Successful treatment with rituximab for acute refractory thrombotic thrombocytopenic purpura related to acquired ADAMTS13 deficiency: a pediatric report and literature review.

OBJECTIVE: To report the case of a child with severe autoimmune thrombotic thrombocytopenic purpura (TTP) resistant to plasma exchange and steroids who was successfully treated with rituximab.
DESIGN: Case report and review of the literature on pediatric acquired TTP. The report was approved by an independent local ethics committee.
SETTING: Pediatric intensive care unit in a tertiary care children's hospital. PATIENT: A 10-yr-old boy was referred to the emergency unit with fever, vomiting, confusion, hemolytic anemia, thrombocytopenia, and mild acute renal failure. An atypical hemolytic uremic syndrome was suspected, and plasma exchange was started urgently. The patient was refractory to plasma therapy and presented critical complications. After a diagnosis of acquired TTP attributable to anti-ADAMTS13 autoantibodies had been made, he was treated with rituximab, which resulted in a stable clinical remission.
INTERVENTIONS: Rituximab therapy.
MEASUREMENTS AND MAIN RESULTS: Clinical remission.
CONCLUSIONS: TTP is a rare but life-threatening condition in children that is characterized by hemolytic anemia, thrombocytopenia, and signs of ischemic organ dysfunction. If renal involvement is present, TTP may be misdiagnosed as hemolytic uremic syndrome, but reliable screening for ADAMTS13 activity and anti-ADAMTS autoantibodies allow us to distinguish the two entities and provide adequate therapy.