[Neuropathy due to necrotizing vasculitis: a study of the clinical anatomy, neurophysiological characteristics, and clinical course of the disorder in 27 patients].

INTRODUCTION: Peripheral neuropathy is usually one of the initial symptoms of necrotizing vasculitis. Early diagnosis is essential for good prognosis.

OBJECTIVE: To determine which parameters are useful for early diagnosis and selection of tissue for biopsy.

PATIENTS AND METHODS: We analyzed the clinical, biological, electromyographic and anatomopathological characteristics of 26 patients with necrotizing vasculitis and peripheral neuropathy.

RESULTS: Twelve patients had panarteritis nodosa, three Churg Strauss syndrome, two Wegener s syndrome, two disseminated lupus erythematosis, one sarcoidosis and one Walderstrom s macroglobulinemia. Fifteen patients had multineuritis and the remainder distal mixed polyneuropathy which was symmetrical in three cases. In five cases biopsy was normal. Sural nerve biopsy showed the diagnosis to be correct in 20% of the patients. However, when this was done on a neurophysiologically affected nerve, the tissue was seen to be altered in 61%. Biopsy of the gastrocnemius increased the degree of usefulness to 73% when electromyographic anomalies were detected in this muscle.

CONCLUSIONS: Neurophysiological study is essential for detection of alterations in patients clinically suspected of having necrotizing vasculitis, even in cases where there is apparently no neuropathy. We recommend biopsy of the gastrocnemius muscle as the first choice in cases where sural nerve neurography is found to be normal. If the sural nerve is not normal, it is the site of choice for biopsy, and muscle biopsy is the site of second choice. When both biopsies are normal, renal biopsy should be considered to establish the diagnosis, as a third alternative.