Combined evaluation of pupillary and cardiovascular responses to cold pressor test in cluster headache patients

Little is known about the structures and mechanisms involved in the pathoph ysiology of cluster headache (CH). In this study, pupillary and cardiovascu lar responses to the cold presser test (CPT) were monitored in CH patients during either an active phase of disease or a remission period in order to evaluate the oculocephalic and cardiovascular functioning of the autonomic nervous system in this form of idiopathic headache. CH patients showed a sp ecific pattern of pupillary response on both sides during both phases of th e disease. This response differed from that of controls because of an absen t miosis. The presser response to CPT was more marked in CH patients than i n controls. Naloxone pretreatment caused specific and selective changes in both the pupillary and cardiovascular responses of CH patients. These data suggest a systemic sympathetic hyperactivation in response to CPT in CH pat ients. hn oculocephalic sympathetic hypofunction is possibly associated as well as an altered opioid neuromodulation.