Internal Medicine Exam Hematology 1 — Questions and Answers
Question 1: A 45-year-old woman presents with fatigue and pallor. Labs show Hgb 8.2 g/dL, MCV 72 fL, and low serum ferritin. What is the most likely diagnosis?
- Vitamin B12 deficiency anemia
- Iron deficiency anemia (Correct answer)
- Anemia of chronic disease
- Thalassemia trait
Correct answer: Iron deficiency anemia
Iron deficiency anemia classically presents with microcytic anemia (low MCV) and low serum ferritin, which is the most specific marker of depleted iron stores.
Question 2: Which lab finding best distinguishes iron deficiency anemia from anemia of chronic disease?
- Low hemoglobin
- Low serum ferritin (Correct answer)
- Elevated serum ferritin with low TIBC
- Elevated reticulocyte count
Correct answer: Low serum ferritin
A low serum ferritin is highly specific for iron deficiency anemia; in anemia of chronic disease, ferritin is normal or elevated because it is an acute-phase reactant.
Question 3: A 65-year-old man presents with Hgb 7.5 g/dL, MCV 110 fL, and hypersegmented neutrophils on peripheral smear. What is the most appropriate next step?
- Bone marrow biopsy
- Serum B12 and folate levels (Correct answer)
- Iron studies
- Peripheral blood smear for malaria
Correct answer: Serum B12 and folate levels
Macrocytic anemia with hypersegmented neutrophils strongly suggests megaloblastic anemia due to B12 or folate deficiency, which should be confirmed with serum levels.
Question 4: Pernicious anemia results from which underlying mechanism?
- Dietary iron deficiency
- Autoimmune destruction of parietal cells leading to intrinsic factor deficiency (Correct answer)
- Folate malabsorption in the terminal ileum
- Chronic gastrointestinal blood loss
Correct answer: Autoimmune destruction of parietal cells leading to intrinsic factor deficiency
Pernicious anemia is caused by autoimmune destruction of gastric parietal cells, leading to loss of intrinsic factor, which is required for terminal ileum absorption of vitamin B12.
Question 5: A patient with sickle cell disease presents with an acute vaso-occlusive pain crisis. What is the MOST important initial management step?
- Exchange transfusion
- IV fluids and adequate analgesia (Correct answer)
- Initiation of hydroxyurea
- Urgent bone marrow transplant evaluation
Correct answer: IV fluids and adequate analgesia
Acute vaso-occlusive pain crisis is managed with IV hydration to improve blood flow and adequate analgesia (NSAIDs, opioids) to control pain.
Question 6: Hereditary spherocytosis is caused by a defect in which cellular component?
- Spectrin or ankyrin proteins in the RBC membrane (Correct answer)
- Hemoglobin beta-globin chains
- Pyruvate kinase enzyme
- Glucose-6-phosphate dehydrogenase
Correct answer: Spectrin or ankyrin proteins in the RBC membrane
Hereditary spherocytosis results from mutations in RBC membrane proteins (spectrin, ankyrin, band 3), leading to loss of membrane surface area, spherocyte formation, and hemolysis in the spleen.
Question 7: A patient with G6PD deficiency develops acute hemolytic anemia after starting primaquine. What is the underlying mechanism?
- Immune-mediated destruction of RBCs via antibodies
- Oxidative stress causing Heinz body formation and hemolysis (Correct answer)
- Mechanical destruction of RBCs in small vessels
- Complement-mediated intravascular lysis
Correct answer: Oxidative stress causing Heinz body formation and hemolysis
G6PD deficiency impairs the pentose phosphate pathway, leaving RBCs unable to neutralize oxidative stress; oxidant drugs cause Heinz body formation and subsequent hemolysis.
Internal Medicine Exam Hematology 1
A 45-year-old woman presents with fatigue and pallor.
Labs show Hgb 8.2 g/dL, MCV 72 fL, and low serum ferritin.
What is the most likely diagnosis?