Improvement in cluster headache after treatment for obstructive sleep apnea.

A 60-year-old man with cluster headaches (CH), refractory to many different medications for 9 years, was found to have obstructive sleep apnea (OSA). Treatment with nasal continuous positive airway pressure (CPAP) was associated with substantial reductions in the frequency and severity of cluster headaches. These observations suggest that obstructive sleep apnea may trigger CH during susceptible periods.