Practice questions answers Anemia I

Practice Question Answers

Anemia I

© Jun Wang, MD, PhD

 

Abbreviations:

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

 

1. C. This case is characterized by anemia associated with trauma induced acute bleeding. It is believed that the initially hematocrit and Hb might be normal due to proportional loss of cells and plasma. However, this initial phase might be very short, as the fluid replacement occurs quickly during blood or plasma loss. The hematopoiesis and RBCs are usually normal, resulting in normal appearing RBCs. The slightly elevated MCV is caused by reticulocytosis, a process commonly induced by anemia. Low Hb and HCT are consistent with anemia. High MCV is seen in megaloblastic anemia, commonly associated with folate and/or VB12 deficiency. Elevated RDW is commonly seen in iron deficiency anemia, thalassemia, sickle cell anemia, etc. TIBC is associated with iron transportation. Low TIBC can be seen in anemia of chronic disease, and higher TIBC is commonly seen in iron deficiency anemia. 

2. C. See discussion of question 1. RBC aggregates may be seen in sickle cell anemia, and cold agglutinin disease, increased plasma protein associated with plasma cell neoplasm, such as multiple myeloma, etc. High indirect bilirubin and low haptoglobin are seen in hemolysis. Target cells can be seen in various hemoglobinopathies, such as thalassemia and HbE, etc.

3. A. The clinical history and PE findings are consistent with anemia associated with acute bleeding. Autoimmune hemolytic anemia is a chronic disorder and usually has history and evidences of hemolysis, such as elevated high bilirubin and low haptoglobin. Hemoglobin abnormalities, such as thalassemia, sickle cell anemia, HbC and HbE, usually present with abnormal RBC morphology. TIBC is high in iron deficiency anemia. Anemia associated with lead poisoning presents with chronic presentations including headache, abdominal pain, neurological abnormalities and RBCs usually have basophilic stippling. VB12 deficiency causes megaloblastic anemia, characterized by macrocytic anemia and neurological abnormalities. These are not seen in this case.

4. C. This patient has typical clinical presentation of malaria that can be confirmed by presence of rings of P. falciparum within RBCs. These protozoa cause hemolysis be direct RBC destruction. So the patient will have lab results of hemolysis, such as elevated high bilirubin and LDH, but low haptoglobin. Reticulocytes will be increased due to normal marrow response to anemia.

5. D. See discussion of question 4. Bone marrow suppression is commonly seen in aplastic anemia. Chronic blood loss caused anemia usually has features of iron deficiency anemia.  Hemoglobin synthesis abnormalities may be associated with thalassemia, sickle cell anemia, HbC and HbE, usually have abnormal RBC morphologies. Nutritional deficiency is associated with iron deficiency anemia and megaloblastic anemia, have smaller or larger RBCs.

6. E. See discussion of question 4. Autoimmune antibodies cause hemolysis in autoimmune hemolytic anemia. Cytoskeletal defects, mechanic shear-force and oxidative stress cause hemolysis in hereditary spherocytosis, microangiopathic hemolysis as seen in hemolytic-uremic syndrome, and thrombotic thrombocytopenic purpura , and G6PD deficiency, respectively. Morphologically, spherocytes are seen in hereditary spherocytosis; schistocytes are seen in microangiopathic hemolysis; bite cells or blister cells are seen in G6PD deficiency. These features are not seen in the current case. Renal failure is associated with anemia of chronic disease, and does not cause hemolysis.  

7. C. This patient has non-specific symptoms. However, pale skin and mucosa are highly indicative of anemia, as confirmed by the low Hb. His MCV is low, meaning smaller RBCs, and his MCHC is low, meaning lower Hb in individual RBCs. So this is a microcytic hypochromic anemia. Macrocytic anemia has larger than normal MCV, and normocytic anemia has normal MCV. Hypochromic anemia has low MCHC, normochromic anemia has normal MCHC, and hyperchromic anemia has higher than normal MCHC.

8. A. This is an old patient and his microcytic hypochromic anemia has high RDW, suggestive of iron deficiency anemia, commonly caused by tumor associated chronic bleeding in this population. Erythroid maturation arrest is seen in pure red cell aplasia, usually presents with normocytic normochromic anemia. Hemoglobin beta gene deletion can be seen in beta halassemia, usually has clinical presentations since birth. Hematopoietic stem cell defect can be seen in aplastic anemia, such as Fanconi anemia, characterized by pancytopenia. Oxidative stress causes hemolysis in G6PD deficiency. Red cell cytoskeleton abnormalities causes hemolysis in hereditary spherocytosis. See discussion of question 6.

