Sleep Apnea May Cause Cluster Headaches

St. Paul, MN - June 27, 2000

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, the scientific journal of the American Academy 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.

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

"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 SA to be diagnosed, because treatment may reduce or eliminate the headaches, not to mention the other problems that can result from SA"

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

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.

Cluster headaches, which are more common in men, usually last anywhere from 15 minutes to three hours. 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.