Cluster headache is a disorder characterized by intermittent, severe unilateral head pain accompanied by cranial autonomic symptoms. Most cases of CH are episodic, manifesting as “in-bout” periods of frequent headache separated by month-to-year-long “out-of-bout” periods of remission. Previous imaging studies have implicated the hypothalamus and pain matrix in the pathogenesis of episodic CH. However, the pathophysiology driving the transition between in- and out-of-bout periods remains unclear.
Calcitonin gene-related peptide (CGRP) is a signaling neuropeptide released from activated trigeminal sensory afferents in headache and facial pain disorders. There are a handful of CGRP-targeted therapies currently in phase 3 studies for migraine acute treatment or prevention. Currently, 4 monoclonal antibodies targeting either the CGRP ligand or receptor are being studied for migraine prevention: ALD403 (eptinezumab), AMG 334 (erenumab), LY2951742 (galcanezumab), and TEV-48125 (fremanezumab).
Cluster headache (CH) is a rare and severe syndrome characterized by the recurrence of unilateral pain attacks, of short duration (15–180 min), and associated with ipsilateral cranial autonomic symptoms. Although, not formally included in the International Classification of Headache Disorders, hemiplegic cluster headache (HCH) is an even more rare subtype of CH in which typical attacks can be accompanied by visual, sensory, and/or aphasic migrainous auras that have a variable propensity to evolve in reversible hemi-motor symptoms.