Postoperative thrombotic thrombocytopenic purpura after open heart operations.

BACKGROUND: Postoperative thrombotic thrombocytopenic purpura (pTTP) after cardiovascular operations has an alarmingly high mortality rate if untreated. Five patients after coronary artery bypass graft (CABG) procedure were diagnosed with pTTP when they were observed to have a persistent thrombocytopenia associated with symptoms of fever, renal insufficiency, thromboembolic events, or altered mental status in conjunction with a microangiopathic hemolytic anemia (MAHA). A guideline for early diagnosis, followed by timely treatment in these cases, is reviewed. METHODS: A retrospective record review of postoperative patients with thrombocytopenia identified 5 patients that met the criteria for pTTP from 2004 to 2008. We examined these 5 cardiovascular surgical patients in terms of clinical presentation, laboratory data, and outcomes. RESULTS: All patients had the combination of an unexplained thrombocytopenia (platelets < 50,000 mm(3)) in conjunction with a MAHA as determined by the presence of schistocytes. Symptoms of neurologic dysfunction and renal insufficiency developed in all patients. Thromboembolic events were noted in 1 patient. All patients underwent plasmapheresis. In 3 patients, response time to clinical recovery and normalization of hematologic laboratory values after plasmapheresis was 3, 4, and 8 days. Two patients did not recover and died. One patient had a clinical and laboratory recovery after 19 days of plasmapheresis; however, after 11 days, thrombocytopenia with MAHA developed and he died on day 53 from complications related to the operation. CONCLUSIONS: Postoperative TTP should be recognized as a possible pathophysiologic mechanism for unexplained postoperative thrombocytopenia and treatment should be initiated once the diagnosis is established.

Factor XIII deficiency mistaken for battered child syndrome: case of "correct" test ordering negated by a commonly accepted qualitative test with limited negative predictive value.

We report herein a case of Factor XIII deficiency that remained undiagnosed until 2 years of age. Part of the delay in diagnosis was a consequence of testing that was performed on a blood sample obtained after plasma transfusion therapy for a life-threatening bleeding episode. Due to insufficient family follow-up after discharge from the hospital, the diagnosis was delayed 1 year until the child was rehospitalized and a pre-transfusion plasma sample was tested. The commonly accepted approach of using only a qualitative test for the diagnosis of factor XIII deficiency is challenged by this case report.