Entrapment neuropathies in diabetes mellitus

Neuropathy is a common complication of diabetes mellitus (DM) with a wide clinical spectrum that encompasses generalized to focal and multifocal forms. Entrapment neuropathies (EN), which are focal forms, are so frequent at any stage of the diabetic disease, that they may be considered a neurophysiological hallmark of peripheral nerve involvement in DM. Indeed, EN may be the earliest neurophysiological abnormalities in DM, particularly in the upper limbs, even in the absence of a generalized polyneuropathy, or it may be superimposed on a generalized diabetic neuropathy. This remarkable frequency of EN in diabetes is underlain by a peculiar pathophysiological background. Due to the metabolic alterations consequent to abnormal glucose metabolism, the peripheral nerves show both functional impairment and structural changes, even in the preclinical stage, making them more prone to entrapment in anatomically constrained channels. This review discusses the most common and relevant EN encountered in diabetic patient in their epidemiological, pathophysiological and diagnostic features.

Ulnar entrapment neuropathy in patients with type 2 diabetes mellitus: an electrodiagnostic study

AIMS

This study aimed to assess the prevalence and electrophysiological features of ulnar entrapment neuropathy in patients with type 2 diabetes mellitus (DM).

METHODS

Nerve conduction studies (NCS) were performed in a sample of consecutive diabetic patients aged 25-75 years, referred by the Diabetology Unit. NCS of the median, ulnar, radial, peroneal and sural nerves were performed on the non-dominant side. Median entrapment neuropathy at the wrist (MNW) and ulnar neuropathy at the elbow (UNE) and wrist (UNW) were diagnosed according to standard electrodiagnostic criteria.

RESULTS

Sixty-four patients were enrolled, 28 male (44%), average age 61, average DM duration 14.5 years. Polyneuropathy was diagnosed in 45 subjects (70%). UNE was detected in 22 patients (34%) (4 did not have polyneuropathy), in the abductor digiti minimi in 16, the first interosseus in 14 and in both in 8. UNW was detected in 7 (11%) subjects and MNW in 40 (63%). NCS alterations consistent with ulnar neuropathy were detected in a high proportion of patients (45%), suggesting that the ulnar nerve is very susceptible to focal entrapment in DM.

CONCLUSIONS

Upper limb sensory and motor NCS, including motor conduction velocity across the elbow, should be considered in the staging of DM patients.