PANRE Hematology 2 — Questions and Answers
Question 1: A 55-year-old male presents with plethora, headache, and pruritus after bathing. Hgb is 19.4 g/dL, Hct 58%, WBC 13,000/μL, platelets 520,000/μL. JAK2 V617F mutation is positive. What is the most likely diagnosis?
- Secondary polycythemia
- Polycythemia vera (Correct answer)
- Essential thrombocythemia
- Chronic myelogenous leukemia
Correct answer: Polycythemia vera
Polycythemia vera is a myeloproliferative neoplasm characterized by elevated red cell mass, JAK2 V617F mutation, and aquagenic pruritus, with associated thrombocytosis and leukocytosis.
Question 2: A 24-year-old African American male develops hemolytic anemia and hemoglobinuria after being prescribed dapsone for dermatitis herpetiformis. Peripheral smear shows Heinz bodies. What is the underlying defect?
- Pyruvate kinase deficiency
- Glucose-6-phosphate dehydrogenase (G6PD) deficiency (Correct answer)
- Hereditary spherocytosis
- Sickle cell trait
Correct answer: Glucose-6-phosphate dehydrogenase (G6PD) deficiency
G6PD deficiency causes oxidative hemolysis when triggered by oxidant drugs (dapsone, primaquine), infections, or fava beans, resulting in Heinz body formation and intravascular hemolysis.
Question 3: A 6-year-old boy has recurrent hemarthroses and prolonged bleeding after minor trauma. PTT is 68 seconds (normal <35), PT is normal, platelet count is normal, bleeding time is normal. Factor VIII activity is 2%. What is the diagnosis?
- Hemophilia B
- Hemophilia A (Correct answer)
- Von Willebrand disease type 3
- Factor VII deficiency
Correct answer: Hemophilia A
Hemophilia A is caused by factor VIII deficiency, presenting with hemarthroses and deep muscle bleeds, prolonged PTT with normal PT, and very low factor VIII activity levels.
Question 4: A 30-year-old presents with pancytopenia: Hgb 7.1, WBC 1,800, platelets 28,000. Bone marrow biopsy shows a hypocellular marrow with >70% fat cells. No splenomegaly. What is the most appropriate treatment for severe aplastic anemia in a patient with a matched sibling donor?
- Immunosuppression with antithymocyte globulin and cyclosporine
- Allogeneic hematopoietic stem cell transplantation (Correct answer)
- G-CSF therapy alone
- Corticosteroids and erythropoietin
Correct answer: Allogeneic hematopoietic stem cell transplantation
Allogeneic hematopoietic stem cell transplantation from a matched sibling donor is the curative treatment of choice for severe aplastic anemia in young patients.
Question 5: A patient has a positive direct Coombs test, elevated indirect bilirubin, low haptoglobin, and reticulocytosis. Peripheral smear shows spherocytes. Splenomegaly is present. What condition is most consistent with these findings?
- Hereditary spherocytosis
- Autoimmune hemolytic anemia (Correct answer)
- Microangiopathic hemolytic anemia
- Paroxysmal nocturnal hemoglobinuria
Correct answer: Autoimmune hemolytic anemia
Autoimmune hemolytic anemia (AIHA) is confirmed by a positive direct Coombs (DAT) test, which detects IgG or complement on RBC surfaces, causing extravascular hemolysis with spherocyte formation.
Question 6: A post-surgical ICU patient develops DIC. Labs show: PT prolonged, PTT prolonged, fibrinogen 80 mg/dL, D-dimer markedly elevated, platelet count 42,000/μL, and schistocytes on smear. What is the most critical initial management step?
- Administer heparin to prevent further clotting
- Treat the underlying cause and replace clotting factors with FFP and cryoprecipitate (Correct answer)
- Platelet transfusion alone
- Administer tranexamic acid immediately
Correct answer: Treat the underlying cause and replace clotting factors with FFP and cryoprecipitate
DIC treatment centers on addressing the precipitating cause while supporting coagulation with FFP (for clotting factors) and cryoprecipitate (for fibrinogen) and platelets as needed.
Question 7: A patient receiving unfractionated heparin for 8 days develops a platelet count drop from 230,000 to 65,000/μL and a new arterial thrombosis. What is the most appropriate next step?
- Increase the heparin dose to achieve therapeutic anticoagulation
- Discontinue heparin and start a direct thrombin inhibitor such as argatroban (Correct answer)
- Switch to low-molecular-weight heparin
- Administer platelet transfusion
Correct answer: Discontinue heparin and start a direct thrombin inhibitor such as argatroban
Heparin-induced thrombocytopenia (HIT) with thrombosis requires immediate cessation of all heparin and initiation of a non-heparin anticoagulant like argatroban; platelet transfusion is contraindicated.
PANRE Hematology 2
A 55-year-old male presents with plethora, headache, and pruritus after bathing.
Hgb is 19.4 g/dL, Hct 58%, WBC 13,000/μL, platelets 520,000/μL.
JAK2 V617F mutation is positive.
What is the most likely diagnosis?