Evaluation of autonomic dysfunction in pediatric migraine patients

Introduction: Headache in childhood period is a common condition. The most important and frequent cause of primary childhood headache is migraine. The pathophysiologic mechanisms of migraine are yet to be understood. Although recent studies has showed that autonomic nervous system in adult migraine patients is affected by this condition, there are few studies evaluating this relation in childhood period. The aim of this study is to investigate autonomic dysfunction in pediatric migraine patients. Methods: Patients were admitted to Dokuz Eylül University, Faculty of Medicine, Pediatric Neurology Department between June 2013 and June 2015; and were diagnosed as migraine according to The International Classification of Headache Disorders Second Edition (ICHD-II) which had been published by International Headache Society (IHS) in 2004; who had not any chronic diseases, normal physical neurologic examination and gave consent to be a part of the study were included to the study. Thirty migraine patients and twenty control patients were included. When the patients firstly admitted to the outpatient setting, their demographic and anthropometric measurements were taken. In order to evaluate autonomic dysfunction, orthostatic test, 30:15 ratio, cold pressor test, heart rate responses to deep and normal breathing, valsalva ratio, blink reflex, sympathetic skin response test were used. Patients in control group were selected from children that had not any other diseases or headache. Results: There were 20 female (67,7%) and ten male (33,3%) patients in migraine group; 14 female (70%) and six male (30%) patients in control group. The mean age was 13,2±2,6 years (8-17 years) in migraine group and 12,7±3,5 years (7-17 years) in control group. Nineteen patients (66,3%) in migraine group had a family history of migraine. In terms of cold pressor test, sympathetic skin response test, blink reflex, heart rate responses to deep and normal breathing, statistically significant difference between two groups could not be detected. Consistantly with sympathetic hypofunction in migraine group, more frequent orthostatic hypotension (p=0,019), negative correlation between average disease duration and systolic blood pressure in lying position and fith minute in standing position during orthostatic test (p=0,013; p=0,029 respectively), negative correlation between migraine attack duration and systolic and diastolic blood pressures tenth minute during orthostatic test (p=0,047; p=0,03 respectively), negative correlation between migraine attack duration and systolic and diastolic blood pressures before cold pressure test, diastolic blood pressure and heart rate after cold pressure test (p=0,004; p=0,038; p=0,031; p=0,04, respectively) and negative correlations between PedMIDAS (Pediatric Migraine Disability Assesment Score) ans systolic blood pressure and heart rate before cold pressure test and heart rate after cold pressure test (p=0,029; p=0,029; p=0,031, respectively) were detected. In consistency with parasympathetic hyperfunction, migraine group had higher valsalva ratio (p=0,035). Negative correlation between headache fequency and heart rate response to deep and normal breathing (p=0,055; p=0,003, respectively), and negative correlation between analgesic usage frequency and heart rate response to normal breathing (p=0,041) in migraine group were considered to be related to parasympathetic hypofunction. Positive correlation between average disease duration and blink reflex R2 and R2' latency was detected in migraine group (p=0,028; p=0,027, respectively). Conclusion: Our study revealed that autonomic nervous system functions are effected in pediatric migraine and balance between sympathetic and parasympathetic nervous system is disrupted. According to blink reflex results which assess trigeminovascular pathway functions, normal R1 latency shows preservation of oligosynaptic arc. İncrease in R2, R2' latency along with the increase in disease duration reveals inhibition at interneuron level of brainstem and involvement of polysynaptic pathway that creates R2 response in patient with migraine.