Diabetes mellitus (DM) is pandemic, and is the leading global cause of polyneuropathy, most commonly, a distal symmetric sensorimotor polyneuropathy (DSP). By contrast, chronic inflammatory demyelinating polyneuropathy (CIDP) is rare, and characterized mainly by symmetrical proximal and distal muscles weakness. There are currently 15 sets of criteria using a variable combination of clinical, electrophysiologic, laboratory, and biopsy features to identify CIDP, but it is unclear if these criteria are the same in patients with and without DM. Slowed conduction velocity, a feature of demyelination, is observed in patients with type 1 DM with poor control, and the clinical characteristics of these patients differ from those who have CIDP and DM, suggesting a different pathophysiology. Treatment response rates in CIDP patients, with and without DM, are as high as 80 %, and it is recommended that treatment be started early to prevent secondary axonal loss. However, patients with type 1 DM with CIDP are far less likely to be treated than CIDP patients who do not have DM. In patients with type 1 DM with polyneuropathy who have prominent weakness or demyelination in electrophysiologic studies, a diagnosis of CIDP and a trial of therapy should be considered.
- Diabetic neuropathy
- Distal symmetric polyneuropathy
- Nerve biopsy