Multifocal motor neuropathy, type 1 diabetes and asymptomatic Hashimoto's thyroiditis: an unusual association.

Immune mediated mechanisms play a role in some forms of diabetic neuropathies. We studied a 17-year-old man who developed asymmetric weakness and atrophy in both upper arms soon after the diagnosis of type 1 diabetes. Nerve conduction studies demonstrated multifocal motor conduction blocks, and serological investigations revealed subclinical Hashimoto's thyroiditis. Therapy with intravenous immunoglobulin and cyclophosphamide led to clinical recovery. This is the first observation of an association between type 1 diabetes, multifocal motor neuropathy and Hashimoto's thyroiditis.