Cranial Autonomic Symptoms and Migraine: What Relationship and What Meaning? A Review.

Cranial autonomic symptoms (CAS) have been usually associated with trigeminal autonomic cephalalgias (TAC's), however in the last few years several reports in adult and pediatric population have reported important presence of the CAS in migraine. Also several evidences experimentally show that the increased parasympathetic outflow can enhance the sensitization of nociceptive receptors involved in migraine. The presence of CAS suggests an activation of the trigeminal-autonomic reflex, probably related to an over-activation of the trigeminal afferent arm. For these reasons identifing and understanding of these symptoms in migraine may be important to help in the diagnosis and effective management. The purpose of this review is, analyzing the literature data, to discuss the prevalence of these CAS in migraine, the pathophysiological meaning in the pathogenesis of migraine and whether their presence influences the prognosis and therapy of migraine in adult and pediatric age.