“They often wake me in the middle of the night, a couple of hours after I’ve gone to bed. They build up in a matter of seconds and the pain is just excruciating. It’s only in my right eye, like a red hot poker. I don’t know where to put myself. I have to do something to distract from the pain. Sometimes I pace up and down the room holding my head, or just sit in the chair and rock. I cannot imagine a more severe pain.”
What is cluster headache?
Cluster Headache describes attacks of severe one-sided pain in the head, usually around the eye. The pain is associated with autonomic change in or around the eye. This means watering (including a runny nose), redness, eyelid closure, a small pupil, skin redness or sweating. Periods of attacks are known as bouts in which the pain is clustered (hence the name) over a few weeks or months.
Who gets cluster headache?
Cluster Headache is relatively uncommon but affects at least 4 in 1000 people. Men are more often affected than women (unlike most other types of headache). Women with cluster say it’s worse than childbirth. It can start at any age, most often in younger adults.
What are the different types of cluster headache?
The more common type (90%) is episodic cluster headache. This comes and goes, at worst a few bouts a year lasting, more often between twice a year and once on two years. Intriguingly, bouts are commoner in spring and in autumn.
Chronic cluster is fortunately less common (10%) and simply means the same sort of pain, going on for six months of more. In chronic cluster the pain may be continuous.
What are the symptoms of cluster headache?
Cluster Headache is extremely painful – so severe that it has been called ‘suicide’ headache.
Within a bout, pain always stays on the same side. A minority of patients find cluster changes sides from bout to bout.
The pain is often described as searing, knifelike or boring, especially in and around the eye. The pain reaches full force rapidly, within 5-10 minutes of onset, and each untreated attack typically lasts up to an hour but can be anything between 15 minutes and 3 hours.
In contrast to migraine, when most people want to rest during an attack, the pain of cluster pain tends to make the patient restless or active, even to the point of banging their head on the wall.
Pain is often at the same time every night (“alarm clock pain”) and typically also occurs within minutes of drinking alcohol, so it is unusual to see a cluster patient who carries on drinking through a bout.
Do I need any tests?
No. One study, surprisingly, showed an excess of pituitary gland abnormalities in people with cluster, leading some experts to scan the brain and pituitary in patients with new cluster headache.
People taking verapamil for cluster headache are often recommended to have an electrocardiogram before and during treatment with verapamil, to rule out heart rhythm problems which can be caused or worsened by this drug.
What causes cluster headache?
Cluster, like migraine, is a primary headache, in other words it arises from an error of nerve function. Using a computing analogy, it is a software problem. A minority of experts see cluster as a variant of migraine, though unlike migraine cluster is not worsened by repetitive acute treatments, and localizes to a different part of the brain, the midbrain, also known as the posterior hypothalamus or peri-aqueductal gray matter. This fits in with the sleep and seasonal variation. Migraine arises lower down, in the brainstem or trigeminal nucleus.
What are triggers for cluster headache?
Usually there are no triggers, but alcohol can bring on an attack though zero alcohol does not abolish the bout. Cluster associates with smoking, though quitting smoking has not been shown to help. Other recognised triggers include exercise and elevated environmental temperatures. Other than not drinking alcohol, and the fact we all need to be non-smokers, addressing triggers is much less helpful for cluster than it is for migraine.
Will it get better?
Fortunately for many sufferers, particularly those with chronic cluster headache, cluster often improves in later life. Bouts of episodic cluster are by definition guaranteed to improve naturally, though tend to recur in the fullness of time.
What can I do to help myself?
Ordinary painkillers do not work and simply “muddy the water” with side effects. Effective treatment requires medical advice as prescription-only drugs are needed.
Cluster is uncommon so many non-specialist doctors have never seen a case. It may therefore be helpful to download selectively from www.ouchuk.org (the organisation to understand cluster headache) or bring this factsheet to show to your doctor; this requires tact as many doctors are understandably wary of second opinions from Dr Google!
What treatment can I take?
Either you put up with the excruciating pain, or take medication.
Unless you have a very special GP, you will need to see a expert in headache. Such experts are often saddened to encounter people with decades of cluster headache who have had neither diagnosis nor treatment for this seriously painful condition.
For episodic cluster, the usual starting regime is:
ā Sumatriptan 6mg injection for each episode of pain, taken as soon as possible after the start of pain. This normally works within minutes.
ā Prednisolone 70mg daily after breakfast for a week with brisk taper thereafter to zero. This aborts the bout in 70% and allows time for verapamil to start working.
ā Verapamil 80mg or 120mg three times daily, if electrocardiogram is normal. Continue until the bout is over – which is normally obvious to the patient.
Many respond to verapamil 120mg 3 times daily, but higher doses, up to 360mg three times daily may be necessary. An electrocardiogram (ECG) should be taken before verapamil is started and repeated as the dose is increased. The effective dose should be continued for the usual duration of the cluster, and then gradually tapered over a few weeks. If attacks recur, the dose can be increased again and reduced at 2-week intervals. Verapamil is usually well tolerated although constipation (which may be severe) acid indigestion and flushing can happen. Good dental care (flossing) is important as gum bleeding from gum overgrowth (gingival hyperplasia) can occur.
Other Cluster Treatments
High dose (100%) oxygen is a possible alternative to sumatriptan, though can be a fiddle to set up. The correct kit is required. 100% oxygen is delivered at 7-12 litres per minute through a non-rebreathing mask for 10-20 minutes. You should sit leaning forward with the mask firmly over your face ensuring it is a tight fit and there are no leaks. To obtain oxygen as an initial emergency order, your GP can send a Home Oxygen Order Form (HOOF) to the oxygen supplier who has the contract for your region. A second non-urgent HOOF should be completed at the same time for your ongoing supply. If you live in Scotland, your GP will write a prescription for oxygen and you will need to obtain a high flow regulator. Some people find that oxygen simply time-shifts the attack.
Triptans other than subcutaneous sumatriptan are best avoided as their latency to benefit (1-2 hours) is too long.
Alternatives to verapamil include methysergide, valproate, lithium, and melatonin.
Greater occipital nerve (GON) block is worth considering; as is a trial of indometacin as cluster can be mistaken for a hemicrania.
Refractory cases may be considered for neurosurgical treatment with brain or occipital nerve stimulation.
Non-specialists should have a low threshold for referring patients with cluster headache to an expert.
This information is provided as a general guide only. If you have any queries or concerns about your headaches or medications please discuss them with your GP or your National Migraine Centre Doctor.