Abstract

A 78-year-old male patient presented to Taiyuan Central Hospital with complaints of speech impairment, intermittent right eyelid drooping, and occasional diplopia. The patient, who had semantic dementia, exhibited progressively worsening symptoms. He had a medical history of coronary heart disease and hypertension. Physical examination revealed impaired short-term memory and arithmetic ability, ptosis of the right upper eyelid severe enough to cover the cornea, restricted outward movement of the left eye, and decreased bilateral knee and ankle reflexes. No other abnormalities were detected. Magnetic resonance imaging (MRI) showed cerebral infarction in the right temporal lobe. Based on these findings, differential diagnoses included myasthenia gravis and paraneoplastic neurological syndromes. Repetitive nerve stimulation and neostigmine tests supported the diagnosis of myasthenia gravis. Clinically, the coexistence of acute cerebral infarction and myasthenia gravis is rare. Due to the overlap of symptoms, the diagnosis requires a comprehensive evaluation of relevant symptoms and tests.