Progressive polyradiculoneuropathy in diabetes: correlation of variables and clinical outcome after immunotherapy

To quantify the progression of diabetic polyradiculoneuropathy-a condition in which immune factors have been implicated-after immunotherapy.

The study evaluated 15 consecutive patients with this condition. All patients were older than 40. Four had type I diabetes and six were women. The duration of pre-existing diabetes varied from 2 to 20 years. The clinical presentation was dominated by painful progressive motor weakness, with or without exacerbation of sensory symptoms. The weakness involved all limbs, but was often asymmetric.

Electrophysiological testing showed a predominantly axonal polyneuropathy, with more recent denervating polyradiculopathy. Analysis of CSF showed increased protein in 14 and oligoclonal bands in five. Quantitative autonomic tests showed abnormalities in all patients. Sural nerve biopsy was performed in 14 patients; all showed fibre loss and segmental demyelination, four had occasional onion bulbs, and 10 showed various inflammatory infiltrates. After immunomodulating therapy, there was no further deterioration and clinical improvement occurred in all patients. Sweat responses, cardiovascular reflexes, and sural nerve fibre density correlated best with functional outcome. There was no significant difference between plasmapheresis and intravenous gammaglobulin.

Immunotherapy may improve this condition, but only certain variables correlate with rapid therapeutic response.