult NHL – 20% of cases seen in children High-grade, aggressive & presents as large extranodal mass Richter’s transformation 5% of CLL cases transform into DLBCL Mantle Cell Lymphoma Associated with t(11;14) w/overexpression of cyclin D1 & bcl-1 activation Indolent course & MC in older males – M>F = 4:1 Follicular Lymphoma Associated with t(14;18) causing bcl-2 overexpression an anti-apoptotic gene MC NHL w/mean age of onset at 55yrs – painless peripheral LAD Indolent – incurable & may transform into diffuse large cell lymphoma T-cell Lymphomas (15%): Adult T-cell Lymphoma Aggressive w/cutaneous lesions due to HTLV-1 – MC in Japan, West Africa & Caribbean Mycosis Fungoides Cutaneous eczematoid lesions & erythroderma – cribriform shaped CD4 lymphocytes Sézary syndrome Late stage w/dissemination to LNs & blood Clinical Presentation: Lymphadenopathy – painless, firm, mobile & may rapidly enlarge Retroperitoneal & mesenteric involvement – hepatosplenomegaly B-symptoms – less common than in Hodgkin's Oropharyngeal involvement (5-10%) – sore throat & obstructive apnea BM involvement – may cause anemia, thrombocytopenia or neutropenia w/ infections CNS involvement – often seen in HIV pts. Diagnosis: LN Biopsy Definitive – biopsy any node >1cm present for >4wks & not attributed to infection CXR May reveal hilar or mediastinal lymphadenopathy CT Assess extent of spread & response to treatment Treatment: Indolent Incurable – Follicular & Mantle cell lymphoma Localized disease Radiation Advanced stage Chemotherapy Rituximab if B-cell origin Aggressive Curable – Diffuse large B-cell lymphoma Chemotherapy Rituximab if B-cell origin CHOP Cyclophosphamide, Hydroxydaunomycin (Doxorubicin), Oncovin (Vincristine), Prednisone CNS prophylaxis High-dose Methotrexate Relapse or Resistance High dose chemotherapy & BMT Highly-aggressive Burkitt’s lymphoma – Chemotherapy w/short intensive bursts High risk of tumor lysis syndrome upon treatment
LEUKEMIAS
Acute Myelogenous Leukemia (AML) o Neoplasm of myelogenous progenitor cells – Myeloblasts due to failure of differentiation o 80% of adult acute leukemias w/average onset at 65yrs – accounts for 10-15% of childhood leukemia o Etiology Idiopathic or 2O to myeloproliferative disorders, radiation, chemotherapy w/alkylating agents o Classification: M1 Myeloblastic without maturation M2 Myeloblastic w/maturation M3 Acute Promyelocytic Leukemia (APL) Accumulation of immature granulocytes called promyelocytes Associated with t(15;17) on retinoic acid receptor (RAR) gene M4 Myelomonocytic M5 Monocytic 14
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Clinical Presentation: Anemia & neutropenia (even w/normal WBC) Leads to infections & fever Thrombocytopenia – ass. w/DIC in APL Skeletal pain w/bony tenderness – esp. sternum Organ infiltration: Gingival hypertrophy & leukemia cutis Splenomegaly w/early satiety & LUQ fullness Roth spots & cotton wool spots Leukostasis/Hyperleukosis syndrome – medical emergency Large # of blasts interfere w/circulation leading to hypoxia & hemorrhage Can cause diffuse pulmonary infiltrates, CNS bleeding, respiratory distress or AMS Diagnosis: Peripheral Smear Auer rods – peroxidase cytoplasmic inclusions in myeloblasts BM Aspirate Blast count >20% - normally <5% Labs LDH, Uric acid, PO4 – released by leukemic blasts Treatment: Chemotherapy To induce complete remission of AML – rapidly fatal without treatment Ex. Cytarabine w/Anthracycline (Daunorubicin) Poor prognosis if low response to initial induction chemotherapy Consolidation therapy To prevent recurrence Intensive consolidation chemotherapy BM/Stem cell transplantation – autologous or allogeneic – up to 50% cure rate APL (M3) All-trans-retinoic acid (ATRA) – vitamin A derivative that induces differentiation Treatment of M3 can release auer rods – may lead to DIC & bleeding Severe infections Consider acceleration w/hematopoietic growth factors – ex. G-CSF Prognosis Remission rate of 70-80% if <60yrs & 50% if >60yrs – 5yr survival rate 40%
