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Cluster headache is a primary headache syndrome that is under-diagnosed and in many instances undertreated. The pain produced during a cluster headache is more severe than that generated by any other primary headache. Cluster headache is very stereotyped in its presentation and is fairly easy to diagnose with an in-depth headache history. Cluster headache is easy to treat in most individuals if the correct medications are used and the correct dosages are prescribed. This article presents information on the clinical presentation of cluster headache and both medicinal and surgical interventions.
There is no more severe pain than that sustained by a cluster headache sufferer and if not for the rather short duration of attacks most cluster sufferers would choose death rather than continue suffering. Cluster has been nicknamed the ‘suicide headache’ because cluster sufferers typically have thought about taking or have taken their lives during a cluster headache.
Diagnosis of Cluster Headache
Recently, Klapper et al.1 determined that the average time it takes for a cluster sufferer to be diagnosed correctly by the medical profession is 6.6 years. The average number of physicians seen prior to a correct diagnosis is four and the average number of incorrect diagnoses before a correct diagnosis of cluster is four. This statistic is unacceptable based on the pain and suffering cluster patients must endure when they are not treated correctly or when not being treated at all.
Cluster is a stereotypic episodic headache disorder marked by frequent attacks of short-lasting, severe, unilateral head pain with associated autonomic symptoms. A cluster headache is defined as an individual attack of head pain, while a cluster period or cycle is the time that a patient is having daily cluster headaches. Episodic cluster headache (the most common form) is defined by a cluster period lasting seven days to one year separated by a pain-free period lasting one month or longer. Chronic cluster headache is defined by attacks that occur for greater than one year without remission or with remissions lasting less than one month.
Typical cluster headache location is retro-orbital, periorbital and occipitonuchal. Maximum pain is normally retro-orbital in greater than 70% of patients. Pain quality is described as boring, stabbing, burning, or squeezing. Cluster headache intensity is always severe, never mild, although headache pain intensity may be less at the beginning and end of cluster periods. Cluster headaches that awaken a patient from sleep will be more severe than those occurring during the day.
The one-sided nature of cluster headaches is a trademark. Cluster sufferers will normally experience cluster headaches on the same side of the head their entire lives. The headaches will only shift to the other side of the headache in 15% at the next cluster period and sideshifting during the same cluster cycle will only occur in 5% of patients. The duration of individual cluster headaches is between 15 minutes and 180 minutes with greater than 75% attacks being less than 60 minutes. Attack frequency is between one to three attacks per day with most patients experiencing two or less headaches in a day. Peak time periods for daily cluster headache onset is 1am to 2am, 1pm to 3pm, and after 9pm so that most cluster patients can complete their occupation requirements without experiencing headaches during the working day. The headaches have a predilection for the first rapid eye movement (REM) sleep phase so the cluster patient will awaken with a severe headache 60 to 90 minutes after falling asleep. Cluster period duration normally lasts between two to 12 weeks and patients generally experience one or two cluster periods per year. Remission periods (headache-free time in-between cluster cycles) average six months to two years. Cluster headache is marked by its associated autonomic symptoms that typically occur on the same side as the head pain but can be bilateral. Lacrimation is the most commonly associated symptom occurring in 73% of patients followed by conjunctival injection in 60%, nasal congestion 42%, nasal rhinorrhea 22% and a partial Horner’s syndrome in 16% to 84%. Symptoms generally attributed to migraine can also occur during a cluster headache including nausea, vomiting, photophobia, and phonophobia. Photophobia and phonophobia probably occur as frequently in cluster as in migraine.Vingen et al.2 found a self-reported frequency of photophobia in 91% and phonophobia in 89% of 50 cluster patients. These symptoms may not be syndrome-specific but may just be markers of trigeminal-autonomic pathway activation.The occurrence of so called ‘migrainous symptoms’ in cluster has probably led to the high rate of misdiagnosis of cluster patients. Cluster headache is really a state of agitation as remaining motionless appears to make the pain worse. Some cluster patients state that they will lie down with a cluster headache but when questioned it has been discovered they do not lie still but roll around on the bed in agony. Many patients will develop their own routine during a cluster attack including banging their heads against a wall, crawling on the floor, taking hot showers or just screaming out in pain. Only approximately 3% can lie still during an attack.3