Thrombotic thrombocytopenic purpura and sickle cell crisis.

Described is a case of acute chest syndrome in a sickle-cell patient (hemoglobin SS) who also developed signs and symptoms of thrombotic thrombocytopenic purpura, including thrombocytopenia and hemolysis (anemia, elevated lactate dehydrogenase, presence of schistocytes, dark-colored plasma, and elevations in nucleated red blood cells). The ADAMTS13 activity level was normal. Discussed are the diagnosis and therapeutic management issues and the challenges of differentiating the vasoocclusive and hemolytic complications of sickling red blood cells from the thrombotic microangiopathy of thrombotic thrombocytopenic purpura.