A case of Lambert-Eaton Myasthenic Syndrome with Ptosis and Dysphagia

J Korean Assoc EMG Electrodiagn Med 2006;8(2):146-148.
Published online May 10, 2006.

Abstract

Lambert-Eaton myasthenic syndrome (LEMS) is an uncommon presynaptic disorder caused by voltagegated calcium channel antibodies. Typical symptoms of LEMS include proximal leg weakness, dry mouth, and areflexia. We present an case of LEMS showing ptosis and dysphagia with normal motor power, and diagnosed as small-cell lung cancer. A 62-year-old woman was admitted because of persistent gait ataxia for two months. Diplopia, ptosis, and dysphagia were developed a week after the admission. She said these symptoms were fluctuating; becoming severe in the morning but relieved in the evening. She had normal motor power, and deep tendon reflex was hypoactive. There was no abnormal finding in the brain MRI. The amplitude of compound muscle action potentials (CMAPs) went down over 20 percent during low frequency stimulation of abductor digiti quinti muscle, but significantly went up during 50 Hz stimulation. A mediastinal mass was found in chest CT and was finally diagnosed as metastatic small-cell lung cancer. We experienced a case of LEMS combined with cerebellar degeneration initially showing gait ataxia, followed by ptosis and dysphagia.

Key Words: Lambert-Eaton myasthenic syndrome, Ptosis, Dysphagia