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Acute Bronchitis

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Overview

Acute bronchitis describes the inflammation of the bronchi, usually caused by a viral or bacterial infection.

Epidemiology

  • Most episodes of bronchitis happen during autumn or winter
  • Annual incidence is 44 per 1000 adult population

Causes

  • Viral causes are most common and may be:
    • Rhinovirus
    • Enterovirus
    • Influenza
    • Parainfluenza
    • Adenovirus
    • Respiratory syncytial virus
  • Bacterial causes may be:
    • Streptococcus pneumoniae
    • Haemophilus influenzae
    • Moraxella catarrhalis

Presentation

Acute bronchitis can be difficult to differentiate from pneumonia. Features are:

  • May or may not have sputum/wheeze/breathlessness
  • Substernal/chest wall pain may be present during coughing
  • Patients generally appear mildly ill
  • A wheeze is often present
  • Crackles are unlikely but may be present and improve with coughing
  • There is often no shortness of breath
  • Although not routinely performed for bronchitis, chest X-rays are normal

Differential Diagnoses

Community-acquired pneumonia

  • Generally more unwell and have shortness of breath, sputum, sweating, shivers, malaise etc.
  • There may be features of atypical pathogens e.g. erythema multiforme in Mycoplasma pneumonia
  • Crackles are present and usually focal

Investigations

All patients

  • None – clinical diagnosis
  • Consider chest x-ray if there is doubt:
    • In acute bronchitis, a chest x-ray is normal
  • If available, consider C-reactive protein (CRP):
    • This can be used to guide antibiotic therapy

Management

All patients

  • If stable: self-care advice + simple analgesia (paracetamol +/- NSAIDs)
  • Offer antibiotics immediately if:
    • The patient is systemically very unwell
    • They have comorbidities such as heart/lung/kidney/liver/neuromuscular disease, immunosuppression, or cystic fibrosis
    • CRP >100mg/L (offer delayed prescription if 20-100mg/L)
  • Antibiotic choices are:
    • 1st-line: doxycycline – contraindicated in children/pregnancy
      • Consider amoxicillin or if penicillin-allergic, clarithromycin or erythromycin if pregnant

Monitoring

  • Patients are not routinely followed up if they have acute bronchitis
  • If patients have worsening symptoms consider alternate diagnoses

Patient Advice

  • Acute bronchitis is usually self-limiting and the cough only lasts for 3-4 weeks, and antibiotics do not significantly change the duration of symptoms
  • Unnecessary antibiotic treatment can result in side effects such as diarrhoea/GI upset, but also can lead to increased antibiotic resistance
  • Patients should seek help if:
    • Their symptoms rapidly or significantly worsen
    • They become systemically very unwell
    • They do not improve after 3-4 weeks

Complications

  • Pneumonia – more likely in older people
  • Cough persisting for 4 weeks to 6 months (post-bronchitis syndrome)

Prognosis

  • Acute bronchitis is usually self-limiting and the cough only lasts for 3-4 weeks

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