The Case of a 28-Year-Old Man With Gradually Progressive Proximal Leg Weakness

This is a case of a 28-year-old man who presented with a 6-month history of gradually progressive proximal leg weakness and pain that worsened on exercise and was relieved by rest. He had no symptoms in his upper limbs. Apart from intermittent mild ptosis and diplopia, he had no other cranial nerve symptoms. Sensation, bladder, and bowel function were normal. His examination revealed fatigable ptosis and diplopia with a positive ice-pack test. His motor examination showed mild fatigable hip flexion weakness and hyporeflexia that recovered on brief exercise. Electrophysiologic studies revealed small motor nerve amplitudes that improved with brief exercise, and a significant decrement on slow repetitive nerve stimulation. He had a positive anti-VGCC antibody. The clinical, electrophysiological, and antibody findings supported a diagnosis of Lambert Eaton Myasthenic syndrome (LEMS). LEMS commonly presents as a paraneoplastic syndrome associated with small cell lung cancer in older male smokers. However, some forms are primarily autoimmune, as was the case in our patient.