Cough

How to investigate & manage chronic cough?

Definition

  • Chronic cough is a cough lasting > 8 weeks in duration.

What are worrying "red flag" symptoms?

  • Haemoptysis (coughing up blood), unexplained weight loss, fevers, or sweats.
  • Smokers are of particular concern.
  • Chest X-rays can be falsely reassuring in these patients and they may need CT imaging.

What are key points when taking a history?

  • A full history is the key “test”, consider focusing on the list below.

Smoking history including vaping

Cough characteristics

    • Date started and tempo (better, worse, same)
    • Other respiratory symptoms - sputum, wheeze, breathlessness
    • Systemic symptoms - weight loss, fevers, sweats
    • Cough dry or productive, day or night
    • Triggers e.g. worse with change in temperature, meals, smoke, perfumes
    • Relieving factors e.g. sips of fluid, medication

Reflux symptoms

    • Ask about indigestion / heartburn, cough on immediately lying flat at night in bed while awake (before lower oesophageal sphincter closes overnight) or just on waking before out of bed (as sphincter opens) and “telephony cough” (cough worse on speaking due to diaphragmatic movement).

Exposure history

    • Home - “warm and dry” “any pets including birds” “feather or synthetic bedding” “any mould or black spots on walls”
    • Work - cough better or worse if they are on holiday, dust exposures
    • Medication - ACE inhibitors, nitrofurantoin, methotrexate
    • Hobbies

Upper airway symptoms

    • Ask about anterior / posterior nasal drip,anosmia, nasal stuffiness, sinus problems, hay fever (seasonal allergic rhinitis).

Allergy history

    • Any history of allergies including seasonal allergic rhinitis

What are the main differential diagnoses?

  • Top causes are post infection bronchial hyperresponsiveness, asthma, reflux and post nasal drip.
  • Diagnoses that are sometimes missed - lung cancer, bronchiectasis and early interstitial lung disease

What tests can be considered in Primary Care?

  • CXR
    • An early CXR is suggested e.g. in any patient with a smoking history with cough lasting 3 weeks and in any never smoker with cough lasting 8 weeks
    • The amount of radiation involved is tiny e.g. “the same amount of natural radiation that you would be exposed to by living another 3 days in your life in Grampian” or “the same amount of radiation as that experienced in a trans-Atlantic flight”.
    • A greater risk to the patient is missing a treatable condition e.g. lung cancer, interstitial lung disease.
    • Bloods
      • Full blood count - why? Elevated white cell count with neutrophilia may hint at bacterial infection, eosinophilia can hint at allergy / asthma / vasculitis, lymphopenia can hint at viral infection, sarcoidosis.
      • Allergy screen - sample to immunology asking for “Total IgE and specific IgE to common aeroallergens” - why? May hint at atopic asthma.
      • Biochemistry - why? U&Es including eGFR (latter in case patient needs a CT scan at some point with contrast), CRP (infection). Consider more extended blood tests e.g. calcium (sarcoid, malignancy), ACE (sarcoid), immunoglobulins (if recurrent respiratory tract infections to identify treatable hypogammaglobulinemia).
    • Sputum
      • If cough is productive, may identify important organisms e.g. mycobacteria, pseudomonas, which require specific treatments. Latter associated with bronchiectasis and more advanced lung disease.
  • Medication review
    • Always stop ACE-inhibitors (even if not the “primary” cause they lower cough threshold) and alternative treatments exist e.g. candesartan.
    • Nitrofurantoin - often missed, lung disease can present after years of treatment.
    • Methotrexate
    • If in doubt type drug name into www.pneumotox.com.

Top 4 causes and how to treat them?

  • General strategy: Exclude “sinister” cause of cough (detailed history, examination, tests as above + CXR) then sequential trials, each for 3 months, of treatment based on the history. Some patients of course have several causes of cough.

