the persistent cough

see also:

• respiratory medicine
• acute cough in the adult
• The child with a cough

• post-viral cough
• upper airway cough syndrome - usually associated with post-nasal drip
  • chronic sinusitis
  • allergic and other forms of rhinitis
• asthma
• gastro-oesophageal reflux
• chronic obstructive pulmonary disease (COPD)
• 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
• ACE inhibitor-induced cough
• cystic fibrosis
• psychogenic cough
• pertussis (whooping 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
• tuberculosis (TB)
• 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
• pulmonary embolism (PE)
• repeated aspiration pneumonitis - eg stroke patients
• lung cancer
• sarcoidosis
• 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

• 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