Sleep Disorders May Trigger Cluster Headaches

The majority of people with cluster headaches may also have sleep disorders that trigger the attacks, according to a study in the June 27 issue of Neurology.

Cluster headaches, which often occur during the night, are attacks of stabbing pain on one side of the head. Attacks often come in groups, several times a day or week, and then may disappear for weeks or months. They usually last anywhere from 15 minutes to three hours. Cluster headaches are more common in men than in women. Related symptoms include eye-tearing or redness, a runny or stuffy nose, and facial sweating -- all occurring on the side of the head where the pain is felt.

For the study, 25 people with cluster headaches were evaluated in a sleep laboratory. Of those, 20 people, or 80%, showed some signs of obstructive sleep apnea, a condition in which the upper airway closes during sleep, breathing stops, and sleep is briefly but repeatedly disrupted throughout the night.

In the study, those people who reported that their headache attacks typically started in the first half of the night tended to have more severe drops in blood oxygen levels. Researchers don't know why many people with cluster headaches have sleep apnea, but one hypothesis is that the hypoxemia, or lack of oxygen in the blood, that occurs when breathing stops may trigger the attacks. The argument is bolstered by the finding in this study that more severe hypoxemia seemed linked to the early nighttime timing of the headaches.

"None of these people knew that they had sleep apnea before this study," said study author and neurologist Ronald Chervin, MD, of the University of Michigan. "It's important for sleep apnea to be diagnosed, because treatment may reduce or eliminate the headaches, not to mention the other problems that can result from sleep apnea."

Chervin said people with cluster headaches and their doctors should consider whether sleep apnea might also be a problem.

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.