Cluster Headaches

What are cluster headaches and what are the symptoms?

Cluster headaches consist of attacks of severe one-sided pain in the head. It is sometimes called migranous neuralgia. Each attack develops suddenly, usually without any warning. Typically, you feel the pain mainly in or around one eye or temple. The pain may spread to other areas on the same side of the head. The pain may be 'burning' or 'boring'. Each attack lasts 15-180 minutes, but most commonly 45-90 minutes. Attacks may occur from once every two days, to eight times a day.

The pain during an attack can be so severe that you are likely to become restless, agitated, and unable to lie down. Some people even bang their head against the wall in frustration with the pain. Attacks often occur at night and wake you from sleep.

During each attack, one or more of the following symptoms also usually occurs: redness and watering of the eye; a runny and bunged up nose; sweating of the face; swelling of the eyelids; drooping of the eyelid; constriction of the pupil in the eye.

Attacks occur in clusters (bouts). That is, a number of attacks of pain occur over a period of time and then stop. During a cluster, each attack of pain usually occurs on the same side of the head. Each cluster of attacks usually lasts for several weeks or months. Each cluster is then usually separated by months or years of remission (where no attacks occur). However, it can vary greatly from person to person as to how often the clusters occur. For example:

• A fairly typical case is for a cluster to last 6-12 weeks once a year, or once every two years, and at about the same time of year.
• Some people have more frequent clusters, some less, than the above typical situation.
• In a small number of cases only one cluster of attacks ever occurs.
• In about 1 in 10 cases, attacks continue without any remission periods. (This is called chronic cluster headache.)

Who gets cluster headaches?

Cluster headaches are uncommon. They affect about 1 in 1000 people. Men are five times more commonly affected than women. Anyone can be affected. The first cluster typically develops between the ages of 20-40 years, but it can start at any age.

What causes cluster headaches?

Research suggests that a part of the brain called the hypothalamus becomes overactive during each attack. The hypothalamus is thought to release chemicals (neurotransmitters) that may stimulate nerves cells in the brain to cause the pain and other symptoms. However, it is not known what causes this overactivity. One feature of the hypothalamus is thought to be concerned with the 'body clock' or circadian rhythms. Something to do with this 'clock function' of the hypothalamus is possibly why in many cases the clusters tend to occur at the same time each year. And, also, why during a cluster each headache attack often occurs at about the same time each day.

There may be some genetic part as in about 1 in 20 cases the condition also occurs in some other close relative.

Most cluster headaches occur for no apparent reason. However, some people find that something may 'trigger' a headache. If you find that something triggers a headache, then it is best to avoid it for the duration of a cluster period (until you are in remission). For example:

• Alcohol. Some people find that a headache often occurs within an hour or so of having an alcoholic drink. It is usually advised to stop drinking alcohol for the duration of a cluster period.
• Hot temperatures may be a trigger (such as exercising in a hot room, or a hot bath).
• Strong smelling substances such as solvents, perfumes, petrol, etc.

How is cluster headaches diagnosed?

The diagnosis is based on the typical symptoms. There is no test that can prove the diagnosis. Tests are sometimes done if the diagnosis is not clear to rule out other causes of headache.

What is the treatment for cluster headaches?

Treatment is divided into treatments to relieve ('abort') each headache, and treatments aimed at preventing the headaches.

Treating each headache

Ordinary painkillers do not work. Generally, if you take an ordinary painkiller, it takes too long to work as the headache will usually have gone before the painkiller takes effect.

Sumatriptan given by injection just under the skin is the most widely used drug to 'abort' a headache. People with cluster headaches can be shown how to use this injection themselves. Use it as soon as a headache occurs. Sumatriptan is a 'triptan' medicine that is used to treat migraine and cluster headaches. It is not a painkiller. Triptans work by interfering with a brain chemical called 5HT. An alteration in this chemical is thought to be involved in migraine and cluster headaches. Some points about sumatriptan injection:

• It works within 5-10 minutes to ease the headache in most affected people.
• The adult dose is a 6 mg injection for each headache. The maximum dose in 24 hours is two 6 mg injections (12 mg) with a minimum interval of one hour between the two doses.
• Side-effects sometimes occur, but if they do are generally mild and do not last long. They include feeling sick, dizziness, tiredness, and dry mouth. A minority of people also develop a warm-hot sensation, tightness, tingling, flushing, and feelings of heaviness or pressure in the face, arms, legs, and occasionally the chest.
• Some people should not take sumatriptan. For example, some people with heart disease, stroke disease, or peripheral vascular disease.

Sumatriptan by injection is usually the 'first-line' treatment. Other treatments that are sometimes used include: sumatriptan nasal spray, breathing 100 percent oxygen, ergotamine injections, and lignocaine nasal spray. In general, these are often not as good as sumatriptan injections and are less commonly used.

Preventing cluster headaches

Some medicines are used which aim to prevent cluster headaches. You may be advised to take one of these medicines. If used, they are taken every day throughout a cluster and then stopped when the cluster is over. You may be advised to take one long-term if you have chronic cluster headaches. It is difficult to say exactly how good they work at reducing the frequency and/or severity of headaches. This is because there is a lack of large research trials which have studied these treatments. However, smaller research studies have shown encouraging results. Briefly:

• Verapamil is the most commonly used treatment. It is a medicine that is normally used to treat heart problems. It is not clear how it works for cluster headaches. The doses used are often higher than those used for heart problems, and you may need heart tests such as ECG before increasing to high doses.
• A steroid medicine may be given at the beginning of a cluster. This may help quickly to prevent further headaches. However, you should not take it long-term due to side-effects. In some cases, a steroid medicine is started at the same time as another medicine such as verapamil, but stopped after a week or so when the effect of the other medicine has built up.
• Lithium is sometimes used. This medicine is commonly used to treat manic-depression. Again, it is not clear how it may help cluster headaches. You need regular blood checks to measure the level of lithium in the blood to make sure the dose is correct.
• Methysergide is used to prevent migraine and cluster headaches. You should not take it for more than six months as there is a risk of possible serious side-effects.
• Various other medicines are sometimes used. Also, research continues to find better treatments for this very painful condition.

Further help and advice

OUCH (UK) - Organisation For The Understanding Of Cluster Headaches
Pyramid House, 956 High Road, London N12 9RX Pyramid House
Helpline: 01646 651 979 Web: www.ouchuk.org