Autonomic Functions in Patients with Allergic Rhinitis: A Cross-sectional Observational Study

Abstract

Introduction: Allergic Rhinitis (AR) is an inflammatory disease of the nasal membranes characterised by nasal congestion, itching, rhinorrhoea, and sneezing. One of the primary factors contributing to the development of AR symptomatology is neurological. Both the Central Nervous System (CNS) and the Autonomic Nervous System (ANS) play important roles in the symptomology of such hypersensitivity reactions. Aim: To assess and compare the cardiac autonomic functions in AR patients with healthy controls. Materials and Methods: The present cross-sectional observational study was conducted in the Department of Physiology, SMS Medical College, Jaipur, Rajasthan, India from December 2021 to June 2022. Forty AR patients from the Ear, Nose and Throat (ENT) Department and 40 age and gender-matched healthy controls were enrolled from the employees working at SMS Medical College, Jaipur, Rajasthan, India. Parasympathetic function tests like the expiration to inspiration ratio, Valsalva ratio, and sympathetic function tests like Blood Pressure (BP) response to standing and BP response to sustained hand grip were performed and compared to assess the functional status of ANS in cases and controls. Primer version 6.0 was used for statistical analysis. The unpaired t-test was applied to the data of both groups, and a p-value <0.05 was considered statistically significant. Results: The increase in Diastolic BP (DBP) during isometric hand grip exercise was significantly lower in AR patients (p-value <0.001). The decrease in Systolic BP (SBP) upon immediate standing was higher in the AR group (p-value<0.001). The expiration to inspiration ratio and valsalva ratio were also significantly higher (p-value<0.05) in AR patients compared to the healthy controls. Conclusion: Patients with AR have relatively reduced sympathetic reactivity and escalated parasympathetic reactivity towards autonomic function tests compared to apparently healthy individuals. The ANS, affected in patients with AR, puts them at a greater risk of subsequent cardiovascular morbidity. Therefore, early assessment of autonomic functions should be considered for the early detection and management of such morbidities.

Keywords

• cardiovascular morbidity
• isometric exercise
• parasympathetic nervous system