Thrombotic microangiopathy in sickle cell disease crisis.

Thrombotic microangiopathy (TMA) in patients with sickle cell disease (SCD) is a rare complication. These patients manifest microangiopathic hemolytic anemia (MAHA) with laboratory evidence of hemolytic anemia, schistocytosis, and thrombocytopenia. This is the first report of the syndrome in a group of these patients. A retrospective chart analysis of 10 consecutively diagnosed patients in SCD crisis who were referred for therapeutic plasma exchange (TPE) after developing MAHA was done. Patients had chest pain, respiratory distress, fever, pulmonary infiltrates, jaundice, and neurological dysfunction with abnormal liver function and coagulation tests. MAHA was diagnosed after a median hospital stay of 5 days. Nine patients recovered completely following TPE with fluid replacement by fresh frozen plasma with or without cryo-poor plasma. Incomplete response to TPE in one case was due to the development of fresh complications. During a median follow-up period of 77 months, there was one recurrent episode and one death in SCD crisis but without evidence of MAHA. TMA is not a very rare complication among Bahraini SCD patients in crisis. Characteristic features of this disorder are acute chest syndrome, organ failure, leuco-erythroblastosis, and a combination of thrombocytopenia, LDH level >1,000 U/l, and schistocytes in blood smears. Management with TPE usually leads to complete recovery with little chance of short-term recurrence. Multiple pathogenetic mechanisms leading to increased von Willebrand factor and its multimers may form the basis of this syndrome.