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A review of cases of systemic vasculitis followed for one year in a rheumatology department resulted in the detection of 18 patients who on the clinical and electrophysiological evidence had symmetrical distal polyneuropathy. A moderate impairment of the motor conduction velocity was present in 7 patients, with electromyographic neurogenic changes in the distal lower limbs of all but one patient. The sensory action potential of the sural nerve was bilaterally absent in one case, and its amplitude was reduced in 14 out of 16 patients, with a decreased sensory conduction velocity in 9 cases. The sural nerve biopsy, performed in 6 patients, was prevalently suggestive of previous axonal degeneration. This investigation illustrates the spectrum of diffuse peripheral nerve involvement associated with systemic vasculitis. A variable impairment of the sensory action potential, ranging from slight decrease of amplitude to no response, is the most common finding. Conduction velocities appear to be relatively spared.

Localized nodular myositis (LNM) is a rare variant of polymyositis beginning with inflammatory nodules within muscles. Only seven cases have so far been reported in the literature. We describe a probable further case of LNM in a 67-year-old man with ischemic claudication of the left leg for three years who presented with painful nodules in the left gastrocnemius muscle and signs of systemic disease; a complete follow-up was not possible, because the patient died after only two months and autopsy was not performed. Muscle biopsy showed localized areas of necrotic and inflammatory pleomorphic changes, in keeping with the features of the other known cases. The ultrastructural findings (not previously reported in this disease) were characterized by marked changes of endomysial capillaries, with fibroblastic metamorphosis of the endothelial cells, and by the presence of filamentous inclusions in the myonuclei. The differential diagnosis of LNM from other localized muscle masses, chiefly from muscle infarct, is discussed.