Patients With Chronic Cough More Likely to Experience Increased Autonomic Symptoms

A study revealed that chronic cough, thought to be a neuronal hypersensitivity disorder, is linked with more frequent and severe autonomic symptoms. The results were published in ERJ Open Research.

This finding is in accordance with previous observations that patients with similar neuronal hypersensitivity disorders experience increased autonomic symptoms.

Patients with chronic cough can cough upwards of thousands of times a day. Coughing episodes stimulate the autonomic nervous system, which results in raised blood pressure and heart rate. Protracted coughing can lead to a desensitization of the autonomic system, which can subsequently lead to sympathetic dominance, autonomic imbalance, and autonomic dysfunction.

Although previous associations have been found between autonomic dysfunction and conditions characterized by neuronal/visceral hypersensitivity such as irritable bowel syndrome, fibromyalgia, and complex regional pain syndrome, this is the first study of its kind to investigate whether patients with chronic cough experience increased autonomic symptoms, the authors said.

In their study, investigators recruited 96 patients with chronic cough and 76 healthy controls from a hospital in Manchester in the United Kingdom. Participants completed the Composite Autonomic Symptom Score (COMPASS) 31 autonomic symptom questionnaire to measure self-reported autonomic symptoms and functions and results were compared between the patient population and the age- and gender-matched healthy control population.

The COMPASS questionnaire scored symptoms across 6 areas: orthostatic intolerance, vasomotor, secretomotor, gastrointestinal, bladder, and pupillomotor.

Participants also completed the Cough Quality of Life Questionnaire (CQLQ) to measure the impact of cough on daily life, and a cough severity visual analogue (VAS) scale to measure cough severity. Associations between the COMPASS questionnaire and the 2 subsequent measurement instruments were observed.

Findings showed:

• The total COMPASS 31 score was significantly higher in the patient group (median 18.4, interquartile range [IQR] 7.5­­–32.0) than the control group (median 3.6, IQR 1.1–9.5; P <.001).
• Participants with chronic cough had significantly higher symptom scores than the health volunteer groups in all domains (P ≤0.001) except vasomotor symptoms (P = .770).
• There was a positive association found between COMPASS 31 and CQLQ in the patient group (P <.001, r = 0.432) but not COMPASS 31 and VAS (P = .227).
• Patients with chronic cough scored significantly higher in all domains, save for vasomotor, on the COMPASS 31 questionnaire. The largest differences were observed in the gastrointestinal and pupillomotor domains.

The study findings indicated that patients with chronic cough experienced autonomic symptoms with substantially increased frequency and severity than healthy volunteers, suggesting that this population may be subject to autonomic dysfunction. These symptoms were predominantly observed in parasympathetically mediated systems. Whether a patient’s cough causes this effect, or if both the cough and dysfunction are part of a wider vagal pathology, is unclear and requires further investigation, the authors said.

Reference

Dockry RJ, Farrelly CL, Mitchell J, Corfield DR, Smith JA. Chronic cough is associated with increased reporting of autonomic symptoms. ERJ Open Res. 2021;7(3):00105-2021. doi:10.1183/23120541.00105-2021