From the Guidelines
The evaluation of chronic cough should follow a systematic approach, starting with a thorough history, physical examination, and chest X-ray, as recommended by the most recent guidelines 1. The initial assessment should focus on the most common causes of chronic cough, including upper airway cough syndrome, asthma, and gastroesophageal reflux disease (GERD).
- A detailed history, including a thorough occupational history, should be performed in all patients, as suggested by earlier guidelines 1.
- Physical examination should concentrate on the afferent sites identified as most commonly associated with cough, and the evaluation of patients with chronic cough should include an assessment of health status and cough severity 1.
- For suspected upper airway cough syndrome, a trial of antihistamine-decongestant combination may be recommended, while for possible asthma, spirometry with bronchodilator testing should be performed 1.
- If these initial approaches fail, additional testing may include sinus imaging, induced sputum analysis, bronchoscopy, or high-resolution CT scanning of the chest, as well as a therapeutic trial of multimodality speech pathology therapy or gabapentin, as suggested by the 2016 guidelines 1. The most recent guidelines suggest that unexplained chronic cough be defined as a cough that persists longer than 8 weeks, and remains unexplained after investigation and supervised therapeutic trial(s) conducted according to published best-practice guidelines 1. Key considerations in the workup of chronic cough include:
- Chest radiograph and spirometry are mandatory 1
- Bronchial provocation testing should be performed in patients without a clinically obvious aetiology referred to a respiratory physician with chronic cough and normal spirometry 1
- High resolution computed tomography may be of use in patients with chronic cough in whom other more targeted investigations are normal 1
- Treatment effects should be formally quantified 1
- A therapeutic trial of gabapentin may be considered in adult patients with unexplained chronic cough, as long as the potential side effects and the risk-benefit profile are discussed with patients before use of the medication 1.
From the Research
Guidelines for Chronic Cough Workup
The guidelines for chronic cough workup involve a comprehensive assessment, including:
- A focused history and physical examination to identify potential causes 2, 3, 4, 5, 6
- Chest radiography as the first-line investigation to rule out concerning infectious, inflammatory, and malignant thoracic conditions 2, 3, 4, 6
- Spirometry to diagnose obstructive airway diseases, such as asthma 2, 3, 4, 6
- Empiric treatment for common causes, such as upper airway cough syndrome, asthma, and gastroesophageal reflux disease 2, 3, 4, 6
- Avoidance of exposure to cough-evoking irritants, such as cigarette smoke 2, 5
Specific Testing
Specific testing may be indicated, including:
- Fractional exhaled nitric oxide for cough variant asthma 3
- Nasal endoscopy or digital endoscopy for upper airway cough syndrome 3
- Paranasal sinus computed tomography (CT) for chronic rhinosinusitis 3
- Laryngoscopy for hoarseness 3
- Peak flow variability or bronchial challenge tests for suspected asthma 3
- Gastroesophageal reflux (GERD) investigations for patients with chronic cough without typical GERD symptoms 3
Referral to a Specialist
Referral to a specialist, such as a pulmonologist or otolaryngologist, may be indicated if the cause of chronic cough is not identified or if the patient has refractory chronic cough 2, 3, 4, 6