acute bronchitis

see also:

• acute cough in the adult
• chronic bronchitis
• community acquired pneumonia (CAP) in adults

• acute bronchitis is a common cause of cough, and it is generally a diagnosis of exclusion of more serious conditions such as community acquired pneumonia (CAP) in adults
• >85% are viral and there is limited evidence that antibiotics are of use in healthy individuals

• starts as annoying dry cough with minimal fever, headache, coryzal symptoms
• may develop myalgias, fevers, fatigue
• cough generally becomes frequent enough to impair sleep
• after several days cough becomes productive of white/yellow and possibly blood-stained sputum, and lasts at least 10-14 days
• the cough lasts for less than 3 weeks in 50% of patients, but for more than 1 month in 25% of patients - especially if it is adenoviral

• exposure to irritants, such as pollution, chemicals, and tobacco smoke, may cause acute bronchial irritation
• infective causative organisms:
  • influenza virus
  • parainfluenza virus
  • human respiratory syncytial virus / human orthopneumovirus (HRSV)
  • coronavirus
  • adenovirus
  • Mycoplasma species
  • Chlamydia pneumoniae
  • Streptococcus pneumoniae
  • Moraxella catarrhalis
  • Haemophilus influenzae
  • Bordetella pertussis

• exclude serious conditions such as pneumonia, red flags include:
  • presence of complicating underlying disease such as malignancy or immune deficiency
  • SOB
  • tachycardia
  • tachypnoea
  • chest pain
  • haemoptysis
  • hypotension
  • worsening clinical state
• CXR to exclude pneumonia, etc if either:
  • HR > 100
  • RR > 24
  • oral temp > 38°C
  • chest exam suggests consolidation
• if no red flags, generally no need for blood tests, sputum cultures (sputum tests have low sensitivity and specificity), viral analysis or serology
  • adenoviral infections may cause a raised CRP thus a raised CRP does not mean it is bacterial
  • the color of the sputum has no predictive value for the diagnosis of bacterial bronchitis or the differentiation between pneumonia and bronchitis
• expectorants and antitussives are generally of no benefit
• antibiotics probably will do more harm than the potential good of reducing duration by half a day in a subgroup of patients - consider in the 1st week if high risk of it being pertussis
• beta 2 adrenergic agonists only if patient has asthma or is wheezy
• advise to abstain from smoking
• encourage fluid intake, rest, analgesics, and, nasal decongestants if blocked nose is an issue
• patients should expect the cough to last at least 10-14 days and maybe several weeks
• if the cough persists > 8 weeks then detailed investigation may be warranted