Thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS): Treatment outcome, relapses, prognostic factors. A single-center experience of 48 cases

The thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS) is a rare disorder characterized by microangiopathic hemolysis and thrombo cytopenia. We have undertaken a retrospective analysis of the clinical char acteristics, treatment outcome, and prognosis of 48 patients diagnosed and treated in our institution during a 13-year period. Among our patients 22 ( 46%) had fever, 35 (73%) neurological abnormalities, and 22 (46%) renal imp airment at presentation of the syndrome. All patients were treated with a m ultimodality regimen including plasma exchange, steroids, antiplatelet agen ts, and IgG infusion. Of the 48 patients, 41 achieved complete remission, t wo had a partial response, and five had no response and died of progressive disease. Within a median follow-up period of 40 months, ten of the 41 pati ents who had achieved remission relapsed, most of them within the first 2 y ears, and nine of these responded promptly to plasma exchange therapy. Eigh t deaths were observed, seven of refractory disease and one in fourth relap se. The analysis of prognostic factors revealed advanced age and severe ren al impairment (creatinine levels above 2 mg%) as the only parameters associ ated with treatment failure and poor outcome. However, none of the pretreat ment characteristics proved to be of prognostic value regarding the probabi lity of relapse. In conclusion, TTP/HUS represent a syndrome of variable cl inical expression and aggressiveness. The use of a multimodality regimen in our series produced a high response rate. Nevertheless, the early identifi cation, based on clinical characteristics, of poor-prognosis cases that pro bably need more or alternative forms of treatment is an issue that remains to be elucidated in prospective trials.