[A case of myotonic dystrophy with morning headache following sleep apnea syndrome].

We reported a 39-year-old man with myotonic dystrophy. He suffered from morning headache. Respiratory function tests showed restrictive pattern and arterial gas analysis showed hypoxia and hypercapnia with respiratory acidosis (PaCO2 50.8 mmHg, PaO2 63.8mmHg, pH 7.317, SaO2 89.8%). Polysomnograph showed central apneas exclusively in light sleep (stage 1 and 2). O2 saturation fell at most to as low as 50% during the apneas. We conclude that sleep apnea should be consider in patients with myotonic dystrophy associated with morning headache.