RELAPSING THROMBOTIC THROMBOCYTOPENIA PURPURA (TTP): A CLINICAL STUDY OF 38 PATIENTS
A dramatic change in the prognosis of TTP has taken place since the introduction of plasma therapy in 1977. However, plasma therapy does not always result in a complete cure since TTP manifestation may reappear. We describe 38 patients who were treated for TTP in 15 hospitals in Israel and New York City since 1977. 37 patients received plasma (transfusions and exchanges) and 30 survived. 12 patients (37%) developed relapsing TTP. Infections, pregnancy and surgery frequently preceded the initial episodes and the relapses. To evaluate the clinical course of relapsing TTP, a scoring system was developed based on 4 parameters: neurological findings, renal function impairment, platelet count and hemoglobin value at presentation. Each parameter was marked on a scale of 0 to 2: 0= no abnormality, 1= moderate impairment, 2= severe impairment. The severity of each episode was the sum of the 4 scores. The cases were divided into 3 groups: Group A= patients who died during 1st episode; Group B= patients who had only one episode; Group C= patients who relapsed. The following are the average severity scores:The differences between Groups A and B; A and C; B and C; and B and the relapses are significant (p<0.005)(Chi-square test). The differences between Group C first episode* and subsequent relapses are not significant (paired t-test). Hence, relapsing TTP was manifested by a milder clinical course, however two relapses were fatal, demonstrating that this is not a benign disorder. Therapy consisted of plasma, plasmapheresis, steroids, platelet-inhibitor drugs and 11 patients underwent splenectomy. Addition of vincristin seemd to shorten the duration of the TTP episode. No differences were observed in the treatment of Group A, B and C patients. However, during relapses, patients received less therapy probably due to their milder clinical course. Splenectomy did not prevent relapses, but prolonged the remission duration. Based on our data, we recommend that the severity score be used in determining the intensity of treatment.