[Incidence of diabetic neuropathy which fulfills electrophysiologic criteria of CIDP].

In order to examine the specificity of the diagnostic criteria of CIDP, we studied 543 patients with diabetic neuropathy without clinical evidence of CIDP (307 men and 236 women, aged 60.4 +/- 11.1 years old). Moderate or severe neuropathy patients, whose polyneuropathy index (PNI) was below 80% of the normal, counted 169. Twenty out of 169 diabetic patients fulfilled the electrophysiologic criteria of CIDP. This number corresponded to more than 3.7% of the total diabetics. Motor conduction velocity category was fulfilled in 90%, conduction block in 65%, distal motor latency in 70% and F-wave latency category in 90% of 20 patients. Incomplete conduction block in the peroneal nerve and abnormally prolonged distal latency in the median nerve were frequent. These findings may reflect an overlaying focal compression. Decreased motor conduction velocity or prolonged F-wave latency were observed almost equally in every nerve. Electrophysiologic diagnostic criteria of CIDP was prepared to confirm the demyelinating nature of the neuropathy, and other demyelinating diseases should be ruled out. Diabetic patient who fulfilled this criteria was not rare. This fact is important, because clinical and CSF criteria of CIDP will be cleared in most of the diabetic patients; some diabetic neuropathy can be diagnosed as probable CIDP.