Rituximab Induced Thrombocytopenia: A Case Report

Abstract

Rituximab, an anti-CD20 monoclonal antibody, is a generally safe and well-tolerated drug. In recent years, Rituximab has been widely used off-label as the second line treatment in both adults and children with Idiopathic thrombocytopenic purpura (ITP) refractory to first line treatment. Episodes of Rituximab-induced neutropenia have been reported in some patients, but severe acute thrombocytopenia is very unusual. A 43-year-old woman, with diagnosis of Idiopathic thrombocytopenic purpura refractory to first line therapy was treated with Inj. Rituximab 500mg/week for four doses. After the 3rd dose, her platelet count had fallen from pre-infusion level of 1, 17, 000/mm3 to 79,000/mm3 but no signs of hemorrhage. So, it is diagnosed as Rituximab induced thrombocytopenia and clinician decided to delay the 4th dose by a week. After 15 days of 3rd dose, platelet count increased to 88,000/mm3. Then the 4th dose was given. Over the course of time, platelet count showed further increase. Few cases of acute thrombocytopenia with Rituximab infusion have been reported. In our case fall in platelet count was not sudden but was gradual occurring after 1st week. Rituximab-induced thrombocytopenia is likely under diagnosed because most patients do not have blood counts performed the day after treatment. Rituximab should therefore be used with caution; routine blood count should be done frequently to document this potential adverse effect. This case is reported to emphasize a rare and unusual adverse reaction to Rituximab. Early recognition of Rituximab induced thrombocytopenia is critical to prevent serious sequelae.