Pathogenesis of cluster headache

Schematic peripheral and central pathway representation summarizing the pathogenesis of cluster headache. Pain and autonomic features in cluster headache probably arise from activation of peripheral structures, such as the trigeminovascular system. The pathophysiology initially involves structural and functional changes in the hypothalamus and specific brain networks that transmit nociceptive input, and these functional changes can differ between cluster-bout and out-of-bout periods. In addition, anatomical and functional links between the hypothalamus and brain areas that are traditionally not considered to be involved in pain processing (such as the occipital cortex and cerebellum) are altered in cluster headache and may have contributory roles in its pathophysiology.