Alveolar hypoventilation and hyperosmnia in myotonic dystrophy.

A case of myotonic dystrophy accompanied by alveolar hypoventilation and hypersomnia is presented. Radiological studies and EMG examination of the intercostal muscles demonstrated that the respiratory muscles were affected by the disease, while polygraphic recordings showed that the alveolar hypoventilation and pulmonary hypertension worsened during sleep. The hypersomnia preceded the appearance of clinical signs of the muscular disease by many years and persisted even after treatment when the blood gas analysis values were greatly improved.