Clinical note
Ulnar Neuropathy With Normal Electrodiagnosis and Abnormal Nerve Ultrasound

Presented as an abstract to the American Association of Neuromuscular & Electrodiagnostic Medicine, September 17–20, 2008, Providence, RI.
https://doi.org/10.1016/j.apmr.2009.10.010Get rights and content

Abstract

Yoon JS, Walker FO, Cartwright MS. Ulnar neuropathy with normal electrodiagnosis and abnormal nerve ultrasound.

Ulnar neuropathy at the elbow (UNE) is the second most common entrapment neuropathy. It is diagnosed with electrodiagnostic studies, but they can yield false-negative results. Ultrasound was used to examine 4 patients with UNE and negative electrodiagnostic findings, and it showed ulnar nerve enlargement near the elbow in all cases, with a mean cross-sectional area of 20.1mm2. This indicates that ultrasound may be a useful tool for assessing those with UNE symptoms and normal electrodiagnostic findings.

Section snippets

Patient Identification

All patients in this study presented to the Diagnostic Neurology Laboratory at Wake Forest University School of Medicine between January 2007 and January 2008 and were referred for UNE. Inclusion criteria included paresthesias in the 4th and 5th digits, abnormal clinical sensory testing in the 4th and 5th digits and the dorsum of the ulnar aspect of the hand, and weakness in ulnar-innervated intrinsic hand muscles, all of which had to be present. All participants underwent electrodiagnostic

Discussion

This is the first study to describe an increased cross-sectional area in ulnar nerves of patients suspected to have UNE but presenting with normal electrodiagnostic findings. In all cases, ultrasound of the ulnar nerve showed focal enlargement proximal to and at the medial epicondyle. In addition to absolute nerve enlargement, other changes were noted, including reduced echogenicity in 3 of the subjects and enlargement compared with the contralateral ulnar nerve. The mean cross-sectional area

Conclusions

This case series shows that some patients with UNE and normal NCSs show abnormalities when their ulnar nerves are examined with high-resolution ultrasound, including an increased nerve cross-sectional area. Further research into this topic is needed to determine the frequency with which this occurs.

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