Overview
Acute Cough
1. Clinical Overview
Summary
Acute cough (<3 weeks) is most commonly viral URI or acute bronchitis: self-limited, no antibiotics needed. Key: rule out pneumonia (fever, hypoxia, crackles) and PE. Antibiotics are a stewardship priority - NOT for acute bronchitis.
Key Facts
- Definition: Cough <3 weeks duration
- Common cause: Viral URI (40-50%), acute bronchitis (10-20%)
- Key rule: No antibiotics for acute bronchitis
- Red flag: Fever + hypoxia + productive cough = pneumonia
2. Epidemiology
Overview
Acute cough is defined as cough lasting less than 3 weeks. The most common causes are viral upper respiratory infections (URI) and acute bronchitis, which are self-limited. Key ED tasks include ruling out serious causes (pneumonia, PE, CHF), avoiding unnecessary antibiotic prescribing, and providing symptomatic relief.
Classification
By Duration:
| Type | Duration |
|---|---|
| Acute | <3 weeks |
| Subacute | 3-8 weeks |
| Chronic | > weeks |
Epidemiology
- Extremely common: One of the most frequent reasons for medical visits
- Viral URI most common cause: 40-50% of acute cough
- Acute bronchitis: 10-20%
- Pneumonia: 5-10%
Etiology
Infectious (Most Common):
| Cause | Notes |
|---|---|
| Viral URI | Rhinovirus, coronavirus, influenza, RSV |
| Acute bronchitis | Usually viral; minimal productive cough |
| Pneumonia | Bacterial, viral, atypical |
| Pertussis | Paroxysmal, prolonged cough |
| Influenza | Systemic symptoms |
Non-Infectious:
| Cause | Notes |
|---|---|
| Asthma exacerbation | Wheezing, history of asthma |
| COPD exacerbation | Smoking history, dyspnea |
| Pulmonary embolism | Dyspnea, risk factors |
| CHF exacerbation | Orthopnea, edema |
| ACE inhibitor cough | Dry, persistent |
| GERD | Worse postprandially |
3. Pathophysiology
Mechanism
Viral URI/Acute Bronchitis:
- Viral infection of upper or lower airways
- Inflammatory response → Increased mucus, cough reflex
- Self-limited; resolves in 1-3 weeks
Pneumonia:
- Bacterial/Viral infection of lung parenchyma
- Consolidation → Impaired gas exchange
- Systemic inflammatory response
4. Clinical Presentation
Symptoms
| Symptom | Viral URI/Bronchitis | Pneumonia |
|---|---|---|
| Cough | Dry or mildly productive | Productive, purulent |
| Fever | Low-grade or absent | Often high |
| Dyspnea | Minimal | May be significant |
| Systemic symptoms | Mild | Fatigue, malaise, rigors |
| Chest pain | Absent or mild | Pleuritic |
History
Key Questions:
Physical Examination
| Finding | Significance |
|---|---|
| Fever | Infection |
| Tachypnea | Pneumonia, PE |
| Hypoxia | Pneumonia, PE, CHF |
| Crackles/Rhonchi | Pneumonia |
| Wheezing | Asthma, COPD, bronchitis |
| Dullness to percussion | Consolidation, effusion |
| Egophony | Consolidation |
Duration of cough
Common presentation.
Productive or dry
Common presentation.
Color of sputum
Common presentation.
Fever, chills
Common presentation.
Dyspnea
Common presentation.
Hemoptysis
Common presentation.
Weight loss, night sweats
Common presentation.
Smoking history
Common presentation.
ACE inhibitor use
Common presentation.
Sick contacts
Common presentation.
Travel (TB, endemic fungi)
Common presentation.
Immunocompromise
Common presentation.
