Cluster headache and chronic paroxysmal hemicrania
What are these headaches?
Cluster headache and chronic paroxysmal hemicrania (CPH) are related headaches that are quite different from migraine. The attacks are short-lasting compared with migraine attacks, and follow a typical pattern of symptoms.
Although the symptoms are so specific that the diagnosis is obvious once recognised, their rarity means that they may be misdiagnosed as migraine or another type of headache, particularly if the sufferer also has migraine. Many sufferers do not get the right treatment for several years. Although there is rarely an identifiable underlying cause, and no specific tests are necessary to confirm the diagnosis, some cases, particularly those with atypical (not conforming to type) symptoms, may be the result of other causes.
Cluster headache is an excruciatingly painful headache. It affects about 1 in 1,000 people, and is five times more common among men than women.
The condition has been known by many different names over the centuries, including migrainous neuralgia, Horton’s headache and histamine headache. The pattern of cluster headache is very typical.
The headaches usually begin to appear during the late 20s or early 30s. There seems to be some link with smoking because many sufferers are heavy smokers, either currently or in the past. Those who have never smoked will often say that their parents smoked heavily. Unfortunately, stopping smoking makes little difference to the symptoms.
As the name suggests, the attacks come in clusters, typically for several weeks once or twice a year at the same time of year. A few sufferers have chronic cluster headache with very little remission from attacks.
During a cluster period, sufferers experience an average of one to three attacks each day of very severe one-sided pain lasting between 20 minutes and 2 to 3 hours. The attacks often wake the sufferer from sleep at a similar time every night. The pain builds up rapidly to peak within a few minutes of its onset.
The headache always occurs on the same side during each cluster and is usually centred over one eye, which waters and appears bloodshot. The nostril on the affected side feels blocked and there may be a discharge. The opposite side of the head is completely unaffected.
Unlike migraine, which is aggravated by movement, cluster headache sufferers will often pace up and down, holding their head, rocking it back and forth. They may put so much pressure on the painful area or rub it so hard that it bleeds. Many sufferers will go to a window or go outside to get some fresh air. The pain is so severe and intense that some sufferers become aggressive during an attack or repeatedly hit their heads. Those who have experienced other painful conditions, such as kidney stones, say that the pain of cluster headache is much worse. The symptoms subside rapidly, but the area around the affected eye may feel ‘bruised’ between attacks.
Alcohol may trigger attacks but only during the cluster. Alcohol and other substances that dilate blood vessels, such as glyceryl trinitrate and histamine, have been used in research to provoke attacks. No other triggers have been identified and avoiding migraine triggers is irrelevant, although a few sufferers have reported a link with times of particular stress.
What causes cluster headache?
Despite intense medical research, the cause remains elusive. Much interest centres on the timing of the attacks, which appears to be linked to circadian rhythms (the biological or ‘body’ clock). Many sufferers report that their clusters are more likely to start around spring and autumn.
Recent research has highlighted changes in part of the brain called the hypothalamus, the area that controls the body clock.
Will I have it forever?
Fortunately for many sufferers, particularly those with chronic cluster headache, cluster headache does seem to improve in later life (after the age of 50).
Treatment of cluster headache
Apart from avoiding alcohol during clusters to prevent attacks the main treatment of cluster headache involves taking medication. The treatment may be acute, aimed at treating the symptoms when they start, or prophylactic, which involves taking drugs every day to try to prevent attacks developing.
Most sufferers need both acute and prophylactic drugs to control attacks during a cluster, because prophylactic drugs are rarely completely effective.
Acute (symptomatic) treatment
For many sufferers, inhaling 100 per cent oxygen, via a facial mask, is safe and effective. Oxygen should be inhaled for 10 to 20 minutes at 7 litres per minute, while in a sitting position, leaning forward.
From 1 February 2006, new regulations for home oxygen prescribing delivery came into force. Whereas before, sufferers obtained their oxygen through pharmacies from a prescription from their GP, now the GP sends a Home Oxygen Order Form to the oxygen supplier that has won the contract for each particular region. The supplier then delivers the oxygen cylinders direct to the person’s door.
All cylinders will come complete with their own integral high regulator of up to 15 litres per minute. The oxygen supplier will also provide non-rebreathing masks. Static 1,360-litre cylinders and ambulatory 460-litre cylinders, for portable use, are available.
