Musculocutaneous neuropathy

Abstract

Introduction: Isolated musculocutaneous neuropathy is uncommon. In this study we aimed to determine its causes and clinical presentation and interpret the electrodiagnostic findings associated with this condition.

Methods: Our investigation was a retrospective review of patients diagnosed with musculocutaneous neuropathy at the Mayo Clinic (Rochester, Minnesota) electromyography (EMG) laboratory between 1997 and 2015.

Results: Thirty-two patients with musculocutaneous neuropathy and 5 patients with lateral antebrachial cutaneous neuropathy were identified. The most common cause was acute trauma or surgery (65%). Fourteen percent of the cases were idiopathic and 14% were inflammatory. Pain and sensory disturbance were more common presentations than weakness. Weakness from nerve injury was not noted in 2 patients, suggesting that other muscles may provide adequate elbow flexion/supination. The bilateral absence of lateral antebrachial cutaneous nerve sensory responses suggests an inflammatory cause.

Discussion: Musculocutaneous neuropathy usually results from trauma or iatrogenic injury. Nerve conduction studies alone are insufficient to confirm neuropathy, and needle EMG examination should be a routine part of the diagnostic evaluation. Muscle Nerve 58: 726-729, 2018.

Keywords: EMG; electrodiagnosis; iatrogenic; mononeuropathy; musculocutaneous; traumatic nerve injury.