Neuropathy in a patient with McArdle's syndrome and diabetes mellitus.

A juvenile-type diabetic patient of five years standing presented with a mononeuritis and gave a history of painful muscle swelling induced by exertion. Failure of the blood lactate to rise during ischaemic exercise and a normal blood glucose rise following intravenous glucagon confirmed the clinical diagnosis of muscle glycogenosis. The association of diabetes and McArdle's Syndrome has not previously been documented. An ulnar nerve palsy, which persisted for many months, followed the ischaemic exercise test possibly due to compression by muscular swelling, but may have been exacerbated by the co-existing diabetes.