Sudden Onset of Severe Anemia in a Patient with Cystic Fibrosis

[摘要] A 26-year-old woman with end-stage lung disease secondary to cystic fibrosis, cirrhosis secondary to hepatitis C, and insulin-dependent diabetes mellitus presented with acute pneumonia. She was treated with intravenous piperacillin/tazobactam and tobramycin. Other medications included dexamethasone, bumetanide, pantoprazole, dornase, and insulin. At admission, the patient's hematocrit was 30.8% (Table 1). On day 8 of hospitalization, she developed severe anemia with a hematocrit of 11.5%. Her blood type was group A, Rh D-positive, and the results of her antibody screen (performed in solid-phase, low-ionic-strength solution), which had previously been positive for only anti-E antibody, were now positive with a panreactive pattern. The result of the direct antiglobulin test (DAT)3 was 2+ (moderately positive) for IgG, and the eluate was nonreactive. Six units of red blood cells (RBCs) were requested for transfusion. Her plasma was weakly to moderately cross-match incompatible with all group A–positive, E antigen–negative units tested. Given the severity of her anemia, 6 of these units were emergently released for transfusion to stabilize the patient while the investigation of her anemia and the new serologic findings continued.View this table:Table 1. Laboratory results for day 1 and day 8 of hospitalization.Only 2 mechanisms were likely responsible for such an abrupt and severe decrease in the hematocrit: bleeding and hemolysis. Bleeding was initially suspected; however, no source of hemorrhage was found. On the other hand, laboratory findings revealed high lactate dehydrogenase (LDH) activity, hemoglobinuria, and unconjugated hyperbilirubinemia, all of which were consistent with hemolysis. The positive DAT result indicated an immune-mediated etiology. The panreactive pattern of the antibody panel results suggested warm autoantibodies, but the nonreactive eluate eliminated this possibility because panreactivity should also be observed in the eluate. The anti-E antibody first detected at admission indicated that the patient had received a transfusion or had become pregnant at some point in her life. There was no history of recent transfusion, however, and …

[学科分类] 过敏症与临床免疫学