Background: Cranial autonomic parasympathetic symptoms (CAPS) appear in at least half of migraine patients theoretically as a result of the release of peptides by the trigemino-vascular system (TVS). Cranial pain pathways become sensitised by repeated episodes of TVS activation, leading to migraine chronification.
Objective: The objective of this article is to correlate the presence of CAPS with serum levels of vasoactive intestinal peptides (VIP) and calcitonin gene-related peptide (CGRP).
Patients and methods: Patients with chronic migraine (CM) were asked about the presence – during migraine attacks – of five CAPS, which were scored from 0 to 10 by using a quantitative scale. Serum VIP and CGRP levels were determined by ELISA.
Results: We interviewed 87 CM patients (82 females; mean age 44.7 ± 10.6 years). Seventeen had no CAPS, while 70 reported at least one CAPS. VIP levels ranged from 20.8 to 668.2 pg/ml (mean 154.5 ± 123.2). There was a significant positive correlation between scores in the CAPS scale and VIP levels (Spearman correlation coefficient = 0.227; p = 0.035). VIP levels were significantly higher in CM patients by at least one point in the scale vs those with 0 points (p = 0.002). Analysing symptoms individually, VIP levels were numerically higher in those patients with symptoms, though they were significantly higher only in those patients with lacrimation vs those without it (p = 0.013). There was no significant correlation between CGRP levels and the score in the CAPS scale.
Conclusions: Serum VIP, but not CGRP, levels seem to reflect the rate of activation of the parasympathetic arm of the TVS in migraine.