Objective: To investigate the clinical characteristics, electrophysiological findings and treatment response of Lewis-Sumner syndrome (LSS).
Methods: Data of nine patients with LSS, who were diagnosed and treated from May 2008 to August 2014 in Department of Neurology, Peking University Third Hospital, were analyzed retrospectively, including clinical features, electrophysiological studies, pathological characteristics, therapy and follow up.
Results: The nine cases included seven males and two females, with the average age being 29 years old (18-64 years old). The follow-ups after treatment were between 6 months to 48 months. All 9 cases were asymmetrical onset, and the distal part of limbs was initially affected in 8 cases. Five cases presented with the initial symptom of sensorimotor, 3 cases with purely motor and only 1 case with sensory. The disease developed two forms: multifocal distribution and symmetrical distribution. Electrophysiological studies demonstrated conduction blocks on non-entrapment sites, involving mainly median nerve and ulnar nerve. Sural nerve biopsy presented mild demyelination without inflammatory infiltration. The symptoms of patients had some degrees of improvement after immunotherapy, and the prognosis was favorable.
Conclusions: Lewis-Sumner syndrome presents the initial symptoms of asymmetrical sensorimotor neuropathy mostly affecting the upper extremities. Median nerve and ulnar nerve are the most common involvements. Electrophysiological studies demonstrate motor nerve conduction block. The major finding of pathology is mild demyelinated. The patients have a positive response to immunotherapy.