Assessment of chronic cough in adults

Question 1

What is a cough?

Answer 1

A forced expulsive manoeuvre, usually against a closed glottis, associated with a characteristic sound

Question 2

What is ