The natural history of diabetic femoral neuropathy.

Diabetic femoral neuropathy is an uncommon, unpleasant and sometimes disabling condition, on account of both pain and muscular atrophy, whose long-term prognosis has not previously been documented. We have reviewed a group of 27 patients up to 14 years (median 62 months) after diagnosis; 18 of these were re-examined after an average of nearly 4 years (median 45 months). The condition was more common in non-insulin-dependent diabetics (88 per cent), in men (59 per cent) and in older patients (median age at diagnosis 64 years). The neuropathy was bilateral (10 cases) or unilateral (17 cases); five patients with unilateral neuropathy developed femoral neuropathy on the opposite side, usually within a few weeks of the first episode. Recovery was apparent after 3 months and usually complete by 18 months; only two of the 27 patients had severe relapses. No patients remained disabled, although there were minor residual symptoms and signs in half of the patients (2 cm reduction in thigh circumference and diminished reflexes). The outlook for femoral neuropathy, even in its most severe form, is therefore very good: residual features are demonstrable but do not cause symptoms, and relapses after the first few weeks are very rare.