A 50-year-old White woman presents with a 3-week history of tiredness and pallor. A family member has noted some yellowness of her eyes, but she denies darkening of the urine. Physical examination reveals only slight jaundice. Laboratory data include hemoglobin of 9 g/dL, reticulocyte count of 8%, a bilirubin in the serum of 2 mg/dL (indirect reacting), and some microspherocytes on peripheral smear. The direct antiglobulin test (Coombs’) is positive. Which of the following is the most likely cause for her anemia?
(A) blood loss externally
(B) decreased red cell production
© ineffective erythropoiesis
(D) intravascular hemolysis
(E) extravascular hemolysis
solution:
(E) This patient has autoimmune hemolysis and the red cell destruction is extravascular, usually occurring in the liver, spleen, or other reticuloendothelial sites. It liberates unconjugated bilirubin causing jaundice. Intrinsic
causes of hemolytic anemia are usually inherited, and are a result of abnormalities of membranes, red cell enzymes, globins, or heme. Extrinsic hemolysis is a result of mechanical forces, chemicals or microorganisms, antibodies, or sequestration in the monocyte-macrophage system