Cluster headache symptoms can include:
- ▸ Excruciating pain in or around one eye
- ▸ Tearing and redness in the affected eye
- ▸ Stuffy or runny nose on the affected side
- ▸ Drooping eyelid and decreasing pupil size on that side
They've been called more painful than broken bones, burns, or intense back pain from childbirth (“back labor”). They've been compared to having a red-hot poker stuck through your eye. They're so agonizing that they've even been called “suicide headaches.”
We're not talking about commonplace stress headaches, or the spinal headaches some people get as a result of spinal anesthesia, or even severe, chronic migraines. These “worst of the worst” headaches are called cluster headaches.
“Over the years, I've asked my patients what's worse: cluster headaches or passing a kidney stone, cluster headaches or delivering a baby, cluster headaches or any other kind of pain. They invariably say the cluster headache is the worst pain they've ever experienced,” says Richard Lipton, M.D., professor and vice chair of neurology at Albert Einstein College of Medicine and director of the Headache Center at Montefiore Medical Center in New York, NY.
Cluster headaches typically affect one side of the head and do not switch sides. They usually occur in groups or “clusters” at the same time of day or night for several weeks, abate for a stretch of time, and then start up again. For example, a person may have two cluster periods each year separated by months of freedom from symptoms; during the cluster periods, he might experience one to three headaches a day for several weeks. An increased familial risk of cluster headaches suggests that they may have a genetic component. In addition, these headaches are more common in men than women and in smokers than nonsmokers.
Fortunately, cluster headaches are much less common than other kinds of chronic headaches, affecting about a million people in the U.S. every year. By comparison, for every one person with cluster headaches, about 100 might have migraines. But that relative rarity has a downside: Much less research has been conducted on cluster headaches than, say, migraines, and they've been harder to diagnose and treat.
“Most patients with cluster headaches are misdiagnosed,” says Stephen Silberstein, M.D., professor of neurology and director of the Jefferson Headache Center at Jefferson University Hospitals in Philadelphia, PA. “Commonly, they're told instead that they have some type of migraine, or another pain syndrome called trigeminal neuralgia.”
But now, a rigorous new study published in the Journal of the American Medical Association (JAMA) confirms the effectiveness of one of the key treatments for cluster headaches: oxygen. The study may help both to raise awareness of the phenomenon of cluster headaches among general physicians and to ensure that this simple, effective treatment is covered by insurance.
“For years, specialists have believed that breathing high-flow oxygen is an effective treatment for cluster headache,” says Dr. Lipton. “But the evidence from double-blind studies wasn't nearly as strong as it is now, with this new paper.” The treatment involves breathing a high concentration of oxygen—in the study, 12 liters per minute—through a face mask for around 15 minutes at the onset of a cluster headache.
In the study, published in the December 9 edition of JAMA, investigators from the Headache Group at the University of California-San Francisco and the Institute of Neurology at the National Hospital for Neurology and Neurosurgery, Queen Square, London, compared oxygen therapy or placebo forced air in 109 adult patients during four cluster headache bouts.
After 15 minutes, 78 percent of the oxygen patients were pain-free, compared with 20 percent of the placebo forced-air patients. No significant adverse events were reported. “The authors did the world a great service with this really rigorous trial,” says Dr. Lipton.
You don't need a huge supply of oxygen to treat cluster headaches. “Most patients have about one to three attacks per day, and a cluster of attacks lasts for about six weeks,” says Dr. Silberstein. “You usually only turn a tank of oxygen on for about 10 minutes at a time, so that's about 36 hours' worth of oxygen over a six-week period.”
Oxygen therapy isn't the only acute treatment for cluster headache, but it's one of the fastest and most effective. (Acute treatments are taken at the onset of an attack.) One of the most commonly used acute treatments for cluster attacks is injectable sumatriptan, a drug developed for migraine.
“Having options that will quickly abort the attack at the beginning of the cluster phase, without an injection, is very important. Oxygen is quite safe, relatively inexpensive, and works quickly,” Dr. Lipton says. And oxygen therapy has no known side effects, unlike sumatriptan, which has side effects that can include chest pain or tightness, neck pain, numbness—and more rarely, fainting, seizures, and allergic reactions.
“In addition to acute treatments, preventive treatments are also a therapeutic mainstay,” Dr. Lipton explains. “Preventive treatments are taken on a daily basis, whether or not a headache attack is present, to reduce the frequency of attacks. But preventive treatments can take a couple of weeks to kick in, and they are rarely 100 percent effective, making acute treatments extremely important,” he adds.
Until now, however, many insurance companies have declined to pay for oxygen therapy for cluster headaches, citing a lack of data. “Medicare won't pay for cluster headaches, and neither will most insurers,” says Dr. Silberstein. “There's no ‘indication.’ Because cluster headache is something of an orphan disease, just about nothing is ‘indicated,’ and in most of the insurance coding, it's considered to be a migraine variant.”
The high profile of the JAMA paper may help to change that. “This is a publication that will be read by a wide range of physicians, and should both increase awareness of cluster headache among doctors generally, and help with reimbursement,” says Dr. Lipton. “When people with cluster headaches end up at my door, they often have been to four or five other doctors first. But now we may be able to increase the awareness of primary care providers and help see to it that insurance will pay for this very effective treatment.”