Thrombotic Microangiopathy Presenting with Intestinal Involvement Following Long-term Interferon-β1b Treatment for Multiple Sclerosis

Thrombotic microangiopathies (TMAs) are systemic microvascular occlusive disorders. The present report describes a patient with relapsing-remitting multiple sclerosis who had been treated with interferon (IFN)-β1b therapy for eight years and developed TMA. The patient presented with headache, thrombocytopenia, renal dysfunction, severe hypertension, posterior reversible encephalopathy syndrome, and gastrointestinal involvement. After discontinuation of the medication and initiation of antihypertensive treatment, the patient rapidly improved. This is the first report of TMA with gastrointestinal involvement (intestinal TMA) induced by IFN-β. The new onset of hypertension or headache requires careful attention in cases of long-term administration of IFN-β1b.