Autonomic features in cluster headache. Exploratory factor analysis.

The objective is to identify the pathogenesis of each autonomic manifestation in cluster headache (CH). Through a deductive statistics method (factor analysis) we analysed the type of autonomic symptoms reported by 157 CH patients. Three principal components were identified in the analysis: parasympathetic activation (lacrimation, conjunctival injection and rhinorrhoea), sympathetic defect (miosis and ptosis) and parasympathetic mediated effect (nasal congestion, eyelid oedema and forehead sweating). This work suggests that there are three different mechanisms underlying autonomic manifestations in CH.