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the persistent cough

the adult with a persistent cough

differential diagnosis

  • post-viral cough
  • upper airway cough syndrome - usually associated with post-nasal drip
    • chronic sinusitis
    • allergic and other forms of rhinitis
  • chronic bronchitis, cigarette smoking
  • bronchiectasis - usually substantial sputum
    • HRCT is 84-96% sensitive in detecting bronchiectasis, helical MDCT with thin collimation is more sensitive than HRCT but has higher radiation dose and should be avoided in young adults, particularly females.1)
  • non-asthmatic eosinophilic bronchitis (NAEB) - responds well to inhaled steroids
  • hypersensitivity pneumonitis
    • eg. from humidifiers or aerosolized water contaminated with thermophilic actinomycetes, Sphaeropsidales, Penicillium sp, and Klebsiella oxytoca
  • cystic fibrosis
  • psychogenic cough
    • ~20% of adults with unexplained persistent cough - particularly during 3-5 year epidemic cycle
    • as with asthma and inhaled FB, it generally worsens at night
    • may last 12 months with exacerbations during intercurrent viral URTI's.
  • Chlamydia pneumoniae - ~20% of adults with unexplained persistent cough 2)
    • usually sputum is scant, but headaches and hoarseness are often prominent, rhonchi are usually present and the cough may last months
  • cardiac failure
  • Lady Windermere Syndrome - non-TB mycobacteria infecting R middle or L. lingula lobes, mainly in middle aged or elderly thin women who avoid expectorating for social reasons and fail to clear the sputum.
  • Hot Tub Syndrome - non-TB mycobacteria creating hypersensitivity pneumonitis picture
    • most have diffuse infiltrates on CXR and ground glass opacities on HRCT usually with nodular opacities
  • repeated aspiration pneumonitis - eg stroke patients
  • tracheo-oesophageal fistula
  • Zenker diverticulum
  • Wegener's granulomatosis
  • interstitial lung disease
  • inhaled foreign body
  • pulmonary histoplasmosis - fungal infection from inhaled soil contaminated with bird or bat droppings

Mx in ED

  • good history - smoking, sputum, blood, PE risk factors, nocturnal worsening, LOW, possible TB exposure, IVDU, HIV risk, etc
  • examination - wheeze, sinuses, pharynx, cardiac failure, DVT, clubbing, SaO2, etc
  • CXR - if lesion, may need CT scan
  • if rhinitis/sinusitis the likely cause, Rx appropriately and cease vasoconstrictors which may be causing vasomotor rhinitis
  • outpatient trial of inhaled steroids may help undiagnosed asthma or NAEB
  • cough medicines will NOT work and only cause side effects
  • antibiotics are unlikely to be helpful in the chronic phase, even if it is pertussis
  • refer to GP for ongoing Ix and Mx as needed
    • if above fail, consider referral to ENT or for lung function testing / respiratory medicine as appriopriate
Acad Emerg Med 4(3):179, March 1997
cough_persistent.txt · Last modified: 2017/03/09 14:49 by

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