A type of neurological disorder, cluster headaches are recurring, severe headaches that affect one side of the head, mostly the region around the eyes. They are relatively short but severely painful headaches that can affect the individual every day from weeks to months. They generally occur at the same time every year which is why many a times they are mistaken for allergic symptoms or stress due to other reasons. A cluster headache is so painful that it might awaken the affected person in the middle of the night with severe pain around the eyes on one side of the head.
The cluster periods which refers to the episodes of frequent attacks can be from weeks to months. These episodes are generally succeeded by relief periods or remission periods when the headaches subside. This period might last for months or for years. The period of episodes most often lasts from six weeks to twelve weeks. In case of chronic cluster periods, the pain might last for more than a year and the pain free periods might be as short as a month. During an ongoing cluster period, headaches generally occur every day, sometimes they might happen several times in a day. An attack might range from fifteen minutes to three hours. Attacks usually occur at the same time every day. Generally, episodes might start at night, waking the individual from sleep.
The headaches occur because of the activation of a specific nerve pathway situated at the base of the brain. The hypothalamus sends the signals. The affected nerve known as the trigeminal nerve is the nerve that is responsible for the feeling of sensations like hot or cold in the face. This nerve is located near the eye and extends to the forehead, cheek, down the jaw line and above the ear on the same side of the face. An underlying condition like a tumor is not the cause for these headaches.
For a headache to be called a cluster headache some other signs need to be present which include watering of the eyes, stuffiness of the nasal passage, drooping of the eyelids, changes in pupil size, redness of the conjunctiva and sweating on one side of the face. The cause is not known. Some risk factors associated with the disorder include history of tobacco exposure, a history of the disease in the family, alcohol consumption etc.
These headaches are the least common type of headaches. Cluster headaches affect less than one in one thousand people. These headaches generally affect men more than they do women. These generally start occurring before the age of thirty. They might disappear for a long time but can also start recurring without any warning. They are also known as suicide headaches.
The pain accompanying cluster headaches starts suddenly without any clear warnings but some clues about the onset of a headache can be spotted. These include redness or watering of the eyes, warm or red face, slight discomfort or a burning sensation, smaller pupil in the eye, a runny or a congested nose and a swollen eyelid. The individual might start sweating suddenly and might become sensitive to light. During a cluster period, the sensitivity to alcohol and nicotine increases, though it might not trigger anything during the remission period.
There are several factors that can trigger these headaches. For many individuals, the onset of these headaches happens when they are sleeping. People who are experiencing episodes and are in the middle of the cycle might be affected by alcohol intake. Histamines and Nitroglycerine have also been known to trigger these headaches in some people. Environmental changes, stress and change in activity levels can also be the cause of onset in some patients. Smoking and a history of the disease in the family are also some trigger factors. Seasonal variation can also be a trigger but it is inconsistent. Hormonal changes or menstruation does not seem to be a factor.
Some risk factors for cluster headaches include:
The onset of an episode of cluster headaches is sudden and does not show any signs like in case of a migraine. Distant sensations of pain might be experienced before the onset in the area of attack which is known as shadows. Sometimes these symptoms might be experienced between attacks or can be felt even after the attacks have subsided. The occurrence is mostly unilateral but instances of shifting the side of pain between episodes and sometimes bilateral headaches have also been noted.
The pain is mostly unilateral in nature, occurs on one side of the head, in the region around the eyes mostly above the eye, in the temple or may occur in any other combination. The pain is more severe as compared to any other type of headache, including migraine. The pain feels like a burning, squeezing, stabbing or boring kind of pain. Many patients have suicidal thoughts during the episodes which is why the condition is also known as suicide headaches. The headaches peak with their full force quite rapidly, within 5 or 10 minutes. The headaches mostly occur in groups (clusters). The individual headaches might be brief but they can recur many times in a single day.
Some other signs and symptoms include watering of the eyes, redness of the conjunctiva, drooping or swelling of the eyelid, runny nose, restlessness, sweating on the forehead or on the entire face, appearance of pale skin or flushing of the face, smaller pupil etc. People suffering from cluster headaches might find some relief in pacing or sitting and rocking back and forth. Some symptoms of migraine like sensitivity to light and sound can occur on one side of the head. Cluster headaches don’t make the individual queasy or wanting to throw up. But it might be possible for people with cluster headaches to develop migraine, which might have these signs. If you fund any of these symptoms, it is recommended to ask your doctor .
It is not clearly known that what causes cluster headaches. Earlier these headaches were also known as vascular headaches as it was believed that dilation of the blood vessels caused intense pain and created pressure on the trigeminal nerve. This is given less credibility now and other factors are being examined.
This condition might rarely be present in families in an autosomal dominant inheritance pattern. Individuals with a first degree relative suffering from this condition are more likely to develop it themselves. Around 65% of people affected with cluster headaches are current smokers or have been smoker in the past. But, it has been noted that quitting smoking does not help in improving the situation.
According to research, there is increased activity in the hypothalamus which controls body temperature, hunger and thirst. The cyclical nature of this condition also points to the fact that they may be linked to the biological clock which is controlled by the hypothalamus.
These headaches occur with a characteristic pain and a have a typical pattern of attacks. A diagnosis is made based on the location and severity of the pain and the attacks. There are no confirmatory tests for cluster headaches so the doctor has to depend on the information shared by the patient. Patients can maintain a headache diary which documents the timing and the location of the pain, the severity of the pain and the duration for which it lasts.
A neurological examination can be conducted where the doctor can detect physical signs corresponding to cluster headaches. Many procedures are used for assessing the functions of the brain which include testing the senses, reflexes and nerves. In case of an abnormal neurological examination or experiencing complicated headaches, some tests should be performed to rule out the risk of a serious underlying condition. A CT scan which uses X-Rays to create cross sectional images of the brain and an MRI which is used to produce detailed images of the brain and the blood vessels are generally used.
Generally diagnostic delay is experienced by most individuals. Misdiagnosis happens because of reporting of neck, nose and tooth symptoms because of which these people are referred to ENT’s for investigation of the symptoms. The average time for diagnosis in USA and Europe is around seven years. Most medical students do not receive any proper training in diagnosis and management of headaches. Some headaches that might be confused with cluster headaches are chronic paroxysmal hemicranias, short lasting unilateral neuralgiform headache with conjunctival injection and tearing and Trigeminal neuralgia.
There is no sure shot cure for cluster headaches. Treatment can help in reducing the severity of the pain, help in shortening the period of the episodes and prevent the headaches.
Some new methods of treatment are also being investigated these days. These include occipital nerve simulation in which a small device is implanted in the occipital nerve and sends impulses via electrodes. Deep brain simulation in which a simulator is implanted in the hypothalamus which might be linked to the timing of the headaches.
These treatments start once the headaches have started in order to help in suppressing them. Calcium channel blockers are most often the first choice to prevent a cluster headache. Corticosteroids might also be used in people as they can be used as fast acting pain relievers and might be effective in some people.
Using nerve blockers which means injecting some numbing agent in the area around the occipital nerve might be helpful in improving chronic cluster headaches. Lithium carbonate, used in the treatment of bipolar disorder is also effective in preventing cluster headaches. Melatonin, anti-seizure medications like topiramate might also be used as preventive medications.
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