In this article, we will look at what cluster headaches might be, their diagnosis and treatment. We will also look at any risk factors and the chronology (timing) of these disruptive events.
Contents of this article:
Here are some key points about cluster headaches. More detail and supporting information is in the main article.
- Cluster headaches normally affect one side of the head and the area around the eyes
- In northern countries, cluster headaches occur most frequently during the fall
- Cluster headaches affect around 1 in 1,000 people
- An average cluster lasts for around an hour
- Other than pain, symptoms can include a reddened eye on the affected side of the head and a stuffy nose
- Sufferers often find it hard to sit still during an attack; they may pace around
- The pain often appears almost instantly and disappears the same way
- Around 80% of people who experience cluster headaches are male
- Black people are twice as likely to experience cluster headaches as white people.
What is a cluster headache?
Cluster headaches most generally affect just one side of the head at a time.
A cluster-headache sufferer can wake up during the night because of the pain. Often, this occurs at the same time each night.
The eye on the painful side of the head may be reddened and watery. The individual's nose may be runny or blocked on the side of the nose where the pain is.
In northern countries cluster headaches tend to occur more frequently during the autumn (fall) and spring. Alcohol or extreme variations in temperature can trigger an episode during a cluster period - generally, the change in temperature refers to a rapid rise in body temperature.
Cluster headache attacks occur cyclically, hence the name. A bout of regular attacks - cluster periods - can last from a few days, weeks, to even months. This is followed by remission periods during which no headaches are felt.
Cluster headaches are not very common - they are said to affect about 1 in every 1,000 people. They affect men more often than women; about 80% of sufferers are men, most of them smokers. Fortunately, they generally have no long-term effects on the sufferer's physical health. There are drugs, such as sumatriptan, and therapies, such as oxygen therapy, available which can significantly reduce the number and intensities of headaches.
Each cluster can last from 15 minutes up to several hours - the majority of cases do not last more than an hour. Typically, a patient will suffer from one to three clusters each day.
Symptoms of cluster headachesSymptoms come on rapidly, generally without any warning.
Symptoms of cluster headaches include:
- Intense pain, some describe it as excruciating. The pain is continuous, rather than throbbing. The pain often starts around the eye, and may then radiate to other parts of the head, including the face, and down to the neck and even the shoulders. Many patients feel pain in a temple or cheek.
- The pain remains on one side of the head
- The patient becomes restless.
- The eye on the side of the pain is watery and tearful
- The eye on the side of the pain reddens
- There may be swelling around the eye on the pain side
- Stuffy, blocked, or runny nose on the pain side
- Pallor - skin of the face is pale
- Face is sometimes sweaty
- Pupil size may shrink
- Eyelid on the pain side may droop.
While migraine sufferers prefer to lie down during an attack, people with a cluster headaches say that lying down worsens the pain.
Chronology (timing) of cluster headachesA cluster period typically lasts from 1 to 12 weeks. They often start at similar calendar moments - perhaps during springtime or at some time in the fall (autumn).
Episodic cluster headaches - patients experience a series of searing headaches for about one week. Then nothing for six to twelve months. Then the week repeats itself.
- Chronic cluster headaches - in this case the cluster periods can persist for several months, even for a year or longer. While periods of remission (periods with no pain) are short; perhaps just a month long.
- Daily occurrences, with symptoms appearing several times each day.
- Just one attack, lasting from 15 minutes to up to three hours.
- Attacks occur each day at approximately the same time.
- Most attacks occur between 9pm and 9am (source: The Mayo Clinic, USA).
If you start getting headaches, it is advisable to see your doctor. Usually, headaches do not have an underlying cause (some illness or condition). However, sometimes they do. It is important for the doctor to rule out any possible underlying causes.
Risk factors for cluster headaches
Many males who experience cluster headaches are smokers.
For example, obese people are more likely to develop diabetes type 2 compared to people of normal weight. Therefore, obesity is a risk factor for diabetes type 2.
Risk factors for cluster headaches include:
- Being male - approximately 8 in every 10 sufferers are male.
- Being an adult - nearly all suffers say their cluster headaches started after they were 20 years old.
