PassFinals
Respiratory

Acute Bronchitis

Acute bronchitis is a usually viral, self-limiting acute cough syndrome caused by temporary inflammation of the conducting airways; the high-yield task is to exclude pneumonia, serious illness and an exacerbation of underlying airways disease before avoiding unnecessary antibiotics.

In a nutshell

Acute bronchitis is usually a self-limiting viral acute cough syndrome. The cough may last 3 to 4 weeks. Exclude pneumonia and serious illness, do not routinely prescribe antibiotics, and use CRP thresholds only when the need for antibiotics in a lower respiratory tract infection remains unclear after clinical assessment.

Classic presentation

An otherwise well adult with a cough after a cold, perhaps with scattered wheeze or discoloured sputum, normal observations and no focal chest signs: explain the natural history, give symptomatic advice and safety-net rather than prescribing an antibiotic.

Key points

  • Acute cough associated with bronchitis usually settles within 3 to 4 weeks.
  • Coloured sputum alone does not establish bacterial infection or justify an antibiotic.
  • Focal chest signs, hypoxaemia, marked tachypnoea, confusion or systemic toxicity should prompt assessment for pneumonia or another serious illness.
  • Do not routinely offer antibiotics, bronchodilators, corticosteroids or mucolytics for uncomplicated acute bronchitis.
  • For an uncertain lower respiratory tract infection, NICE NG237 uses low, intermediate and high CRP thresholds to support no routine, back-up or immediate antibiotic decisions respectively; know the exact thresholds from the current guideline.
  • An underlying asthma or COPD exacerbation follows its own pathway; persistent or atypical cough needs cause-directed investigation.

First-line investigation

Clinical assessment with relevant observations and oxygen saturation; no routine tests for uncomplicated acute bronchitis. Use CRP only when the antibiotic decision remains uncertain after assessment, and chest imaging when pneumonia or another serious cause is suspected.

Management

Check severity and alternatives

  • Assess observations, oxygenation, focal chest signs, comorbidity and red flags for pneumonia, sepsis, pulmonary embolism or another serious diagnosis.1,2,3

Set expectations and treat symptoms

  • Explain that cough can last 3 to 4 weeks; offer self-care and appropriate symptom relief, checking BNF and product information for contraindications and interactions.1,5

Avoid routine antibiotics and ineffective medicines

  • Do not routinely prescribe an antibiotic, bronchodilator, corticosteroid or mucolytic for uncomplicated acute bronchitis; treat asthma or COPD exacerbation through its own pathway.1,6

Use CRP and escalate when concern persists

  • When a lower respiratory tract infection antibiotic decision remains uncertain, follow NG237 CRP thresholds; refer or investigate urgently when there is severe illness, hypoxaemia, focal pneumonia or another serious diagnosis.2,3

Safety-net the trajectory

  • Seek review for rapid or significant worsening, systemic illness, breathlessness, chest pain, haemoptysis or failure to improve after 3 to 4 weeks; investigate cough beyond 8 weeks or an atypical/recurrent course.1,3,4

Exam traps

  • Green or yellow sputum alone is not an indication for antibiotics.
  • A cough lasting 3 to 4 weeks can still be the expected course; worsening or red flags matter more than duration alone.
  • Focal crackles, bronchial breathing, hypoxaemia or systemic toxicity should trigger assessment for pneumonia.
  • Do not give salbutamol, corticosteroids or mucolytics routinely unless there is an underlying airways disease or another indication.
  • CRP is an aid when the antibiotic decision is uncertain after assessment, not a replacement for clinical examination or a sepsis pathway.
  • Treat a COPD or asthma exacerbation through its condition-specific pathway rather than labelling it simple bronchitis.

Key sources

  1. NICE NG120, Cough (acute): antimicrobial prescribing (Current NICE acute cough and acute bronchitis antimicrobial-prescribing recommendations, including natural history, safety-netting, antibiotic stewardship, higher-risk groups and supportive care; published 7 February 2019)Published 7 Feb 2019
  2. NICE NG237, Suspected acute respiratory infection in over 16s: assessment at first presentation and initial management (Current NICE initial assessment and CRP thresholds for suspected acute respiratory infection in people aged 16 and over; published 31 October 2023)Published 31 Oct 2023
  3. NICE NG250, Pneumonia: diagnosis and management (Current NICE adult pneumonia assessment, CRB65, referral, chest imaging, antibiotic timing and reassessment pathway; published 2 September 2025)Published 2 Sept 2025
  4. NICE CKS, Cough (NICE Clinical Knowledge Summary for assessment of acute and persistent cough; direct access may require NHS or institutional login)
  5. BNF, cough and respiratory medicines (Current UK prescribing, contraindication, interaction and patient-specific dosing reference; access may require subscription or institutional login)
  6. NICE NG115, Chronic obstructive pulmonary disease in over 16s: diagnosis and management (Current NICE COPD pathway used to distinguish and manage an infective COPD exacerbation rather than uncomplicated acute bronchitis)Published 5 Dec 2018

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.