Microscopic polyangiitis complicated by oculomotor nerve palsy.

BACKGROUND: Microscopic polyangiitis (MPA) is a necrotizing vasculitis of the small vessels. Among the nerve lesions of MPA, the incidence of multiple mononeuritis is high, but cranial nerve palsy is rarely reported.

CASE: A female patient with oculomotor nerve palsy associated with MPA.

OBSERVATIONS: The 68-year-old patient was admitted to our hospital with a high fever, numbness and weakness of the extremities, and muscle weakness. Multiple mononeuritis and purpura were observed. The urine was positive for occult blood and protein and the creatinine level was 1.2 mg/dL, indicating renal impairment. The levels of C-reactive protein (15.5 mg/dL) and myeloperoxidase-antineutrophil cytoplasmic antibody titers (600 ELISA units) were elevated. MPA was diagnosed, and 45 mg/day prednisolone was initiated. On the fifth day after the initiation of treatment, the patient suddenly developed diplopia and blepharoptosis of the left eye. Anisocoria and decreased light reflex as well as limited supraduction, infraduction, and adduction were also observed in the eye. Left oculomotor nerve palsy was diagnosed. The palsy gradually improved with continued prednisolone treatment.

CONCLUSIONS: We encountered a rare case of MPA complicated by oculomotor nerve palsy.