Thrombotic Thrombocytopenic Purpura: An Uncommon but Fatal Complication in Patients with Systemic Lupus Erythematosus

Objective: To investigate the clinical manifestations, renal pathological features, outcome and risk factors for mortality of thrombotic thrombocytopenic purpura (TTP) in systemic lupus erythematosus (SLE) patients.Methods: Twelve SLE patients with TTP were enrolled retrospectively from January 2004 to December 2008 in Taichung Veterans General Hospital. Four of them received renal biopsy for acute renal failure. The clinical-pathological data and prognosis were reviewed.Results: The incidence of TTP in SLE patients in our hospital was 4.2 cases per thousand per year. All patients had evidence of microangiopathic hemolytic anemia (MAHA), thrombocytopenia, and acute renal failure (only one exception). Four patients received renal biopsy which showed diffuse proliferative lupus nephritis and thrombotic microangiopathy (TMA) features. All patients received plasmapheresis, high dose steroids and cyclophosphamide therapy (only two exception). Six patients had remission of lupus nephritis. The in-hospital mortality rate was 33.3%. Compared with the survivors, the deceased had signifi cant lower levels of the complement (C3), higher Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores and a higher infection rate.Conclusion: In SLE patients, TTP can be fatal, especially in those with superimposed infection or high disease activity of lupus. Thus clinicians should be alert to the TTP manifestations, including MAHA, thrombocytopenia, acute renal failure, fever or neurological abnormalities.