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Chronic persistent cough

Definition: ‘‘Cough is a forced expulsive manoeuvre, usually against a closed glottis and which is associated with a characteristic sound.’’ Acute cough = duration of cough < 3 weeks. Chronic cough = duration of cough > 8 weeks

History

• Age and sex – more common in middle-aged women (enhanced cough reflex)

• Patient’s description of cough (limited evidence therefore interpret with caution):

o character – honking/barking may be psychogenic/habitual

o onset – sudden may suggest foreign body

o frequency

o timing – nocturnal cough may be asthma, infection or heart failure and is less likely to be reflux.

o precipitants – enhanced cough reflex leads to triggering by temperature, scent, sprays etc. Coughing after eating after talking, laughing or singing may be reflux.

• Associated symptoms: dyspnoea, wheeze, production of sputum, extrapulmonary symptoms, stress incontinence, or systemic symptoms of fever and weight loss. If cough syncope (ask patient to inform DVLA).

• Smoking history (pack years, include questions on cannabis / shisha / water pipe / vaping) – dose dependant relationship. On quitting short term enhanced cough reflex.

• Drugs – stop ACE-inhibitors (may take months to settle).

• Occupation may be highly relevant – identification of sensitisers is important

See the BTS guidelines for example patient information leaflets, and a cough assessment questionnaire:

Cough may be the presenting symptom of an underlying disease such as asthma, COPD, bronchiectasis, lung cancer (4th most common symptom), pertussis infection, heart failure, pulmonary fibrosis or autoimmune disease. Most of these will have other associated features which will make them obvious from the history and examination.

|5 common causes of isolated chronic cough (but note may have more than one cause) |

|Gastro-oesophageal reflux |may or may not have symptoms of reflux, cough worse after eating and talking, cough |

| |disappears at night |

|Rhinitis and post-nasal drip |symptomatic nasal congestion or blockage, feeling of mucus dripping down back of throat |

|Cough-variant asthma or eosinophilic bronchitis |cough (often without symptoms of airflow obstruction) occurs particularly at night, after |

| |exercise, and after allergen/ aggravant exposure |

|ACE inhibitor (sometimes also angiotensin II receptor blocker) |important to ask about recently discontinued drugs. Can occur up to a year after |

| |initiation. Most can tolerate ARBs. |

|Idiopathic/ Post-viral |often post-menopausal middle aged women who have heightened cough reflex and previous |

| |history of preceding upper respiratory tract viral infection. Post- viral cough often |

| |disappears spontaneously after several months |

Chronic cough can be a disabling symptom associated with significantly impaired quality of life. Patients with chronic cough may report musculoskeletal chest pain, sleep disturbance and hoarse voice. The psychological impact includes a high prevalence of depressive symptoms and anxiety about possible underlying diseases such as cancer and TB.

Examination

Including:

• ENT examination - ? polyps

• SpO2 and evidence of dyspnoea or cyanosis

• wheeze (obstructive airways disease), fine end-inspiratory crackles (interstitial lung disease/fibrosis), coarse inspiratory and expiratory crackles (bronchiectasis), inspiratory squeaks (bronchiolitis or hypersensitivity pneumonitis), focal signs consistent with a structural lesion

• finger clubbing (interstitial lung disease/fibrosis, bronchiectasis, lung cancer)

Investigations for all patients:

• Chest x-ray

• Spirometry with reversibility (if obstructive deficit)

Tools for assessment of chronic cough

• Leicester cough questionnaire (well-validated cough-specific QoL questionnaire, 19 questions, includes physical, psychological and social domains. A change in score of >1.8 is deemed significant). Available at:

• Cough visual analogue scale

These tools are useful to assess patients longitudinally in clinical practice, as well as for research and audit purposes.

All other investigations should be targeted depending on likely cause(s) of cough in each case

Diagnostic/treatment approach (often occurs in parallel):

• Advise and support the patient to stop smoking – smoking is a common cause of cough (but cough reflex may be heightened in immediate short term – warn patient).

• If mass lesion on CXR, staging CT chest abdomen (with contrast) and discuss at next lung cancer MDT.

• If history and exam suggest interstitial fibrosis, HRCT thorax, lung volumes, and gas transfer.

• If bronchiectasis, HRCT thorax.

• Stop ACE-I (may take months to improve)

• Targeted treatment trials (patients should keep symptom diary during these):

o Gastro-oesophageal reflux:

▪ Mechanism may be microaspiration of gastric contnets into larynx and tracheobronchial tree, and/or vagally-mediated oesophageal reflex

▪ Stop contributory drugs if possible eg bisphosphonates, nitrates, Ca channel blockers, theophylline, progesterone

▪ Recommended 3 month acid suppression trial

▪ Omeprazole 20-40mg bd (twice daily or before meal dosing recommended)

• ± Metoclopramide 10mg tds

• ± Ranitidine 300mg nocte

▪ Consider oesophageal pH and manometry studies to rule in/ rule out gastro-oesophageal reflux and oesophageal dysmotility as causes of cough, after treatment trial

▪ Other options include: GABA-agonist baclofen which is reported to increase lower oesophageal tone. Not in widespread use. Alternatively surgery eg fundoplication may be beneficial, but timing and indications for surgery are undefined.

o Rhinitis and post-nasal drip

▪ Symptoms and clinical findings are not reliable discriminators in establishing post-nasal drip upper airways disease as a cause of cough

▪ Recommended 2-8 week treatment trial of topical nasal steroid, e.g. Mometasone 50mcg 2 sprays bd

▪ (Note that in N. America older generation antihistamines (cetirizine) are thought to be useful here)

o Cough-variant asthma/ eosinophilic bronchitis

▪ Consider bronchial provocation testing if cough-variant asthma is suspected and spirometry is normal (sequential exposure to incrementally higher dosses of methacholine to provoke a 20% fall in FEV1: normal PD20 >16mg/ml. Asthma PD20 3%) in absence of bronchial hyperreactivity provides diagnosis of eosinophilic bronchitis

o Fibreoptic bronchoscopy – principally to exclude foreign body + BAL for cell count (in idiopathic cough patients have lymphocytic airway inflammation with increased numbers of mast cells in BAL)

o HRCT chest – to exclude undetected interstitial fibrosis

o CT sinuses – if history suggestive of sinus disease

o Laryngoscopy - available in some specialist cough clinics or by ENT

o Ambulatory cough monitoring – available in come specialist cough clinics

o Bordatella pertussis swab

Treatment:

• Avoid aggravants/ precipitants

• Consider continuation and dose-optimisation of most likely helpful agents from above therapeutic trials

• Brompheniramine (sustained release) 12 mg bd

• Low dose morphine e.g. MST 5-10mg bd (opiates have a significant side effect profile which must be considered)

• Baclofen?

Idiopathic cough may be to some extent untreatable. It is important to mange patients’ expectations.

With thanks to Dr Robin Johns for the original version of this clinic aide memoire, and Prof Bothamley for additional information.

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