Increased Resistance of the Peripheral Airways in Patients with Unexplained Chronic Cough

• Published in: Respiration Vol. 104; no. 5; pp. 303 - 310
• Main Authors: Ternesten-Hasséus, Ewa, Johansson, Ewa-Lena, Millqvist, Eva
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland 01.05.2025
• Subjects: Adult; Aged; Airway Resistance - physiology; Case-Control Studies; Chronic Cough; Chronic Disease; Clinical Investigations; Cough - etiology; Cough - physiopathology; Female; Fractional Exhaled Nitric Oxide Testing; Humans; Male; Middle Aged; Nitric Oxide; Oscillometry; Quality of Life; Spirometry; Spirometry; Chronic cough; Peripheral airways; Unexplained chronic cough; Impulse oscillometry
• ISSN: 0025-7931; 1423-0356
• DOI: 10.1159/000543008

AbstractIntroduction: Troublesome coughing that persists for more than 8 weeks without evident aetiology or effective therapy is termed unexplained chronic cough (UCC). Using impulse oscillometry (IOS) and spirometry, we assessed the functionalities of the large and small airways, respectively, in patients with UCC and in healthy control subjects. Methods: On a single occasion, 50 patients with UCC (mean age, 61 years; 82% women) and 23 subjectively healthy controls (mean age, 58.9 years; 95.7% women) underwent IOS and spirometry. Patients with UCC were also subjected to fractional exhaled nitric oxide (FeNO) measurement, and they answered a local questionnaire, a visual analogue scale (VAS) for cough and cough-related symptoms, and a health-related quality of life questionnaire. Results: Forty-nine (98%) patients with UCC reported cough symptoms from exposure to chemicals, 39 (78%) had problems with cold air, and 38 (76%) had cough symptoms following exercise. The mean VAS cough score was 62 mm in the patient group. FeNO was measured in 25 patients, showing a mean value of 16.6 ppb. Women with UCC had significantly greater airway resistance and reactance than men with UCC. The UCC group showed significantly increased peripheral airway resistance and reactance, and lower FEV1% predicted values (albeit within the normal range), as compared with the healthy control group. Conclusion: Patients with UCC show increased peripheral airway resistance and significantly lower FEV1% predicted values compared with healthy control subjects. Routine measurements of lung function with both IOS and spirometry could have added value to the diagnosis of UCC. Plain Language SummaryTroublesome coughing that persists for more than 8 weeks without evident aetiology or effective therapy is termed unexplained chronic cough (UCC). Using impulse oscillometry (IOS) (a kind of ultrasound) and spirometry, we assessed the functionalities of the large and small, peripheral airways, respectively, in patients with UCC and in healthy control subjects. On a single occasion, 50 patients with UCC and 23 subjectively healthy controls underwent IOS and spirometry. Patients with UCC also answered a questionnaire measuring quality of life and estimated their cough symptoms on a scale from 0 to 100. Forty-nine (98%) patients with UCC reported cough symptoms from exposure to chemicals, 39 (78%) had problems with cold air, and 38 (76%) had cough symptoms following exercise. The mean cough score was 62 mm in the patient group. Women with UCC had significantly greater airway resistance than men with UCC. The UCC group showed significantly increased peripheral airway resistance and reactance, and lower spirometry values (albeit within the normal range), as compared with the healthy control group. We conclude that patients with UCC show increased peripheral airway resistance and significantly lower spirometry values compared with healthy control subjects. Routine measurements of lung function with both IOS and spirometry could have added value in the diagnosis of UCC.