5. Clinical Examination
(Integrated into Clinical Presentation above)
Red Flags
Serious Causes to Consider
| Finding | Concern | Action |
|---|---|---|
| Hypoxia | Pneumonia, PE | Chest X-ray, ABG |
| High fever, rigors | Pneumonia | Chest X-ray |
| Hemoptysis | Pneumonia, TB, malignancy, PE | Imaging |
| Dyspnea, pleuritic pain | PE | D-dimer, CTA |
| Weight loss, night sweats | TB, malignancy | CXR, workup |
| Immunocompromised | Opportunistic infection | Broader workup |
6. Investigations
Differential Diagnosis
| Diagnosis | Key Features |
|---|---|
| Viral URI | Nasal symptoms, mild |
| Acute bronchitis | Cough predominant, minimal fever |
| Pneumonia | Fever, productive cough, hypoxia |
| Influenza | Systemic symptoms, season |
| Pertussis | Paroxysmal, post-tussive vomiting |
| Asthma exacerbation | Wheezing, prior history |
| COPD exacerbation | Smoking, baseline dyspnea |
| PE | Dyspnea, pleuritic pain, risk factors |
| CHF | Orthopnea, edema |
Diagnostic Approach
Clinical Diagnosis
- Most acute cough is viral and can be diagnosed clinically
- No routine testing needed if uncomplicated
When to Image
Chest X-ray Indications:
| Indication | Notes |
|---|---|
| Fever + productive cough | Pneumonia suspected |
| Hypoxia | Pneumonia, PE |
| Hemoptysis | Pneumonia, TB, malignancy |
| Abnormal lung exam | Crackles, consolidation |
| Elderly or immunocompromised | Lower threshold |
Laboratory
| Test | Indication |
|---|---|
| CBC | Infection, leukocytosis |
| Procalcitonin | Differentiate bacterial vs viral |
| D-dimer | PE suspected |
| Influenza testing | Seasonal, for treatment timing |
| COVID-19 testing | If clinically indicated |
| Sputum culture | Severe or atypical pneumonia |
7. Management
Principles
- Most acute cough is viral: Supportive care only
- Antibiotics NOT indicated for acute bronchitis
- Antibiotics for pneumonia: Based on severity and likely pathogens
- Symptomatic relief: Antitussives, hydration
Viral URI / Acute Bronchitis (Supportive)
| Intervention | Details |
|---|---|
| Rest and fluids | Hydration |
| Honey | 1-2 tsp, especially at night (adults) |
| Dextromethorphan | 10-30 mg q4-6h (antitussive) |
| Guaifenesin | 200-400 mg q4h (expectorant) |
| Nasal decongestants | Pseudoephedrine, oxymetazoline |
| Analgesics | Acetaminophen, ibuprofen for discomfort |
NOT Recommended:
- Antibiotics (no benefit, promotes resistance)
Pneumonia
Outpatient (Low Risk):
| Agent | Dose | Duration |
|---|---|---|
| Amoxicillin | 1 g TID | 5 days |
| Doxycycline | 100 mg BID | 5 days |
| Azithromycin | 500 mg × 1, then 250 mg × 4 days | 5 days |
Inpatient (Non-ICU):
| Regimen | Notes |
|---|---|
| Respiratory fluoroquinolone (levofloxacin, moxifloxacin) | Monotherapy |
| OR Beta-lactam + Macrolide | Ceftriaxone + azithromycin |
Pertussis
| Agent | Dose | Duration |
|---|---|---|
| Azithromycin | 500 mg × 1, then 250 mg × 4 days | 5 days |
| Clarithromycin | 500 mg BID | 7 days |
| TMP-SMX | 1 DS BID (if macrolide allergy) | 14 days |
Asthma/COPD Exacerbation
| Intervention | Details |
|---|---|
| Bronchodilators | Albuterol nebulizer |
| Systemic steroids | Prednisone 40 mg × 5 days |
| Antibiotics | For COPD with purulent sputum |
8. Complications
Disposition
Discharge Criteria
- Uncomplicated acute bronchitis or URI
- Mild pneumonia (low CURB-65 or PSI)
- Able to tolerate oral medications
- Adequate oxygenation
- Reliable follow-up
Admission Criteria
- Severe pneumonia (high CURB-65 or PSI)
- Hypoxia requiring supplemental O2
- Unable to tolerate oral intake
- Significant comorbidities
- Hemodynamic instability
Follow-Up
| Situation | Follow-Up |
|---|---|
| Acute bronchitis | PCP if not improved in 2-3 weeks |
| Outpatient pneumonia | PCP in 2-3 days |
11. Patient/Layperson Explanation
Condition Explanation
- "You have a viral infection causing your cough. It will get better on its own in 1-3 weeks."
