RESUMO
BACKGROUND: It has been proposed that desaturation of oxygen during an apnea event is the trigger for cluster headache. Obstructive sleep apnea has been associated with a higher than normal cardiovascular morbidity and mortality. Some obstructive sleep apnea syndrome patients lack the sleep-related, nocturnal decrease, or "dip" in blood pressure, which is seen in normal individuals. OBJECTIVE: The aim of this study is to assess whether this non-dipper pattern is present in cluster headache patients. DESIGN AND METHODS: A total of 30 normotensive cluster headache patients underwent an ambulatory blood pressure monitoring. "Non dippers" were defined as patients with a nighttime mean blood pressure fall <10%. RESULTS: Fifteen cluster headache patients (50%) were non-dippers, a frequency higher than expected. The pattern of nocturnal non-dipping is associated with a higher body mass index. Non-dipper patients displayed higher mean nighttime systolic and diastolic blood pressure. No significant difference was observed in the mean 24-hour and daytime blood pressure. CONCLUSIONS: The high incidence (50%) of non-dipper pattern in both processes, cluster headache and obstructive sleep apnea syndrome, provides support for the hypothesis of a relationship between theses 2 disorders.