Cluster headache : causes and current approaches to treatment

lateral headache that occurs in association with cranial autonomic features. It is an excruciating syndrome and one of the most painful conditions known to humans, with female patients describing each attack as being worse than childbirth. In most patients, it has a striking circannual and circadian periodicity. This disorder has a highly stereotyped clinical phenotype and responds to specific therapies, thereby underlying the importance of distinguishing it from other primary headache syndromes.