Human granulocytic ehrlichiosis presenting with acute renal failure and mimicking thrombotic thrombocytopenic purpura

We present the case of an elderly female patient presenting with recurrent acute renal failure, fever, altered mental status, abdominal pain, thrombocytopenia and a small number of fragmented red cells on peripheral smear mimicking recurrent thrombotic thrombocytopenic purpura (TTP). Eventually, however, she was diagnosed to have human granulocytic ehrlichiosis (HGE), and after treatment for HGE her clinical and laboratory abnormalities resolved. Ehrlichiosis mimicking TTP, diagnosed at postmortem examination, has been described in a single prior case. As illustrated in this case, there are potential difficulties in diagnosing HGE after plasma exchange, blood transfusion and immunosuppressive therapy. Ehrlichiosis, a potentially curable disease, should be considered in the differential diagnosis of thrombotic microangiopathic disorders.