- "Antibiotics won't help viral infections and can cause side effects."
- "We will give you medicine to help with the symptoms."
Home Care
- Rest and drink plenty of fluids
- Use honey for cough relief
- Take over-the-counter cough suppressants as directed
- Use a humidifier
Warning Signs to Return
- Shortness of breath
- High fever (>101°F) or fever lasting >3 days
- Coughing up blood
- Chest pain
- Worsening symptoms
9. Prognosis & Outcomes
Special Populations
Elderly
- Higher risk of pneumonia
- Atypical presentations (no fever)
- Lower threshold for imaging and admission
Immunocompromised
- Broader differential (PCP, fungal, CMV)
- More aggressive workup
- Lower threshold for admission
Smokers
- Higher risk of pneumonia and COPD
- Consider malignancy if prolonged cough, hemoptysis
Quality Metrics
Performance Indicators
| Metric | Target | Rationale |
|---|---|---|
| Avoid antibiotics for acute bronchitis | >0% | Stewardship |
| Chest X-ray if pneumonia suspected | 100% | Diagnosis |
| Appropriate antibiotic for pneumonia | >0% | Guideline adherence |
Documentation Requirements
- Duration and character of cough
- Red flag assessment
- Chest X-ray result (if obtained)
- Rationale for antibiotic (if prescribed)
- Discharge instructions
10. Evidence & Guidelines
Key Clinical Pearls
Diagnostic Pearls
- Most acute cough is viral: Self-limited
- Green sputum doesn't mean bacterial: Can be viral
- Chest X-ray if pneumonia suspected: Fever, hypoxia, abnormal exam
- Consider PE if dyspnea with cough: D-dimer, CTA
- Pertussis: Paroxysmal cough, post-tussive vomiting
- ACE inhibitor cough: Dry, persistent, resolves with drug discontinuation
Treatment Pearls
- Antibiotics NOT for acute bronchitis: Key stewardship message
- Honey is effective for cough: Safe in adults
- Dextromethorphan for symptomatic relief: OTC antitussive
- Pneumonia: Amoxicillin, doxycycline, or azithromycin for outpatient
- Azithromycin for pertussis: Reduces transmission
- Steroids for asthma/COPD exacerbation
Disposition Pearls
- Most can be discharged: With symptomatic care
- Admit for severe pneumonia, hypoxia, or comorbidities
- Follow-up if not improving in 2-3 weeks
- Educate about antibiotics not helping viral infection
12. References
- Irwin RS, et al. Diagnosis and Management of Cough: ACCP Evidence-Based Clinical Practice Guidelines. Chest. 2006;129(1 Suppl):1S-292S.
- Kinkade S, et al. Acute Bronchitis. Am Fam Physician. 2016;94(7):560-565.
- Harris AM, et al. Appropriate Antibiotic Use for Acute Bronchitis. Ann Intern Med. 2016;164(6):425-434.
- Metlay JP, et al. Diagnosis and Treatment of Adults with Community-Acquired Pneumonia. Am J Respir Crit Care Med. 2019;200(7):e45-e67.
- Bolser DC. Cough suppressant and pharmacologic protussive therapy: ACCP evidence-based guidelines. Chest. 2006;129(1 Suppl):238S-249S.
- CDC. Pertussis (Whooping Cough). 2024.
- NICE Guideline. Cough (acute): antimicrobial prescribing. 2019.
- UpToDate. Acute bronchitis in adults. 2024.