Acute Lymphoblastic Leukemia (ALL) o Malignancy of early lymphoid precursors BM replaced by Lymphoblasts MC malignancy in children w/75% <6yrs age – second peak at age 40 o Classification: Pre-B-cell ALL Associated with t(12;21), TdT , CALLA , CD10 MC subtype – may spread to testicles Pre-T-cell ALL TdT & CD10 negative Mediastinal mass can compress SVC, esophagus or trachea o Clinical Presentation: BM suppression – anemia, thrombocytopenia & neutropenia Fever, tender bones, LAD, hepatosplenomegaly, infections Meningeal signs – headache, N/V, visual problems o Diagnosis: WBC – seen in 50% of cases Peripheral Smear Lymphoblasts & PAS w/no granules Cytogenetics Philadelphia (Ph) chromosome – 25% of adult ALL cases o Treatment: Chemotherapy To induce complete remission w/undetectable leukemic blasts Dana-Farber – Vincristine, Prednisone, MTX, Lencovorin, L-Asparaginase, Ara-C Consolidation – continuing same chemotherapy to eliminate subclinical leukemic cells Intensification – high-doses of different chemo. drugs to eliminate cells w/resistance Maintenance – low-dose intermittent chemotherapy over 2-3yrs to prevent relapse Imatinib (Gleevec) Add if Ph chromosome – bcr-abl tyrosine kinase inhibitor bcr-abl fusion gene ass. w/chemotherapeutic resistance Hematopoietic stem cell transplantation Potentially curative o Prognosis: Most responsive leukemia to therapy – 80% long-term remission in children Higher cure rates in children due to prevalence of bcr-abl fusion gene Poor prognostic indicators Age <2 or >9, WBC >105/mm3 or B-cell phenotype 15
Chronic Lymphocytic Leukemia (CLL) o MC leukemia occurring after age 50 & MC leukemia in western world – median age of onset 65yrs & M>F o Monoclonal proliferation of B-cells – morphologically mature but functionally defective Mature B-cells do not differentiate into plasma cells causing hypogammaglobulinemia Accumulation of neoplastic lymphocytes in blood, bone marrow, lymph nodes & spleen o Small Lymphocytic Lymphoma (SLL) same as CLL – except CLL has peripheral blood lymphocytosis o Prognosis Incurable – but slow progression w/9yr median survival o Clinical Presentation: Asymptomatic – often discovered on routine CBC due to lymphocytosis B-symptoms (10%) – weight loss, fatigue, fevers >38OC, night sweats Lymphadenopathy (50-90%), splenomegaly (25-50%) & hepatomegaly (15-25%) Richter’s transformation Aggressive transformation to DLBCL in 5% of cases o Diagnosis: CBC Lymphocytosis – WBC 50,000–200,000 Peripheral Smear Smudge cells – leukemic cells "beaten up" in blood Coombs Warm AIHA – IgG mediated extravascular hemolysis causing splenomegaly BM Aspirate Lymphocytes account for >30% of all nucleated cells 3 patterns of lymphocytic BM infiltration – interstitial, diffuse - worst prognosis & mixed o Treatment: Chemotherapy & Ritxuimab Little effect on overall survival – given for symptomatic relief Corticosteroids & IVIG For autoimmune phenomena