- Ethnic ancestry - people of African ancestry are twice as likely to suffer from cluster headaches, compared to Caucasian people.
- Smoking - the majority of male sufferers are smokers.
- Alcohol consumption - a significant proportion of sufferers claim that alcohol is a key trigger during a cluster period (not during remission periods).
- Genetics - if you have a close relative (parent or sibling) who has (had) cluster headaches, your risk of having them yourself is greater.
Causes of cluster headachesExperts are unsure why cluster headaches occur. Some researcher neurologists have found that during an attack there is a great deal more activity in the hypothalamus - an area of the brain that controls body temperature, hunger, and thirst.
It is suggested that perhaps that area of the brain releases chemicals that cause blood vessels to widen, resulting in a greater bloodflow to the brain, and subsequent headaches.
If the hypothalamus does act in this way, nobody knows why. We do know that such things as alcohol or a sudden rise in temperature, or exercising in hot weather may trigger attacks.
The cyclical nature of cluster headaches suggests there it may be linked to our biological clock, which is located in the hypothalamus.
Hormones - researchers have found that many people who suffer from cluster headaches have unusual levels of melatonin and cortisol during their attacks.
Apart from alcohol, cluster headaches are not linked to the consumption of any foods. No association has been found between cluster headaches and mental stress or anxiety. Even with alcohol, it is only a trigger when the sufferer is in the middle of a cluster period.
Experts say there may be a link between cluster headaches and some medications, such as nitroglycerin, which is used for the treatment of heart disease.
Treatment options for cluster headaches
Sumatriptan injections can help some cluster headache patients.
OTC (over-the-counter, no prescription required) painkillers, such as aspirin or ibuprofen are not effective for cluster headaches; because the pain comes on rapidly and goes away quickly too.
By the time the medication has started to work the headache has probably gone. Therefore, many medications and treatments for cluster headaches are either aimed more at prevention, or fast action.
Fast-acting treatments (acute treatments)
Inhaling 100% oxygen - most patients find that if they breathe in oxygen through a mask at 7 to 10 liters per minute they experience significant relief of symptoms within 15 minutes. The only problem with this therapy is that the patient has to have an oxygen cylinder and regulator close at hand - carrying them around can be cumbersome. There are some small units on the market. In some cases this kind of therapy only postpones symptoms, rather than alleviating them.
Injectable sumatriptan (limitrex) - this belongs to a class of drugs introduced in the 1990s (Triptans) for the treatment of migraine. It acts as an agonist for 5-hydroxytryptamine (5-HT) receptors. It is also an effective acute (rapid acting) treatment for cluster headaches. This type of drug may also be taken in nasal spray form - zolmitriptan (Zomig) - but only works for some patients. The adult dose is 6mg (injection); patients may take up to two injections in one 24 hour period as long as each one is at least an hour apart.
Patients with uncontrolled hypertension (high blood pressure) or ischemic heart disease should not take this drug.
Dihydroergotamine - an effective pain reliever for some sufferers. It can be taken intravenously or through inhalation. If taken intravenously, the patient needs to go have an IV (intravenous) line in a vein, which is done either in a hospital or doctor's office. Although also effective, the inhaler form is not as fast-acting.
Octreotide (Sandostatin, Sandostatin LAR) - a synthetic version of somatostatin; a brain hormone. It is injected. This effective treatment for cluster headaches is considered safe for patients with hypertension and/or ischemic heart disease.
Local anesthetic nasal drops - an example includes lidocaine (Xylocaine). It is very effective for the treatment of cluster headaches.
Surgery - if patients do not respond adequately to aggressive treatments, or cannot tolerate some medications, surgery may be recommended - even so, surgery is very rare. Surgery can only be performed once, and is only suitable for sufferers who have pain on just one side of the head. Surgical procedures include:
Conventional surgery - the surgeon cuts part of the trigeminal nerve, which serves the area behind and around the eye. This is not a procedure of first choice as there are risks to the patient's eye.
Glycerol injection - glycerol is injected into the facial nerves. This effective treatment is safer than other surgical procedures.
- Conventional surgery - the surgeon cuts part of the trigeminal nerve, which serves the area behind and around the eye. This is not a procedure of first choice as there are risks to the patient's eye.
