Q&A Medicine>>>>>Hematology and Oncology
Question 2#

A 61-year-old woman with a history of diabetes mellitus, hypertension, and mechanical aortic valve replacement presents with fatigue and periodic palpitations when running. The patient does not endorse shortness of breath or chest pain. Her medications consist of warfarin, metformin, glyburide, lisinopril, and fish oil. On physical examination, she has conjunctival pallor, mechanical click during S2, and a soft systolic flow murmur. Fecal occult blood test is negative. Laboratory results reveal a hemoglobin of 10.1 g/dL, hematocrit of 29%, and a significantly elevated serum LDH. The peripheral blood smear is shown in Figure below.

Which of the following is the underlying cause of this patient’s condition?

a. Autoimmune hemolysis
b. Iron deficiency
c. Traumatic hemolysis
d. Bone marrow infiltration

Correct Answer is C

Comment:

Traumatic hemolysis. The patient in this question is presenting with anemia, elevated LDH, and schistocytes on peripheral blood smear. Increased LDH and schistocytes suggest increased red blood cell (RBC) destruction (i.e., hemolysis) as opposed to decreased RBC production. Traumatic hemolytic anemia is intravascular hemolysis caused by excessive shear or turbulence. Given that this patient has a mechanical aortic valve, her anemia is most consistent with hemolysis secondary to RBC shearing on the valve. Other findings in the setting of hemolytic anemia include decreased haptoglobin and elevated indirect bilirubin. (A) Although autoimmune hemolytic anemia would also demonstrate elevated serum LDH, there will be spherocytes, rather than schistocytes, on peripheral blood smear. Furthermore, direct Coombs test will be positive. (B, D) Iron deficiency and bone marrow infiltration cause decreased RBC production rather than destruction.