What are cluster headaches?
Cluster headache is a devastating, painful affliction. Unlike episodic migraine and chronic migraine, this condition primarily affects men. Cluster headache is a periodic (30-90 minute) attack of severe pain, primarily localized to the eye, temple, forehead, or cheek region. Up to 50% of patients may have tenderness at the base of the skull and neck on the same side as the headache pain.
The term "cluster headache" was originally used to describe the clustering or bouts of painful attacks that occur for weeks to months at a time and then spontaneously terminate. The headache cycle may return weeks or months later. The interval between cycles is called the interim. It is now recognized that a chronic form of cluster headache exists in which recurring attacks, without interim, occur for years at a time.
Key clinical features
As stated above, cluster headache occurs predominantly in males, compared with the female to male ratio (3:1) of migraine. The frequency of attacks is 1-6 times per day. Alcohol typically provokes an attack. Many cluster headache patients are heavy smokers and alcohol drinkers. Attacks frequently occur during sleep or napping times. Each attack of cluster headache is usually accompanied by same side eye watering and nasal drainage, eye lid drooping, pupillary change, and eye congestion/redness.
What is the prevalence of cluster headache?
The prevalence of cluster headache is reported to be approximately 0.1-0.3% of the population, though some estimates are higher. The attacks can begin at any age, although they usually occur between the ages of 20 and 40 years. A family history of cluster headache is occasionally present (as well as an increased prevalence of migraine).
What is the proposed mechanism of cluster headache?
Currently, the exact mechanism of cluster headache remains uncertain. The sphenopalatine ganglion and cavernous sinus are among the sites previously considered potentially important for cluster headache pathogenesis. Most recently, PET scanning techniques have revealed the region of the brain known as hypothalamus is important in cluster headache pathogenesis (May, 1998). Critical melatonin function, which regulates the biological clock, may also be altered (Leone, 1997).
What specific exams or tests are performed for determining cluster headaches?
The neurological examination of cluster headache is normal, except for changes during the headache that might include eyelid drooping, pupillary change, etc. There are no specific diagnostic tests for cluster headache, although provocation with alcohol is considered a key and reliable feature.