Headache is one of the health problems most commonly associated with significant morbidity, as well as considerable social and economic repercussions.1,2 Headaches are classified into three main types:
- Primary headaches, or headaches without known organic causes
- Secondary headaches, or headaches manifesting with symptoms due to organic causes; and
- Cranial neuralgias, facial pain, and other headaches.3
Cluster headache (CH) is a type of primary headache—one of the headache types encompassed by the term trigeminal autonomic cephalalgia.3 It is one of the most intense, excruciating headaches a patient can experience, and the diagnosis is often missed or delayed. Only 21% of patients receive a correct diagnosis of CH on first presentation, and the average patient visits three health care providers before the correct diagnosis is made.4,5 According to recently published results from the US Cluster Headache Survey,4 the diagnostic delay for CH averages five years or longer, limiting the patient’s access to correct treatment.
Patients with CH are prone to significant physical, social, and economic disability; most patients, for example, find it difficult to work during a CH period.1,2 Almost 20% of patients with CH report having lost a job because of their headaches, and about 8% are unemployed or on disability.4
Because of the pain severity and the associated impairment, the risk for suicide in the CH patient population is real.2,6,7 Jürgens et al7 report that 22% of patients with chronic CH and about 15% of those with episodic CH had suicidal tendencies; Rozen and Fishman4 report suicidal ideation in 55% of CH patients.
CHARACTERISTICS OF CLUSTER HEADACHE
As the name implies, attacks of this headache type tend to “cluster” together. In 85% to 90% of patients, CH is episodic, with cluster periods of headache attacks commonly lasting for one week to one year, and intervening remission periods that may last from one month to years.3,8 The remaining 10% to 15% of CH patients have the chronic CH type, in which cluster periods typically last for more than one year and are separated by remission periods lasting one month or less.3,8
Cluster headaches tend to occur in predictable patterns, often in the spring and fall.9-11 Most headaches begin between early evening and early morning, and patients are often awakened by CH during the night; according to responses in the US Cluster Headache Survey,4 onset times peak between midnight and 3 AM. Attacks can occur when the neck is rotated or flexed in specific ways; external pressure to the transverse processes of C4 or the nerve root of C2 can trigger a CH attack.12
Other CH triggers include alcohol (especially beer and red wine4,13), histamine, nitroglycerine, carbon dioxide, certain odors, and weather changes.3,4,11,14 Eighty percent or more of CH patients have a history of prolonged tobacco use, and at least 60% of CH patients who do not smoke were the children of smokers.15 No clear relationship has been found between CH and hormones.9,10
EPIDEMIOLOGY
Cluster headache is relatively rare, affecting about 0.1% of the population.8-10,16 Onset of the condition usually occurs between ages 20 and 40, and men are three to four times more likely to be affected than are women.3,16 A familial/genetic relationship may exist.10,17,18
DIAGNOSIS
Patient History
Diagnosis of headache relies heavily on the patient’s clinical history and physical exam.3,8,10 A detailed history should include the initial onset of CH, progression of the condition, and information about any precipitating event(s) and prodromal symptoms. Clinicians should document the pattern of pain by including specific information regarding its location, severity, quality, frequency, and duration. Of considerable value is the patient’s use of an accurate headache diary, which clinicians should encourage headache patients to maintain; in these, patients should be instructed to record the headache characteristics mentioned.3,8
Associated symptoms (assessed by conducting a complete review of systems), aggravating and alleviating factors, previous medical history, and psychosocial and family history are important in formulating the differential diagnosis, as misdiagnosis of CH is often related to inadequate history intake.13
Presentation
Cluster headaches share three main features: they are unilateral; they are associated with autonomic symptoms; and attacks tend to “cluster” in a circannual pattern (ie, clusters occurring at the same time of year) and/or circadian pattern (headache at the same time of day).8,19 The most common locations for cluster headaches are unilateral orbital, supraorbital, temporal, or a combination of these locations.3,8
About 30% of patients describe the pain as “stabbing,”3 and it is often compared to “a hot poker in the eye.” Pain peaks rapidly, usually within five to 10 minutes. It may radiate to the ipsilateral forehead, jaw, cheek, and/or teeth.3 Patients appear restless and agitated, unable to lie still.2,10 They often sit, holding their heads, and may pace the floor or bang their heads against the wall.