Primary headache disorders, such as migraine, tension headache, and cluster headache, make up nearly 98% of all headaches. Cluster headache is one of the least common types of headache and the cause is unknown. It is believed to be related to an inflammatory process resulting from an interaction between the trigeminal nerve and blood vessels in the covers of the brain. Abnormalities in the hypothalamus, a deep area of the brain that controls circadian rhythms, may be responsible for the pattern of cluster headaches.
Other primary headache types are less common and have different characteristics, such as an unusual duration or pain associated with a certain activity. Cluster headaches are characterized by severe pain of sudden onset, usually behind one eye. They are the most serious type of headache, but are less common than tension headaches and migraines. Cluster headaches tend to occur in groups, sometimes daily or several times a day.
They last 1 to 3 hours, and the pain recurs in the same way every time. Patients should be careful to avoid overuse of analgesics due to the high frequency of this type of headache. Steiner et al (201) 41 propose a three-tiered model of care in which 90% of headaches are attended by primary care physicians with minimal training in headache disorders through educational conferences given in a local setting. Approximately 98% of patients who present for medical evaluation will have a primary type of headache. Chronic migraine, drug overuse and CT scan account for the vast majority of incapacitating headaches that are misdiagnosed and poorly managed and should be referred to doctors with an interest and experience in headaches.
Migraines and tension headaches account for the vast majority of the remaining headaches (95%) that occur in primary or secondary care. The British Association for the Study of Headache and patient organisations such as Migraine Trust play an important role in educating professionals and the general public about headache disorders. Studies have focused on a specific headache disorder (and compared patients with controls without headache) and, therefore, there are no data on the diagnostic applicability of these measurements to discriminate between different primary headaches. It is important to note that the direct costs of treating headache are small compared to the huge indirect cost savings that could be achieved (for example, by reducing lost workdays) if resources were allocated to treat headache disorders appropriately. People who suffer from migraine may experience a variety of headache presentations including sinus pain, neck tension, menstrual migraine or having aura without a headache. Patients who come to the emergency department with a headache complaint should be evaluated and a distinction should be made between common primary and life-threatening secondary headaches.
Primary headaches involve biological disorders of the brain that occur with headache without evidence of underlying structural lesions. An initiative began in 2004 to raise awareness about headache disorders and improve access to quality care worldwide. Primary headaches are among the most prevalent disorders in humanity, with migraine affecting 10-14% at 1 year and tension headache above 40%.