Chronic Myeloid Leukemia (CML) o Myeloproliferative disorder of granulocytic line w/no loss of ability to differentiate – MC in adults 30-60yr >90% w/Philadelphia chromosome t(9;22) causing bcr-abl fusion bcr-abl ass. w/tyrosine-kinase activation – leads to cell division & inhibition of apoptosis o Clinical Phases: Chronic phase Easily controlled – 85% diagnosed here Few blasts (<5%) w/slightly eosinophils & basophils – no significant symptoms Accelerated phase Impaired neutrophil differentiation – difficult to control Circulating blasts (10-20%) w/ peripheral basophils causing pruritis Blast crisis Aggressive course – blasts fail to differentiate & >20% in peripheral blood or BM Large foci of blasts in BM & extramedullary blast proliferation Evolution to acute leukemia – 1/3 to ALL & 2/3 to AML o Clinical Presentation: Asymptomatic – often discovered on routine CBC Nonspecific – fatigue, weight loss, malaise, excessive sweating, fever Splenomegaly – MC physical finding & due to extramedullary hematopoiesis 2O to splenic involvement – early satiety, LUQ pain/fullness, referred shoulder pain Bleeding & easy bruising – due to platelet dysfunction Pruritus – due to histamine from basophils o Diagnosis: Leukocytosis WBCs 50,000–200,000 w/left shift toward granulocytes LAP Differentiates CML from leukemoid reaction – no splenomegaly, LAP, infection Peripheral Smear Immature granulocytes, Eosinophilia & Basophilia Thrombocytosis Only leukemia w/PC – thrombocytopenia may be seen in accelerated phases o Treatment: Imatinib (Gleevec) Inhibits proliferation & induces apoptosis – success need for BMT Alternatives if unresponsive to Imatinib: o Dasatinib Tyrosine kinase & src dual inhibitor o Nilotinib Selective bcr-abl inhibitor Complete cytogenetic response (CCR) on Imatinib = 6yr survival >90% o NOT achieving CCR on Imatinib = 6yr survival of 66% INF- Virtually obsolete after advent of tyrosine kinase inhibitors Hydroxyurea For initial stabilization of WBC counts >20 Allopurinol & Antihistamines Symptomatic relief BMT Curative 16
Hairy Cell Leukemia o Mature B-cell leukemia seen in elderly – mainly men o Clinical Presentation Splenomegaly – primary site for neoplastic cells o Diagnosis TRAP & cells w/filamentous hair-like projections
MYELOPROLIFERATIVE NEOPLASMS
Polycythemia Rubra Vera (PRV) o Malignant clonal proliferation of hematopoietic stem cells causing excessive erythrocyte production RBC mass occurs independent of Erythropoietin (EPO) – median survival w/treatment 10-20yrs o Clinical Presentation: Hyperviscosity – headache, dizziness, weakness, visual impairment, dyspnea Bleeding – epistaxis, gingival bleeding, ecchymoses, GI bleeds – due to platelet abnormalities Thrombosis – DVT, PE, thrombophlebitis, risk of stroke/MI – due to viscosity & abnormal PC Erythromelalgia – burning pain of hands & feet w/dusky color – worsened w/heat Pathognomonic microvascular thrombotic complication in PRV & ET Pruritus (40%) Cutaneous mast cell degranulation w/histamine release – facial plethora MC Splenomegaly (70%) hepatomegaly PUD & GI-distress Due to gastric mucosal blood flow alterations from viscosity Gout Hyperuricemia – due to cell turnover o Diagnosis: Diagnostic criteria Must meet 3 major OR any 2 major + 2 minor Major criteria: o RBC mass >25% o O2 saturation >92% – no 2O erythrocytosis from hypoxemia or CO poisoning o Splenomegaly – palpable o Clonal genetic abnormality other than bcr-abl fusion gene o Endogenous erythroid colony formation in vitro Minor criteria: o Thrombocytosis – PC >400 x 109/L o Leukocytosis >12 x 109/L o BM biopsy revealing panmyelosis w/erythroid & megakaryocytic proliferation o EPO Labs EPO, RBC, Hb, Hct, JAK2 mutation o Treatment: Phlebotomy Lowers Hct <45% Myelosuppression Hydroxyurea or Recombinant INF-α (rIFN-α) Symptomatic relief Aspirin, Allopurinol, Antihistamines