1. If asthma or post-infection bronchial hyperresponsiveness "twitchy airways" suspected?

  • 3 month trial
  • Very common - typically begins with infection symptoms e.g. acute onset cough, purulent sputum, malaise, fever. Patient gets better but cough persists, for several months. Eventually settles, some patients may have very mild asthma unmasked by infection, others just have post infection bronchial hyperresponsiveness (easier to term “twitchy lungs” with patients!)
  • Recovery often faster if treated with asthma medication e.g Relvar 92/22 1 puff o.d, gargling after use, with inhaler technique check.
  • Grampian inhaler guidelines on www.aberdeenlungs.com if you want to use alternatives.
  • Reinforce the fact that the inhaled steroid component will not have maximal effect until 4-6 weeks of regular use. Anecdotally by adding in a long acting bronchodilator this provides some rapid onset benefit. If prescribed only low dose beclomethasone many patients will try it for a week and then give up, since on benefit perceived.
  • If patient prefers a pressurised metered dose inhaler (pMDI) e.g Fostair always use with a spacer. Spacers doubles lung deposition - otherwise most of the drug won’t get past your patient’s tongue.
  • Review at 2-3 months. If cough is gone stop the inhaler. If cough then recurs then the patient may have asthma.


2. If reflux suspected?

  • 3 month trial
  • Omeprazole 20mg bd AND gaviscon 5mls qid
  • Rationale - Omeprazole negates gastric acid acidity but patients can still reflux neutral fluid - even if this only affects the distal oesphagus it results in neuronal activation triggering a reflex cough. An alginate such as Gaviscon acts as a floating “barrier.”
  • General advice - avoid eating late at night e.g. after 8pm, avoid foodstuffs and drinks that reduce lower oesphageal tone e.g. chocolate, cheese, caffeine, alcohol.
  • Exercise and diet to promote achieving a healthy weight.

3. If post-nasal drip suspected?

  • 3 month trial
  • Check nasal spray technique
  • Nasal corticosteroid e.g Nasonex 2 sprays each nostril once daily.+/- antihistamine e.g Dymista.
  • Nasal saline e.g NeilMed, Sterimar

4. If neurogenic cough suspected?

  • If there is no response to any of the above treatment trials then neurogenic cough should be considered.
  • 3 month trial of treatment suggested.
  • The evidence base for treatment is limited but the sorts of drugs that can be tried include
        • Nortryptiline: 10mg at bedtime increasing by 10mg each week to maximum 40mg nocte
        • Gabapentin
            • Days 1-3: 300mg at bedtime
            • Days 4-6: 300mg at lunch and bedtime (600mg total dose)
            • Days 7-9: 300mg at breakfast, mid-afternoon, bedtime (900mg total dose)
            • Days 10-12: 300mg at breakfast, lunch, dinner, bedtime (1200mg total dose)
            • If no improvement in cough after reaching 1200mg daily then probably no merit increasing further.

Who to refer to Secondary Care?

  • ‘Red flag” symptoms - haemoptysis, unexplained weight loss, fevers, sweats. Have a lower threshold of concern in patients who have a smoking history. CXRs can sometimes be falsely reassuring e.g. central lung cancer hidden behind heart, or under-reported.
  • “Red flag” signs - clubbing, persisting crackles (bronchiectasis, lung fibrosis)
  • Patients who have failed to respond to sequential trials of treatment.

What can we offer in Secondary Care?

  • Assessment in Secondary Care is often not greatly different to that which could be offered in Primary Care.
  • For selected patients we do offer CT imaging of the chest (high resolution for suspected bronchiectasis / interstitial lung disease, contrast enhanced if malignancy suspected). This can be useful (if normal, reassures patient and allows ongoing sequential trials of treatment in Primary Care).
  • CT can identify new diagnoses, most commonly bronchiectasis or lung fibrosis.
  • Bronchoscopy is rarely helpful in chronic cough patients, but is occasionally performed e.g. suspected aspiration.
  • Detailed lung function testing including assessment of bronchial hyper-responsiveness e.g. mannitol inhalation test is occasionally performed.

Useful websites / resources?