Pathophysiology of migraine and clinical implications

Migraine pathophysiology is determined by genetic and environmental factors. Based on altered cerebral habituation and low serotonin levels, certain triggers can elicit a migraine attack. Following initial unspecific prodromi, an aura follows in many patients which most often consists of visual symptoms. Cortical spreading depression is the electrophysiological correlate of the aura and can activate the trigemino-vascular system. This is one potential mechanism initiating the pain process. The characteristic unilateral pulsating headache is caused by a neurogenic inflammation in the meninges. Neck pain as reported by some patients is a migraine-specific feature, the anatomical basis being the trigemino-cervical complex. Functional changes in the pain processing system maintain the headache. Among these are sensitization of trigeminal nucleus caudalis neurons and an altered antinociception descending from the periaquaductal grey. Triptans have a peripheral and central mode of action, but they are no longer effective once central sensitization has occurred.