Syringomyelia presenting as ulnar neuropathy at the elbow

Objectives: Syringomyelia may present with confusing, unilateral patterns o f segmental muscle involvement and dissociated sensory loss. The objective of this study was to report a patient with Chiari malformation type 1 (CM1) and syringomyelia who had an unusual presentation suggesting ulnar neuropa thy at the elbow. Results: A 24-year-old woman presented with clinical evidence of ulnar neur opathy at the elbow except that there was disproportionate abductor digiti mini (ADM) atrophy and weakness, equivocal ipsilateral abductor pollicis br evis weakness and hyporeflexia in both arms. Nerve conduction studies revea led marked amplitude reduction of the left ulnar ADM-compound muscle action potential (ADM-CMAP) with a normal first dorsal interosseous-CMAP amplitud e, no focal slowing or conduction block, and a normal ulnar sensory respons e amplitude. Electromyography (EMC) showed multi-segmental, left C7-T1 fibr illations acid chronic reinnervation changes. Magnetic resonance imaging (M RI) of the cervical spine demonstrated CM1 and syringomyelia. Conclusions: Syringomyelia may clinically mimic ulnar neuropathy at the elb ow. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.