Diabetic amyotrophy with primary involvement of shoulder girdle.

A 64-year-old diabetic man was hospitalized for painful asymmetric wasting of the proximal muscle groups of the upper extremities. No sensory impairment was noted. Results of nerve conduction and EMG studies were normal. A biopsy specimen of the left deltoid muscle revealed thickening and hyalinization of the arterial walls with significant narrowing of the lumens and mononuclear infiltration. Diabetic amyotrophy was diagnosed despite the fact that the major muscles involved were of the shoulder rather than the pelvic girdle and that the usual simultaneous affection of the lower extremities did not occur because of the arrest in muscle wasting on achieving good diabetic control. This appears to be a unique presentation of diabetic amyotrophy. Furthermore, I believe that the muscle atrophy in this patient was not neurogenic but was secondary to diabetic angiopathy.