How to evaluate a patient with chronic cough?

Initial evaluation of chronic cough (defined as more than 8 weeks' duration in adults and 4 weeks in children) should include a chest radiography (CXR) in most adult patients.

Patients who are taking an angiotensin-converting enzyme inhibitor (ACEi) should switch to a medication from another drug class.



Differential diagnosis of cough, a simple mnemonic is GREAT BAD CAT TOM. Click here to enlarge the image: (GERD (reflux), Laryngopharyngeal Reflux (LPR), Rhinitis (both allergic and non-allergic) with post-nasal drip (upper airway cough syndrome), Embolism, e.g. PE in adults, Asthma, TB (tuberculosis), Bronchitis, pneumonia, pertussis, Aspiration, e.g foreign body in children, Drugs, e.g. ACE inhibitor, CF in children, Cardiogenic, e.g. mitral stenosis in adults, Achalasia in adults, Thyroid enlargement, e.g. goiter, "Thoughts" (psychogenic), Other causes, Malignancy, e.g. lung cancer in adults).

The most common causes of chronic cough in adults are:

- upper airway cough syndrome (post-nasal drip)
- asthma
- gastroesophageal reflux disease (GERD)
- any combination of the above

If upper airway cough syndrome is suspected, a trial of a decongestant and an antihistamine is warranted.

The diagnosis of asthma can be confirmed with a clinical response to empiric therapy with inhaled bronchodilators or corticosteroids (spirometry is generally preferred though).

Empiric treatment for gastroesophageal reflux disease (GERD) should be initiated in lieu of testing for patients with chronic cough and reflux symptoms.

Patients should avoid exposure to cough-evoking irritants, such as cigarette smoke.

Further testing may be indicated if the cause of chronic cough is not identified and includes:

- high-resolution computed tomography (CT) of the chest
- referral to a pulmonologist or an allergist

In children, a cough lasting longer than 4 weeks is considered chronic.

The most common causes of chronic cough in children are:

- respiratory tract infections ("bronchitis" and pneumonia)
- asthma
- rhinitis with post-nasal drip
- gastroesophageal reflux disease (GERD)
- aspirated foreign body is relatively rare but must not be missed

Evaluation of children with chronic cough should include chest radiography (CXR) and spirometry (if older than 5 years of age). Skin prick test for environmental allergies can also be indicated.

References:

Evaluation of the patient with chronic cough. Benich Iii JJ, Carek PJ. Am Fam Physician. 2011 Oct 15;84(8):887-92.

Diagnosis of chronic cough in children