Acquired thrombotic thrombocytopenic purpura in children: A single institution experience

Objective: To describe the clinical features, treatment and prognosis of acquired thrombotic thrombocytopenic purpura (TTP) in children based on a single institution experience. Methods: This study is a retrospective review of all 12 children with TTP seen at New York Medical College- Westchester Medical Center during a period of 15 y from 1993 to 2008. Results: There were 7 females and 5 males with acquired TTP, with a median age of 13 (range, 6-17); and no cases of congenital TTP. The classic pentad of TTP (microangiopathic hemolytic anemia, thrombocytopenia, neurologic symptoms, renal dysfunction and fever) was seen in only three patients. Nine had renal involvement; eight had neurologic symptoms; and four had fever. All 12 patients had thrombocytopenia, anemia, and elevated LDH. Nine had idiopathic TTP. Three patients had one of the following underlying disorders: systemic lupus erythematosus, mixed connective tissue disorder, and aplastic anemia (post-bone marrow transplant on cyclosporine). ADAMTS13 level was decreased in 7 of 8 patients studied. Eight of 10 patients achieved remission with plasmapheresis alone. Two needed additional treatment before achieving remission. Two had one or more relapses, requiring immunosupressive treatment with vincrisine, prednisone, or rituximab. The patient with aplastic anemia died of pulmonary hypertension 5 y after bone marrow transplantation. All other 11 patients are alive and free of TTP for a median follow-up of 12 mo (range, 3-72 mo). Conclusions: Acquired pediatric TTP responds well to plasmapheresis. However, many patients do require additional treatment because of refractoriness to plasmapheresis or relapse. The clinical features, response to treatment, and relapse rate of pediatric TTP appear similar to those of adult TTP.