Practice questions answers Anemia IV

Practice questions answers

Anemia IV

© 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. E. This is a case of anemia with history of bleeding. Her lab results show microcytic anemia with elevated RDW. Peripheral blood smear reveals enlarged central pallor area, consistent with hypochromic anemia. One of the most cause in such a setting is iron deficiency anemia. Bone marrow biopsy is useful in specific diagnosis of many anemia, especially hematopoietic stem cell abnormalities, such as aplastic anemia and myeloid neoplasms. Direct antiglobulin test can identify antibodies/complement bound directly to RBCs, usually positive for immune hemolytic anemia. Hemoglobin analysis by electrophoresis of HPLC is very helpful in diagnosing hemoglobin abnormalities, including thalassemia, sickle cell anemia, HbC and HbE. Eosin-5-maleimide binding assay and osmotic fragility test is used to diagnose hereditary spherocytosis.

2. D. Her iron tests reveal low ferritin, an indicator of iron storage, and low serum iron levels. These are consistent with iron deficiency anemia, that will have elevated TIBC. Reduce haptoglobin and elevated bilirubin are indicating for hemolysis, when the patients have jaundice, schistocytes or spherocytes. Hepcidin usually suppress iron metabolism and are elevated in cases of iron overloading, or chronic inflammation. Its level is reduced in iron deficiency anemia, when transferrin saturation is reduced.

3. E. The clinical presence and lab iron studies are consistent with the diagnosis of iron deficiency anemia, that bone marrow iron storage is commonly reduced or depleted. Erythroid precursor with iron particles surrounding nuclei, or ring sideroblasts, are seen in sideroblastic anemia. Hypocellular bone marrow with focal fibrosis is commonly associated with aplastic anemia. Isolated erythroid hyperplasia with nuclear atypia is a sign of myeloid neoplasms. Myeloid precursors with hypersegmented nuclei are seen in megaloblastic anemia, commonly associated with folate and/or VB12 deficiency.

4. E. Reduced heme synthesis is seen in iron deficiency anemia, since iron is a part of heme. Acute hemorrhage usually cause normocytic normochromic anemia. Delayed division of hematopoietic precursors is seen in megaloblastic anemia, commonly associated with folate and/or VB12 deficiency. Erythroid stem cell defects is seen in various types of aplastic anemia. Red cell membrane instability is seen in hereditary spherocytosis.

5. C. Chronic bleeding is a common cause of iron deficiency anemia. This patient does have history of heavy bleeding. Other options do not have supportive clinical history.

6. B. See discussion of question 2. Alpha thalassemia carrier usually has normal Hb levels. Lead associated anemia usually neurological presentations, RBCs with basophilic stippling, and normal to elevated ferritin. Megaloblastic anemia has higher MCV. Sickle cell anemia has sickle cells. 

7. D. Iron supplementation is needed for patients with iron deficiency anemia. Bone marrow molecular test for clonal proliferation is used for myeloid neoplasms. Colonoscopy exam and endometrial biopsy are useful to rule out underlying causes of iron deficiency anemia in older patients. Vitamin B12 supplementation is used for megaloblastic anemia associated with VB12 deficiency.

8. B. See discussion of questions 1, 6 and 7. Renal function panel is used to diagnose renal failure, that may be associated with anemia of chronic disease, a normocytic anemia. Serum lead test is used to confirm lead poisoning, a cause of microcytic anemia.

9. A. This is a case of microcytic anemia with high serum ferritin, commonly seen in sideroblastic anemia. Bone marrow biopsy with iron studies may estimate the presence of ring sideroblasts, and evaluate the possibility of myeloid neoplasms. Also see discussion of questions 1, 7 and 8. 

10. A. The image reveals a few ring sideroblasts, consistent with sideroblastic anemia. The cause of sideroblastic anemia include excessive alcohol use, lead poisoning,  myeloid neoplasms, etc. This patient has history of heavy alcohol use, and is most likely to be the cause of his anemia. Hemoglobin abnormalities, including thalassemia, sickle cell anemia, HbC and HbE, have red cell changes, such as sickle cell, rhomboidal crystals, or target cells. Iron deficiency anemia has low serum ferritin and transferrin saturation. Vitamin B12 deficiency is associated with megaloblastic anemia.

11. D. The cause of abnormal intracellular iron deposit in sideroblastic anemia is defects in iron utilization during heme synthesis. Other conditions will neither cause iron overload in erythroid, nor seen in sideroblastic anemia.

12. E. See discussion of questions 9 and 10.

13. E. This case is characterized by macrocytic anemia with hypersegmented neutrophils, consistent with megaloblastic anemia, commonly associated with folate and/or VB12 deficiency. Also see discussion of questions 1 and 8. 

14. Megaloblastic anemia is commonly associated with folate and/or VB12 deficiency and usually has elevated homocysteine. Hepcidin level is associated with iron metabolism, but not VB12 or folate deficiencies. Indirect bilirubin is increased when there is hemolysis. Iron level is high in sideroblastic anemia. Lead level is elevated in lead poisoning, usually has microcytic anemia. TIBC is elevated in iron deficiency anemia but not megaloblastic anemia.

15. A. 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. Inhibition of δ-aminolevulinate dehydratase is seen in lead poisoning, usually has microcytic anemia. Iron deficiency causes iron deficiency anemia, a microcytic anemia. Red cell membrane instability cause spherocytic appearance, characterized by loss of central pallor area, as seen in hereditary spherocytosis.

16. A. Absorption of VB12 needs intrinsic factor produced by parietal cells. This patient has a history of autoimmune gastritis, when the parietal cells are destroyed by autoantibodies. The patient does not have history for other options.

17. D. See discussion of questions 13 and 15. Pernicious anemia is a type of megaloblastic anemia due to VB12 deficiency, associated with autoimmune gastritis.  Hereditary spherocytosis has RBCs with spherocytic appearance, characterized by loss of central pallor area.

 

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