Lambert–Eaton myasthenic syndrome associated with thymitis

Lambert–Eaton myasthenic syndrome (LEMS) is an autoimmune disorder characterized by a presynaptic defect of neuromuscular transmission and associated with circulating voltage-gated calcium channel antibodies. Although myasthenia gravis (MG) is often associated with thymic abnormalities, including thymitis and thymomas, these pathologic changes have not previously been associated with LEMS. A previously fit 46-year-old man presented in February 2002 with a 6-month history of general lethargy and decreased exercise tolerance. He described the sensation of “wading through water” and had difficulty climbing stairs and rising from a chair. He had no diplopia or ptosis and no abnormalities of speech or swallowing. Symptoms of autonomic dysfunction were not present. He had no relevant medical or family history and took no medication. He was a nonsmoker. Examination revealed normal optic fundi and cranial nerves. There was no muscle wasting, but he had weakness of both triceps. Otherwise, muscle power was full with no facilitation or fatigability. He …