All headaches are not equal: A review of migraine as a state of brain dysfunction
Individuals suffering from migraine headache, or migraineurs as they are often referred to, and the clinicians treating them are well-informed of the excruciating and debilitating nature of such episodes. However, the theoretical definition of migraine, i.e. a primary, recurrent and mostly unilateral headache characterized by throbbing pain,1 also seems to describe the presentation of often non-migraine headaches, thus somewhat failing to encompass the actual incapacitating nature of the condition. Importantly, migraine is diagnosed according to criteria stipulated by the International Headache Society (IHS)1 1) if patients experience 5 or more attacks of unilateral, pulsating, moderate to severe pain that last 4 – 72 hours, 2) if such attacks are associated with nausea and/or photo- and phonophobia, and 3) if they are aggravated by, or prevent patients from engaging in normal routine physical activity.1 Interestingly, migraine is regarded as episodic or acute if it occurs less than 15 times per month, while chronic migraine is defined as more than 15 episodes per month continuing for more than 3 consecutive months.2 Considering that a single attack can last up to 72 hours,1 and that clinicians often design therapeutic intervention based on accurate diagnoses, this classification seems somewhat counterintuitive. Indeed, patients will often regard a single migraine attack as one too many, with 15 migraine episodes per month essentially equating to permanent incapacity.3, 4
Migraine is one of the leading causes of disability worldwide—the first neurological disorder and the only headache disorder included in this list5—and occurs in up to 18% of the general population.6 The condition also demonstrates a male to female ratio of 1:3, while up to 37% of women between the ages of 25 and 55 will suffer from migraine at least once during this time.7 The fact that migraine pain originates as a neurological dysfunction and demonstrates some pathophysiological overlap with epilepsy,8 necessitates a unique approach to its management, which should be done in a manner appropriate for its phenomenology. This is an argument that we will constantly put forward and highlight throughout this review.