Palmaris Brevis Syndrome: A Treatable Pseudodystonia

BACKGROUND: Palmaris brevis syndrome, a pseudodystonia characterized by abnormal involuntary contractions of the palmaris brevis muscle which resides in the hypothenar eminence, is believed to be due to compressive irritation of motor fibers which arise from the superficial branch of the ulnar nerve. CASE REPORT: Herein, we review the origins, differential diagnosis and pathophysiology of the palmaris brevis syndrome, and effective treatment of a patient with workplace modifications and injections of botulinum toxin type A. DISCUSSION: Prompt diagnosis of the palmaris brevis syndrome facilitates effective treatment and resolution. HIGHLIGHTS: Like the task-specific hand dystonias seen in writers and musicians, palmaris brevis syndrome, a pseudodystonia, may be caused and aggravated by extreme repetitive use. Here, we report a case of palmaris brevis syndrome apparently triggered by high-volume use of a pipette and computer mouse and review relevant clinical facets from previously published cases. Treatment must include workplace modifications and may include injections of botulinum toxin.