Chronic cough

Paul Tan MD, FRACP

Consultant Physician

Department of Medicine, KTPH

Disclaimer

• Acute, sub-acute and chronic cough

• General approach to cough (with a focus on chronic cough)

• Common causes of chronic cough – ACE induced cough

– Upper airway cough syndrome

– Asthma/Eosinophillic bronchitis

– GORD

• Antitussives

Acute cough (<3weeks)

ACCP 2006

Subacute cough (3-8 weeks)

ACCP 2006

Chronic cough >8 weeks

ACCP 2006

Some red flags:

• Unwell, septic

• Weight loss

• Night sweats

• Haemoptysis

• Foreign body inhalation

Chronic cough

• ACE induced cough

• UACS

• Cough variant asthma/NAEB

• GORD

ACE induced cough

• Common, between 5-20% • Usually within 2 weeks of ACE exposure,

sometimes can be delayed up to 6 months • Mechanism not fully understood, probably to do

with the kinins, substance P both of which metabolizes via converting enzymes

• Regardless of how long patients have been on ACE, if presents with chronic cough, should discontinue and replace either with an ARB / different class of anti hypertensives. (NICE)

• ARBs can cause chronic cough, approximately 5%

Upper airway cough syndrome

• Previously known as post nasal drip syndrome • Now includes: allergic rhinitis, vasomotor rhinitis,

rhinosinusitis • Consider allergy panel • Trial of treatment

– Antihistamines/decongestants – Nasal steroids – Response usually in days/ short weeks, but trial for a

month if response continue for 3 months (A/D) – If persistent sinus symptoms but no response to cough

• Sinus imaging vs ENT (Rhinosinusitis) • Role of empiric therapy?

Cough variant asthma/NAEB

• Isolated cough without objective evidence of asthma variable airflow obstruction. Approximately 30% of chronic coughs

• Cough variant asthma: – Cough; nocturnal, with exercise or triggers – Usually normal or near normal PFT – Usually positive broncho provocation test (MCT)

• NAEB – No bronchial hyperresponsiveness (MCT negative) – Sputum eosinophilia

• Treatment options: – ICS (No evidence for LABA) – LTRAs

GORD

• About 5-41%

• Consider eliminating medications that can worsen GORD

– Bisphosphanates, nitrates, calcium channel blockers, theophyllines, progesterones

• High dose PPI, alternatively H2 blockers.

• 8 week trial

What do I do?

History, physical and CXR NAD. Not on ACE-I. Non smoker. No

red flags

Assess severity. Subjective, patient perception. Cough

incontinence, sleep disturbances etc

Treat as silent reflux/GORD: High dose omeprazole 40mg BD. Minimum for 2 months.

Assess response in 2 months

Pre and post spirometry

MCT challenge same visit if possible

Start ICS

Review response in 2 months

Allergy panel

Refer ENT for nasendoscopy

Treat sinus disease.

Antihistamines/decongestants

Nasal steroids

Review 1 month

CT sinus and HRCT

Review 2 weeks with results. Discuss need for bronchoscopy

Reassess severity of symptoms. Is it truly troublesome cough?

Are invasive investigations justified?

Bronchoscope

24 hour esophageal pH monitoring for non acid reflux

Review with results

Endoscopy +/- manometry Speech therapist/ video fluoroscopy/ swallow assessment BNP, 2DE/ Cardiac investigations

Antitussives

Old wife’s remedy

Dextrometorphan Codeine Morphine Gabapentin

Atrovent

Robitussin/ Guaifenesin Difflam Antihistamines Lignocaine

Lung cancer & chronic cough

• Lung cancer accounts for 2% of chronic coughs

– Usually haemoptysis, weight loss, smoker, localized wheeze, abnormal chest x rays

• Irwin RS, Chronic cough. The spectrum and frequency of causes, key components of the diagnostic evaluation, and outcome of specific therapyAm Rev Respir Dis. 1990;141(3):640.

• But, chronic cough is present in >65% patients with lung cancer

• ACCP 2006

CT lung screening

• National Lung Screening Team

• 55-74 years old, 30 pack years smoker (if ex, stopped within the last 15 years.

• Excluded previous lung cancer diagnosis, CT in the last 18 months, weight loss, hemoptysis.

• 26722 annual low dose CT for 3 years vs 26732 annual chest x ray for 3 years

55-74 years old, 30 pack years smoker (if ex, stopped within the

last 15 years.

Excluded previous lung cancer diagnosis, CT in the last 18

months, weight loss, hemoptysis.

26722 annual low dose CT for 3 years

247 deaths from lung cancer/ 100000 patient years

6467 “positive” 20255 “negative”

26732 annual chest x ray for 3 years

309 deaths from lung cancer per 100000 patient years

1845 “positive” 24887 “negative”

UKLS position statement

1) The feasibility and cost effectiveness of CT screening in the UK; 2) Defining who is likely to benefit most from CT screening; 3) Harmonising the CT acquisition technique, scan reading protocols and acceptable performance levels in the participating centres; 4) Determining the value of the individual work-up techniques for suspicious findings and standardisation of performance; 5) Determining the optimal surgical management of patients with screen-detected nodules; 6) Establishing the optimal screening interval and the number of screening rounds for both screen-negative and screen-positive individuals.

My take home:

• Chronic cough >8 weeks, replace ACE-I, stop smoking & CXR

• Look out for red flags

• Sequential investigations and treatment

• In general, low likelihood lung cancer

• Difficult to apply US or even UK recommendations in Singapore; higher prevalence of infectious disease such as TB