[A case of microscopic polyarteritis nodosa accompanied by peripheral neuropathy]

We reported a 64-year-old woman with subacute sensorimotor polyneuropathy accompanied by marked inflammatory reactions and rapidly progressive glomerulonephritis. Polyneuropathy was followed in 3 months by a rapidly progressive renal dysfunction. Sural nerve biopsy revealed marked loss of myelinated fibers and myelin ovoid formation with vasculitis of the small-sized arteries and arterioles. Renal biopsy showed segmental necrotizing glomerulitis. These pathological findings were distinct from those of polyarteritis nodosa and led to a diagnosis of microscopic polyarteritis nodosa (MPN). Oral administration of prednisolone with an additional immunosuppressant was effective not only in alleviating the polyneuropathy, but also in preventing the deterioration of renal function. This is the first report that clearly describes the peripheral neuropathy in MPN.