PLASMA-EXCHANGE FOR TREATMENT OF THROMBOTIC THROMBOCYTOPENIC PURPURA IN CRITICALLY ILL PATIENTS

Objective: Description of diagnostic procedures, treatment modalities and intensive care management of patients with thrombotic thrombocytop enic purpura (TTP). Design: Descriptive study. Setting: Internal medic ine Intensive Care Unit (University Hospital of Vienna). Patients: Six patients (two after allogeneic bone marrow transplantation), treated for 12 episodes of TTP. Interventions: Treatment with plasma exchange (fresh frozen plasma, 50-80 ml/kg per day), prednisone (0.75 mg/kg b.i .d.) and, in some cases, vincristine. Supportive therapy as needed. Me asurements and Results: Patients were admitted to the ICU because of n eurological symptoms with acute on set (42% mild, 58% severe), hemolys is and thrombocytopenia. Additional symptoms were fever (50%), bleedin g tendency (50%), acute renal failure (42%) and metabolic derangement (8%). Initial laboratory values showed thrombocytopenia (median 17 G/l ), hemolysis (median hemoglobin 10.0 g/dl, lactate dehydrogenase 635 U /l, reticulocyte count 175 G/l) with red cell fragmentation. Coagulati on tests were normal. Respiratory assist was needed in six episodes (s evere seizures, cardiopulmonary resuscitation). In patients without pr eexisting hematological abnormality the platelet counts exceeded 100 G /l after 3-8 cycles of plasma exchange. In patients after bone marrow transplantation, the platelet counts never exceeded 40 G/l, but the la ctate dehydrogenase levels dropped significantly. The neurological sym ptoms disappeared in all patients and renal function normalized. One p atient died before the initiation of therapy. Three patients relapsed 1-3 times between 2 weeks and 5 months after the last episode. The rel apses were associated with symptoms similar to the first episode and r esponded promptly to plasma therapy. Conclusions: TTP is a rare, but l ife-threatening disorder. It needs immediate diagnosis and has a good prognosis after adequate treatment with plasma exchange.