9. D. See discussion of question 8. The most common causes of chronic bleeding in older patients include colon cancer in both men and women, and endometrial cancer in women. Bone marrow biopsy is useful in specific diagnosis of many anemia. However, for this patient, the most important management is to rule out potential cancer. Eosin-5-maleimide binding can be used to diagnose hereditary spherocytosis. Enzymatic activity of G6PD can be used to diagnose G6PD deficiency. Hemoglobin electrophoresis is very helpful in diagnosing hemoglobin abnormalities, including thalassemia, sickle cell anemia, HbC and HbE. FA mutation is seen in Fanconi anemia.

10. F. See discussion of question 7.

11. E. This is a patient with normocytic normochromic anemia and a history of chronic disease rheumatoid arthritis, a condition commonly associated with anemia of chronic disease. Bone marrow fibrosis, as seen in myelofibrosis, commonly causes pancytopenia and dysplastic changes of blood cells. Chronic blood loss caused anemia usually has features of iron deficiency anemia, such as reduced MCV and MCHC. Erythroid maturation arrest is seen in pure red cell aplasia, usually presents with normocytic normochromic anemia, with elevated serum iron and transferrin saturation. VB12 deficiency causes megaloblastic anemia, characterized by macrocytic anemia and neurological abnormalities.

12. B. See discussion of question 7.

13. F. See discussion of question 11.

14. F. See discussion of question 7.

15. A. This case is characterized by normocytic normochromic anemia and markedly reduced numbers of WBC and platelets. Frequent infection is associated with leukocytopenia. Easy bruising and PE findings of petechia are associated with thrombocytopenia. These features are consistent with aplastic anemia, and bone marrow biopsy should be performed to confirm the diagnosis and identify causes. Direct Coombs antiglobulin test is used to identify anti-RBC antibodies, commonly seen in immune hemolytic anemia. Hemoglobin electrophoresis is used to identify hemoglobin abnormalities, such as thalassemia, sickle cell anemia, HbC and HbE, usually present with abnormal RBC morphology. Iron studies are used to evaluate the levels of iron, commonly abnormal in iron deficiency anemia, sideroblastic anemia and anemia of chronic disease. Serum folate and VB12 levels are reduced in megaloblastic anemia, characterized by high MCV.

16. B. Hypocellular marrow with marked reduction of all three hematopoietic precursors is consistent with aplastic anemia. Anemia of chronic disease usually affect red cells only. Hemolytic anemia usually has higher reticulocyte count. Iron deficiency anemia and megaloblastic anemia have low and high MCV, respectively. All these three have normal number of WBC and platelets.

17. A. This patient has pancytopenia and low reticulocyte count, consistent with aplastic anemia. See discussion of question 15. Parvovirus B19 infection is more commonly associated with pure red cell aplasia. 

18. A. Beside the presence of aplastic anemia, this patient has short stature and café-au-lait spots. These are suggestive of Fanconi anemia. Chromosomal breakage tests and molecular tests for FANC gene mutations are used to diagnose Fanconi anemia. Flowcytometry for myeloblasts is used to diagnose and classify myeloid neoplasms. Also see discussion of questions 15 and 17.

19. A. Increased chromosomal fragility is seen in Fanconi anemia, associated with mutation of any of these FANC genes, from FANCA to FANCS. Hemoglobin b mutations are seen in various hemoglobin abnormalities, such as beta thalassemia, sickle cell anemia, HbC and HbE. PIGA mutation is seen in paroxysmal nocturnal hemoglobinuria. SPTA1 mutation is seen in hereditary spherocytosis. RPS19 mutation is seen in inherited pure red cell aplasia.

20. B. Increased chromosomal fragility is seen in Fanconi anemia. Anemia of chronic disease tends to be normocytic anemia, and should have history of associated chronic disease and reduced TIBC. Hemolytic anemia usually has higher reticulocyte count. Paroxysmal nocturnal hemoglobinuria has typical presentations of dark urine starting at night. Pure red cell aplasia usually presents with normocytic normochromic anemia, with elevated serum iron and transferrin saturation. These three usually affect red cells only. 

21. A. See discussion of questions 15 and 18.

22. E. This is a case of sudden onset of normocytic anemia with marked reticulocytopenia. Her WBC and platelet counts are normal. Marrow biopsy reveals isolated erythroid hypoplasia. These features are consistent with transient pure red cell aplasia, that might be associated with parvovirus B19 infection. Othe viral infections rarely associated with pure red cell aplasia.

23. E.  See discussion of question 22. AML and MDS have abnormal WBC count and morphology. Fanconi anemia has pancytopenia and birth defects. Iron deficiency anemia has reduced MCV and MCHC and abnormal iron test results.

 

 

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