Intravenous immunoglobulin is effective in patients with diabetes and with chronic inflammatory demyelinating polyneuropathy: long term follow-up.

BACKGROUND AND AIMS: Chronic inflammatory demyelinating polyneuropathy (CIDP) seems to be more common in patients with diabetes than in the general population. The long term outcome of these patients after receiving intravenous immunoglobulin is unclear and the precise optimal regimen needed has yet to be ascertained. Moreover, the influence of chronic hyperglycaemia on this neuropathy is not clear.
METHODS: This prospective follow-up study included all consecutive patients with diabetes with a CIDP referred to our department during the 18 months of the study.
RESULTS: 198 consecutive patients were referred to our neuromuscular unit and exhaustively screened. 16 patients with diabetes (8%) had a demyelinating polyneuropathy fulfilling the most restrictive diagnostic criteria for CIDP. They were treated with at least one course of intravenous immunoglobulin and, if responders, retreated in case of relapse. All patients were followed for at least 40 months. Patients with diabetes with CIDP significantly improved after immunotherapy and during follow-up. The Neuropathy Impairment Score changed from 38 at presentation to 16 at the end of the follow-up. Eight patients developed distal sensory disturbances during follow-up and four of these patients complained of distal paresthesias but no neuropathic pain. Sensory disturbances were detected after 30 months (mean time) from baseline.
CONCLUSION: CIDP is not an unusual neuropathy in patients with diabetes. Our study underlines the importance of extensively investigating patients with diabetes with polyneuropathy to identify those with a treatment responsive demyelinating polyneuropathy.