Your doctor may prescribe injections of six milligrams of sumatriptan, given under your skin, which can be used when a cluster starts, and this gives benefit in less than ten minutes. A maximum of two injections in 24 hours is recommended. The side effects and contraindications are the same as for migraine (see ‘Living with migraine: seeing a doctor’).
Prophylactic (preventive) treatment
Drugs taken daily can reduce the frequency and severity of your attacks, making them more responsive to acute treatment. Prophylactic drugs seem to be more effective the earlier they are started in a cluster period. If they do not seem to be working, it may be that the dose is inadequate or you need a different drug.
You should continue the treatment for the usual duration of the cluster, then reduce the dose gradually over one to two weeks. If attacks break through, increase the dose until you have maintained control and then reduce it every couple of weeks until the cluster is over.
It is common for drugs to be combined to enhance their effectiveness. Drugs known as calcium channel blockers (which relax the muscle in blood vessels), such as verapamil, are usually tried first. The starting dose is low but is increased over seven to ten days. A few people need to take higher doses under close medical supervision. The most common side effect is constipation, but dizziness, fatigue and nausea may also occur.
Ergotamine can be used daily for episodic cluster headache. It should not be used regularly for chronic cluster headache, because it can cause long-term problems, constricting the blood supply to small blood vessels, particularly those in your fingers and toes. The drug is given as a suppository one to four hours before an expected attack, for example, at bedtime for night-time attacks. This strategy should be continued only for the expected duration of the cluster and for no longer than six to eight weeks.
Corticosteroids, such as prednisolone, taken by mouth can be effective at preventing a cluster if they are started early.
Methysergide (which is chemically related to ergotamine) is taken by mouth and is one of the most effective prophylactic drugs, although its long-term use has been associated with the development of scar tissue at the back of the abdomen, which can interfere with the urinary system. This complication is known as retroperitoneal fibrosis, but it is rare and has not been known to occur if a one-month drug ‘holiday’ is taken for every six months of use. Side effects of nausea, diarrhoea and muscle cramps are common, but are less likely to occur if the dose is increased slowly.
Lithium (a mineral that affects the blood chemistry) is often used in chronic cluster headache. You will need regular blood tests to make sure that the level in your bloodstream is adequate. Side effects include mild nausea, weakness and thirst, which usually wear off with continued use. Diuretic drugs (which increase the output of urine) should not be taken with lithium because they can enhance the levels of lithium in your bloodstream and result in toxic doses.
Pizotifen (a serotonin antagonist) and sodium valproate (an anticonvulsant) have been recommended by some authorities, but there is only limited evidence for their effectiveness in the treatment of cluster headache.
Several surgical strategies have been tried, including steroid injections into the occipital nerve at the back of the head on the affected side, but this usually gives only brief respite.
If a person’s symptoms are completely resistant to all other treatments, surgery of the trigeminal ganglion (a nerve junction box behind the cheek) has been advocated, although this is not without risks (interfering with sensation in the face and mouth) and cannot be guaranteed to be effective.
Chronic paroxysmal hemicrania
Chronic paroxysmal hemicrania (CPH) is also rare. Unlike cluster headache, it affects two to three times more women than men and usually starts in the early 30s. Attacks follow a typical pattern of brief attacks of excruciating one-sided pain, lasting for just a few minutes, occurring between 5 and 40 times a day.
Unlike with cluster headache, CPH sufferers prefer to sit quietly or even curl up in a ball in bed during attacks. Most sufferers notice that their eye on the affected side waters and reddens.
The cause of CPH is unknown, but the condition almost invariably responds to the anti-inflammatory drug indometacin – as a prophylactic treatment. Triggers include bending or turning the head and hormonal changes, such as those that occur with menstruation.
As with cluster headache, verapamil has also been used with beneficial effects. Drugs do not affect the tendency of the condition to fluctuate. A few sufferers need life-long therapy, but most will have periods of remission, which can last for several years.
• Cluster headaches come in episodes lasting several weeks with attacks usually occurring once or twice a year
• Acute therapy (for example, 100 per cent oxygen) can be used to treat cluster headaches, while prophylactic drugs may help to prevent attacks
• Chronic paroxysmal hemicrania (CPH) causes brief attacks of severe one-sided pain lasting for just a few minutes between 5 and 40 times a day; the attacks can be prevented with drugs