Nitrofurantoin-induced microangiopathic haemolytic anaemia and thrombocytopaenia in a patient with systemic lupus erythematosus.

Patients with systemic lupus erythematosus (SLE) may develop thrombotic thrombocytopaenic purpura (TTP) or TTP-like illness manifested by microangiopathic haemolytic anaemia (MAHA) and thrombocytopaenia. The distinction between active SLE and TTP is difficult because these entities share similar clinical features. Drug-induced TTP caused by an immune-mediated reaction have been documented for several drugs. Herein, we report a middle-aged Hispanic woman with long-standing SLE, who developed a TTP-like illness characterised by MAHA and thrombocytopaenia after exposure to nitrofurantoin. The patient responded well to plasmapheresis and immunosuppressive therapy and has remained clinically stable after 18 months of follow-up. To our knowledge, this is the first case that reports the association between nitrofurantoin and a TTP-like presentation.