Thrombotic microangiopathy due to malignant hypertension following corticosteroid therapy for microscopic polyangitis.

A 78-year-old woman was treated with 40 mg of prednisolone for microscopic polyangitis, and favorable effects were observed. However, her blood pressure increased and she developed severe thrombocytopenia. Thrombotic microangiopathy (TMA) due to malignant hypertension was suspected and she was treated with an angiotensin-converting enzyme inhibitor; her platelet count then rose. She showed a close temporal relationship between initiation of corticosteroid therapy and the onset of TMA. Corticosteroid therapy should be used with caution in patients with underlying vascular endothelial damage.