Stimulator (still being tested) - a small device is implanted over the occipital nerve and sends impulses via electrodes. According to researchers from the Mayo Clinic, USA, a significant number of patients experienced reduced chronic headache pain.
The device appears to be well tolerated and safe to use. Another study is looking into implanting a stimulator in the hypothalamus. The National Institute for Health and Clinical Excellence (NICE), the UK body that approves drugs and therapies for National Health Service (NHS) use, has not yet assessed either treatment.
There are a number of treatment options for cluster headaches.
If a cluster headache attacks occur frequently or last for over three weeks, preventive treatments are generally needed. This means taking the treatment the moment headaches start, and throughout the period of headaches until they end.
Short-term drugs - these are taken until one of the long-term medications start working. Examples include:
Corticosteroids - these are steroids and suppress inflammation. Prednisone is an example of such a drug. For cluster headache patients it is a fast-acting preventative drug. Corticosteroids may be prescribed either for patients whose symptoms are new, or those who have very long periods of remission with short-lasting cluster periods.
Ergotamine (Ergomar) - this medication is either placed sublingually (under the tongue) or as a rectal suppository. Patients take it at night before going to bed. This medication cannot be taken together with triptans. It should not be used for long periods or for patients with poor circulation. The drug temporarily narrows blood vessels throughout the body.
Anesthetic on the occipital nerve - this nerve is located at the back of the head. By numbing it, pain messages that travel along that nerve pathway are blocked. This (injectable) treatment is stopped as soon as a long-term preventative medication starts to work.
- Corticosteroids - these are steroids and suppress inflammation. Prednisone is an example of such a drug. For cluster headache patients it is a fast-acting preventative drug. Corticosteroids may be prescribed either for patients whose symptoms are new, or those who have very long periods of remission with short-lasting cluster periods.
Long-term drugs - the patient takes these throughout the cluster period. Chronic sufferers may have to take more than one long-term medication.
Calcium channel blockers - an example is verapamil (Calan, Verelan). After the cluster period is over the doctor will gradually taper the patient off the calcium channel blocker. For chronic sufferers long-term use may be required. Patients may experience constipation, nausea, tiredness, swollen ankles, low blood pressure (hypotension), or dizziness. Calcium channel blockers were originally prescribed for patients with heart problems; when the dose is increased the patient's heart must be closely monitored with ECGs (electrocardiograms).
Lithium carbonate - an example includes Lithium (Lithobid, Eskalith). This medication is used for people with bipolar disorder, but is effective in preventing chronic cluster headaches. Patients on this medication may experience increased urination, diarrhea and tremor. The intensity of side effects is usually linked to dosage, which the doctor can alter. Patients will have regular blood tests to check for any possible kidney damage.
- Anti-seizure medications - examples include divalproex (Depakote) and topiramate (Topamax), which are anti-seizure drugs, but also effective long-term treatments for cluster headaches.
- Calcium channel blockers - an example is verapamil (Calan, Verelan). After the cluster period is over the doctor will gradually taper the patient off the calcium channel blocker. For chronic sufferers long-term use may be required. Patients may experience constipation, nausea, tiredness, swollen ankles, low blood pressure (hypotension), or dizziness. Calcium channel blockers were originally prescribed for patients with heart problems; when the dose is increased the patient's heart must be closely monitored with ECGs (electrocardiograms).
Prevention of cluster headaches
Reducing alcohol intake can minimize cluster headache attacks.
The following tips may help reduce the risk of future cluster headaches:
Alcohol - during a period when headaches occur alcohol may trigger attacks. Abstaining from alcohol during these periods will help reduce the number of headaches. Alcohol does not appear to be a trigger during periods of remission.
Inhaled nitroglycerin - this medication causes blood vessels to dilate (enlarge) and can cause headache cluster attacks. The NHS (National Health Service), UK, recommends that cluster headache sufferers avoid this medication.
Exercising in hot weather - this is a well-known trigger for cluster headaches. Sufferers should avoid doing anything which may cause their body's temperature to rise rapidly.
Smoking - a significantly higher percentage of cluster headache sufferers are smokers, compared to the rest of the population. Although not proven, some suggest that giving up smoking may help.
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