Practice Question Answers Anemia V

Practice Question Answers

Anemia V

© Jun Wang, MD, PhD

 

Abbreviations:

Hb: hemoglobin	HCT: hematocrit
MCV: Mean Corpuscular Volume	MCH: Mean Corpuscular Hemoglobin
RDW: Red Cell Distribution Width	TIBC: total iron binding capacity

 

1. D. This case is characterized by microcytic anemia. The history of living in an old house is suspicious for lead exposure, further supported by PE finding of lead line in gingiva. Peripheral blood smear reveals small red cells with basophilic stippling, highly suggestive of lead poisoning. Bone marrow biopsy is useful in specific diagnosis of many anemia, especially hematopoietic stem cell abnormalities, such as aplastic anemia and myeloid neoplasms. Eosin-5-maleimide binding assay and osmotic fragility test is used to diagnose hereditary spherocytosis. Hemoglobin analysis by electrophoresis of HPLC is very helpful in diagnosing hemoglobin abnormalities, including thalassemia, sickle cell anemia, HbC and HbE. Serum folate and VB12 tests are useful in confirm folate or VB12 deficiencies, common causes for megaloblastic anemia. Iron studies are useful in diagnosing iron metabolism abnormalities, such as iron deficiency anemia, sideroblastic anemia and anemia of chronic disease.

2. B. Elevated blood lead levels and microcytic anemia are consistent with anemia associated with lead poisoning. Lead inhibits several enzymes during heme synthesis, most commonly delta-aminolevulinate dehydratase, ferrochelatase and coproporphyrin oxidase. Erythroid hyperplasia and hypersegmented myeloid precursors is seen in megaloblastic anemia. Hypocellular marrow largely replaced by adipose tissue is commonly seen in aplastic anemia. Isolated erythroid aplasia is seen in pure red cell aplasia. Myelofibrosis is seen in some types of myeloid neoplasms, such as myelofibrosis.

3. C. See discussion of question 2. Decreased erythropoietin production is seen in chronic renal failure, and can be associated with anemia of chronic disease. Erythroid maturation arrest, if isolated, can be seen in pure red cell aplasia. Increased hemolysis can be seen in hemoglobin abnormalities, including thalassemia, sickle cell anemia, HbC and HbE, or structural defects, such as hereditary spherocytosis, or enzymatic or immune abnormalities. Hemolytic anemia has jaundice and elevated LDH and bilirubin. Red cell structural protein defects is seen in hereditary spherocytosis.

4. E. see discussion of questions 2 and 3.  Deletion of 3 or 4 a globin gene is seen in Hb H and Hb Bart disease. Deletion of 1 or 2 b globin gene is seen in beta thalassemia. Erythroid stem cell damage can be seen in pure red cell aplasia or paroxysmal nocturnal hemoglobinuria.

5. C. See discussion of questions 1 and 2. Alpha thalassemia trait may presents with mild microcytic hypochromic anemia with higher RBC count. Iron deficiency anemia is also microcytic hypochromic anemia with reduced serum iron, ferritin, transferrin saturation and elevated TIBC. Megaloblastic anemia is macrocytic anemia. Sickle cell anemia has sickle cells in peripheral blood. None of these has basophilic stippling in RBCs. 

6. D. This case is characterized by microcytic anemia in a patient with history of chronic heavy menstrual bleeding. Peripheral blood smear reveals microcytic hypochrmic anemia with great variation in RBC sizes. Iron deficiency anemia is highly suspicious in this setting and she most likely has low transferrin saturation. Low transferrin saturation will suppress production of hepcidin in liver. Erythropoietin will indeed increase in patients with anemia, except those with chronic renal failure. Red cell distribution width and TIBC are elevated in iron deficiency anemia. Indirect bilirubin is an indicator of hemolysis. Its level is usually not directly relevant to iron metabolism.

7. E. Serum level of hepcidin is affected by various factors. Higher levels of hepcidin are commonly associated with chronic inflammation or higher transferrin saturation. It is reduced when there are elevated erythropoietin, low transferrin saturation, or hypoxia.

8. C. See discussion of questions 5 and 6.

9. E. This case is characterized by macrocytic anemia with hypersegmented neutrophils, consistent with megaloblastic anemia, commonly associated with folate and/or VB12 deficiency. Since this patient does not have neurological abnormalities, folate deficiency is more likely. Also see discussion of question 1.

10. B. Serum test confirmed folate deficiency while VB12 is in normal range. Megaloblastic anemia caused by either folate or VB12 deficiency has elevated homocysteine. However, methylmalonic acid will increased in VB12 deficiency, but usually is normal in folate deficiency.

11. A. Folate deficiency is commonly caused by inadequate dietary intake of green leafy vegetables or over-cooked vegetables, chronic alcohol use, GI disorders, certain medications and increased requirements during pregnancy or chronic hemolysis. This patient has a history of chronic alcohol consumption, but no history of GI disorders, etc. It is not sure whether cigarette smoking will reduce folate absorption.

12. B. Folate and VB12 are needed for DNA synthesis. Deficiency of both or either will cause DNA synthesis defect and delayed cell division in megaloblastic anemia, characterized by macrocytic anemia with hypersegmented granulocytes. Hemoglobin abnormalities, including thalassemia, sickle cell anemia, HbC and HbE, have red cell changes, such as sickle cell, rhomboidal crystals, or target cells, but not hypersegmented granulocytes. Erythroid stem cell defect can be seen in pure red cell aplasia. Precipitation of hemoglobin is commonly seen in hemoglobin abnormalities, especially sickle cell anemia and HbC. Red cell membrane instability is seen in hereditary spherocytosis.

13. E. See discussion of questions 9 and 10. Anemia of chronic disease is usually normocytic. Hereditary spherocytosis is characterized by presence of spherocytes and evidence of hemolysis. Iron deficiency anemia is microcytic hypochromic anemia with reduced serum iron, ferritin, transferrin saturation and elevated TIBC. Anemia associated with lead poisoning is microcytic anemia with basophilic stippling in RBCs.

14. B. This case is characterized by normocytic anemia in a patient with history of chronic inflammations, including chronic kidney disease, Crohn disease and diabetes. All these are supportive of anemia of chronic disease, especially when iron studies reveals no evidence of iron deficiency. Chronic inflammation often results in elevated levels of hepcidin. Erythropoietin tends to be lower in patients with chronic kidney disease. Indirect bilirubin is an indicator of hemolysis. Both serum iron and TIBC tend to be lower in anemia of chronic disease, even though ferritin levels may be elevated.

15. E. See discussion of questions 12 and 14.

16. A. See discussion of questions 13 and 14. Megaloblastic anemia is macrocytic anemia.

 

 

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