Essential Thrombocytosis (ET) o Overproduction of platelets in absence of recognizable stimulus – must R/O 2O thrombocythemia 2O Infection, inflammation, IBD, malignancy, hemorrhage, hemolytic anemia, post splenectomy o Clinical Presentation: Often asymptomatic – headache, dizziness, syncope, thrombosis, bleeding, splenomegaly Erythromelalgia – burning pain of hands & feet w/dusky color – worsened w/heat Caused by platelet activation leading to microvascular thrombosis Complications Risk of spontaneous abortion & risk of transformation to AML in <5% o Diagnosis: Labs PC >600 – also K+ & PO4 due to release of platelet cytoplasmic contents BM Biopsy Enlarged mature megakaryocyte Peripheral Smear Hypogranular, abnormally-shaped platelets JAK2 mutation – acquired Criteria for exclusion of ET: Absent bcr-abl fusion & no evidence of PRV, CML, IMF, MDS or BM fibrosis No reactive thrombocytosis from inflammation, infection, neoplasm or prior splenectomy o Treatment: Hydroxyurea 1st line for thrombocytosis 17
Aspirin Give low-dose if previous H/O thrombotic event or ≥1 cardiovascular risk factors Splenectomy Not recommended due to risk of bleeds & thrombosis
Idiopathic Myelofibrosis (IMF) o Excessive BM fibrosis leading to marrow failure – rare disorder w/average onset at 65yrs o Pathophysiology: Abnormal myeloid precursor produce dysplastic megakaryocytes that secrete FGF Fibroblast growth factors stimulate fibroblasts & stroma to deposit collagen in marrow Fibrosis causes early release of hematopoietic precursors leading to: Leukoerythroblastic blood film – primitive RBC & WBC in blood Migration causing extramedullary hematopoiesis – leads to hepatosplenomegaly o Clinical Presentation: Anemia – severe fatigue & pallor Splenomegaly (90%) & hepatomegaly (70%) portal HTN Weight loss, fever & night sweats – 2O to hypermetabolic state Bone & joint pain – 2O to osteosclerosis & gout o Diagnosis: Peripheral Smear Teardrop RBCs, nucleated RBCs, immature myeloid cells BM Biopsy Diagnostic – fibrosis, atypical megakaryocytes, thickening of bony trabeculae “Dry-tap” in up to 50% w/BM aspirate ALP – 2O to liver involvement & bone disease & LDH – 2O to ineffective hematopoiesis o Treatment: ASCT Potentially curative EPO transfusion For anemia – 30-50% respond to EPO Hydroxyurea For splenomegaly, thrombocytosis, leukocytosis & systemic symptoms Alternatives INF- or Splenectomy Other Thalidomide, JAK2 inhibitors, Etanercept
COMPLICATIONS OF HEMATOLOGIC MALIGNANCIES
Hyperviscosity Syndrome o Blood viscosity resulting from – serum Igs or blood components in hyperproliferative states Waldenstrom’s Macroglobulinemia accounts for 85% of cases o Clinical Presentation: Hypervolemia – CHF, headache, lethargy, dilutional anemia Cerebral blood flow – headache, vertigo, ataxia, stroke Retina show vein engorgement & hemorrhages Bleeding – due to impaired platelet function & absorption of soluble coagulation factors Labs ESR o Treatment Plasmapheresis
Tumour Lysis Syndrome o Metabolic complications resulting from spontaneous or treatment-related breakdown of cancer cells o Labs K+, Uric acid & PO4 – Ca2+ due to binding w/ PO4 o Complications Lethal arrhythmia due to hyperkalemia & ARF due to urate nephropathy o Prevention Allopurinol & aggressive IV hydration w/alkalinization of urine
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