Approach to acute cough
Overview
Differential is broad; focus on ruling out serious illness (ex: cancer). Avoid antibiotics for viral upper respiratory infection (URI) and bronchitis. Acute cough means a cough lasting less than 3 weeks..
Assessment
Differential diagnosis
Viral respiratory syndromes or environmental irritants cause most acute cough, although the differential is very broad and overlaps with chronic cough etiologies. The focus is on ruling out serious illness, particularly pneumonia "see table 1".
Table (1). Differential diagnosis of acute cough | |
---|---|
Life threatening | Non life threatening diagnosis |
Pneumonia |
Infectious
|
Severe exacerbation of asthma or COPD |
Exacerbation of pre-existing condition
|
Heart failure | ــــــــ |
History
Elicit duration, frequency, sputum production, and associated symptoms (fever, cough, wheezing, rhinorrhea, sore throat, shortness of breath [SOB], dyspnea on exertion , paroxysmal nocturnal dyspnea [PND], orthopnea, postnasal drip, reflux, chest pain/pleuritic pain). Assess comorbidities (age > 65, asthma, COPD, CHF, immunosuppression), medications, and tobacco/drug use.
Physical exam
Vital signs including O2 sat, facial tenderness, sinus drainage, erythematous oropharynx, murmur, S3, JVD, LE edema, wheezing, crackles, rhonchi, fremitus, egophony.
Labs/tests
Consider chest X ray (CXR) if abnormal vitals (T > 38, HR > 100, RR > 24, O2 sat < 94%) OR focal lung findings (consistent with consolidation or effusion). Patients > 65 years, immunocompromised, or with pulmonary and cardiac comorbidities may present atypically with pneumonia and evaluation should be individualized. Consider other common causes such as second-hand smoke, bronchial hyperreactivity, ACE inhibitors, or recent URI with postnasal drip.
Management
Be judicious with antibiotic use, as most studies show no benefit. (likely viral; antibiotic side effects are common). If normal VS and normal exam, or normal CXR, consider symptomatic treatment for acute bronchitis with cough suppressant, bronchodilator (see Table 2), expectorant, increase fluid intake, humidify air. Recent Cochrane systematic review of 18 RCTs comparing various OTC cough preparations with placebo found no conclusive evidence of benefit of any OTC medicine, but found preparations to be generally safe. Conflicting evidence for the effectiveness of guaifenesin and dextromethorphan, with some trials reporting benefit.
If both abnormal vitals and a focal pulmonary exam are present, consider empiric antibiotics for pneumonia even if CXR is normal. Triage patients for inpatient vs outpatient management with clinical prediction tool (e.g., CURB-65). CURB-65 (1 point each for) include Confusion, BUN > 19 mg/dL, RR > 30, SBP < 90 mmHg OR DBP < 60 mmHg, Age ≥ 65 (consider inpatient for score ≥ 2). Advise rest, regular fluids, and home remedies as adjunctive therapy (lemon, honey, others).
Table (2). Medications for acute cough | ||
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Type | Medication | Comment |
Over-the-counter | Dextromethorphan |
Mechanism: cough suppressant 2 of 3 recent trials show benefit (NNT 3-8 from recent study) Dose
|
Guaifenesin |
Mechanism: respiratory expectorant 1 of 2 trials (the larger trial) showed benefit but avoid using as monotherapy. Also formulated with dextromethorphan. Dose
|
|
Antihistamine/decongestant |
Mechanism: vasoconstriction Conflicting evidence for cough suppression, but increased side effects. ACCP guidelines recommend as initial empiric therapy for common cold/URI. |
|
Prescription | Albuterol (Salbutamol) |
Mechanism: beta-agonist bronchodilator Decreases symptom duration in acute bronchitis. |
Ipratropium bromide |
Mechanism: muscarinic antagonist bronchodilator May attenuate cough related to URI or post-infectious cough. |
|
Codeine |
Mechanism: opiate cough suppressant Two trials show no difference vs placebo for cough duration. Not more effective than dextromethorphan, but more side effects, usually formulated with guaifenesin. |
|
Benzonatate |
Mechanism: anesthetizes respiratory stretch receptors. No trial data to support its use. |
|
Antibiotics |
Mechanism: varies Avoid if no evidence of pneumonia
|
|
Antivirals |
Oseltamivir (Tamiflu)
|
References
- Boujaoude ZC, Pratter MR. Clinical approach to acute cough. Lung. 2010;188 Suppl 1(Suppl 1):S41-S46.
- Ambizas EM. Acute Cough—Does Anything Help?. US Pharm. 2019;(1):8-12.
- Treatment of subacute and chronic cough in adults. UpToDate. Available at: https://www.uptodate.com/contents/treatment-of-subacute-and-chronic-cough-in-adults.