P-PN007. A case presenting with clinical and laboratory characteristics of fisher syndrome and lambert-eaten myasthenic syndrome (LEMS)

Abstract

Introduction . Although Fisher syndrome and LEMS are classified into autoimmune neuromuscular diseases, we cannot find the coincidence of them in a single patient in the previous literature. Results . A 70-year-old female was admitted to our hospital because of bilateral hand numbness, double vision and unsteadiness which had developed 2 weeks. She had no history of preceding infection and/or related illness. On admission, her condition was characterized by mydriasis, extraocular muscle weakness, mild proximal muscle weakness and truncal ataxia. In addition, the tendon reflexes were absent at rest, and improved with brief exercise. Motor nerve conduction studies showed significantly low compound muscle action potentials (CMAPs) and increments of more than 200% after brief exercise (post-exercise facilitation) in several nerves. Sensory nerve conduction studies showed significantly low sensory nerve action potential (SNAPs) of median and ulnar nerves, and normal SNAPs of sural nerves. We also demonstrated the impairment of neuromuscular transmission in several muscles based on abnormal decrements in the repetitive nerve stimulation (RNS) test and abnormal jitter in the single-fiber electromyography (SFEMG). Both anti-GQ1b and GT1a ganglioside antibodies and P/Q-type voltage-gated calcium channel (VGCC) antibodies were positive in her sera. Her conditions improved spontaneously. She accomplished walking alone in six weeks, and paralysis of the eye muscles recovered in five months. Median and ulnar SNAPs returned to normal in accordance with recovery of clinical findings. On the other hand, low CMAPs with post-exercise facilitation remained after complete recovery. Positron emission tomography and gastrointestinal endoscopy did not show any malignancy. Conclusion . Some electrophysiological studies revealed the impairment of neuromuscular transmission using RNS and/or SFEMG in patients with Fisher syndrome. Also, it has been known that autoimmune neurological phenotypes are diverse among patients with P/Q-type VGCC antibodies. This may be the first case who showed clinical and laboratory characteristics of Fisher syndrome and LEMS simultaneously.