Chronic cough in Adults
Questionnaire/history:
Cough for over 8 weeks?
Cough hypersensitivity: Laryngeal paraesthesia/irritation? Dry cough to innocuous stimuli (e.g. talking, eating, enviroment irritans such as fumes, change in air temperature)?
(Note: Many have underlying hypersensitivity of the cough reflex, which in then exacerbated by contributing traits, such as infections, airways inflammation, smoking, obstructive sleep apnoea, etc. with increasing evidence that underlying hypersensitivity is due to dysregulation of the neuronal pathways controlling cough and that chronic cough could be considered a neuropathic disorder.)
Treatable traits: Airways disease (asthma, COPD)? Gastro-oesophageal reflux? (Note: Most trials of PPI do not improve cough, heartburn has the strongest association, but the response rate to PPIs is still low at 28%) Chronic rhinosinusitis? - Symptoms/signs of nasal blockage? (Note: BTS report 'doubt' about post-nasal drip as a cause of chronic cough, but it may be a symptoms of chronic rhinosinusitis (CRS))
Obstructive sleep apnea? (Note: Commonly associated with chronic cough, may enhance cough hypersensitivity, unknown whether CPAP helps.) Obesity? Smoking? ACE inhibitors? Inducible laryngeal obstruction?
Anxiety? Low mood?
Complications: Cough syncope? Stress urinary incontinence? (Note: affecting 30-50% of females with chronic cough) Examination:
Chest auscultation?
Investigations: FBC? Chest X-ray? Spirometry? FeNO (if available)? Blood eosinophil count? Sputum culture if infection suspected?
Pertussis serology?
Diagnosis:
Suspected cough hypersensitivity (if aggravants are excluded and treatable traits are optimally managed but chronic cough continuous, which may be the issue when no other cause if found, but may also co-exist with other treatable traits)?
(Note: Most common in middle-aged females)
Management:
Suspected cough hypersensitivity:
Non-pharmacological: - Sipping water - Honey - Speech and language therapy - Physiotherapy
Pharmacological:
Low-dose slow-release morphine - 5mg bd (max. 10mg bd, no benefit of going higher) - 50% of patient report benefit within 5 days (symptoms return quickly on cessation - Tolerance does not appear to develop, but obvious concerns regarding addiction/abuse - Codeine not advised due to 'variable and unpredictable metabolism'
Gabapentin: - 100mg tds initially, max 600mg tds - Improved cough-specific OoL in a single RCT - Side effects common Amitriptyline: - Uncertainty over its benefit Baclofen: - Limited use due to side effects Novel therapies: - Focus on the P2X3 sensory nerve receptor, which causes vagal airway nerve activation, linked to the cough reflex
Referral: Diagnosis unclear?
Cough continues despite treatment?
Suspected serious underlying disease (e.g. bronchiectasis, TB)?
Ref flags (urgent, 2 week-wait):
≥ 40yo in ex- or current smoker, or previous history of asbestos?
Associated chest pain or systemic features (e.g. weight loss, fever)?
Recurrent/persistent chest infection?
Persistent hoarseness or concerning dysphagia symptoms?
Haemoptysis?
Resource(s):