Excessive daytime sleepiness in a patient with coexisting myotonic dystrophy type 1, myasthenia gravis and Graves' disease.

A 41-year-old female with history of Graves' disease, bilateral cataract, paroxysmal atrial fibrillation was admitted because of muscle weakness, daytime sleepiness, fatigability, drowsiness, bilateral eyelid ptosis, descending of head and lower jaw. On neurological examination the patient was presented with muscle weakness, muscle atrophy (in face and sternocleidomastoid muscles), features of myotonia and apocamnosis (orbicular muscles). Electromyography revealed myopathic changes, myotonic and pseudomyotonic discharges, positive repetitive nerve stimulation test in proximal muscles. Myotonic dystrophy (MD) diagnosis was confirmed by genetic testing and myasthenia gravis (MG) by a positive titer of cholinergic receptor autoantibodies. In the CSF concentration of hypocretin was significantly decreased.