Cluster headache is the term given to a type of neurological disorder which is characterised by severe, recurrent headache which occurs unilaterally (on one side of the face) especially around the eye region. It is often accompanied by some autonomic symptoms like edema around eyes, nasal congestion and excessive eye watering. They are also known as ‘Histamine headaches’ and are classified under the primary headache disorders. These headaches appear in cycles over a period of time. The periods of time when these attacks are experienced are known as cluster periods. The attacks can occur twice or thrice a day during the cluster period.
The exact cause of such attacks is not known. But these attacks appear on the activation of a particular nerve pathway, the trigeminal autonomic reflex pathway. The activation is deep rooted in the brain in hypothalamus. The hypothalamus is responsible for our waking and sleeping cycles, known as circadian rhythm. This explains the occurrence of attacks at a particular time of the day. Some of the probable causes are genetics and smoking. About 65% of patients suffering from this disease are smokers. However, it can also occur in a non-smoker and children. Genetically, it is an autosomal recessive disorder, and can be inherited.
Cluster headaches show the following symptoms:
- Severe recurrent unilateral pain around the eye region, involving the supraorbital, periorbital and temporal regions.
- The episodes of such pain can range from once a day to as much as eight times a day.
- The pain is associated with symptoms like excessive eye watering, horehead and facial sweating, rhinorrhea (excessive mucus in the nose) and periorbital edema.
- On the basis of the pattern of attacks, they can be divided into two types:
- Episodic cluster headache: in this type, two subsequent attacks are separated by a cluster-free period of atleast more than a month. A single attack may last from a week to a year.
- Chronic cluster headache: in this type, two periods of attacks are not separated by a one month long cluster free interval.
Various treatment options are used for reduction of the span and severity of episodes. Some options used are sumatriptan and some other triptans. Breathing through oxygen mask for twenty minutes during an episode helps in reducing the pain. Intranasal lidocaine is also administered which blocks the nerve pathway. Some preventive medications used are calcium channel blockers, lithium and prednisone.
In persons with severe chronic cluster headache, surgical intervention is required which employs blockage of the nerve pathway.