Haemolytic-uraemic syndrome and thrombotic-thrombocytopenic purpura in adults: clinical findings and prognostic factors for death and end-stage renal disease.

BACKGROUND: Left untreated, haemolytic-uraemic syndrome (HUS) and thrombotic-thrombocytopenic purpura (TTP) in adults have a poor prognosis with mortality rates reaching 90%. Patients who survive often develop end-stage renal disease. Because of similarities in clinical and morphological findings, both diseases are considered as one entity referred to as HUS-TTP syndrome.
METHODS: From 1974 to January 1995, 45 adult patients received treatment for HUS-TTP at our clinic. By stepwise logistic regression analyses, we examined how known risk factors and plasma exchange with fresh-frozen plasma (PE) influenced mortality and end-stage renal disease.
RESULTS: Three of 45 patients died (7%). Though we were not able to find significant predictors of mortality, low haemoglobin levels (5.93 +/- 0.32 vs 9.10 +/- 2.16 g/dl) and high leukocyte counts on admission (15.830 +/- 3.690 vs 11.150 +/- 4.580 microliters-1) appeared to indicate an unfavourable outcome. Regarding the development of end-stage renal disease, PE proved to be the only favourable indicator (P = 0.0001). PE was performed in 30 patients 3-20 times (9.2 +/- 4.8, mean +/- SD). Of 28 surviving patients treated with PE, only four developed end-stage renal disease, whereas dialysis was necessary in 11 of 14 patients not treated with PE. Application of PE led to an 81.8% reduction of the relative risk of developing end-stage renal disease. An additional prognostic influence of other potential risk factors such as age, sex, platelet count on admission, lactate dehydrogenase serum levels, serum creatinine, blood pressure, prodromal disease, and renal histology was not found.
CONCLUSION: This retrospective clinical study confirms the therapeutic value of plasma exchange with fresh-frozen plasma to maintain renal function in patients with HUS-TTP.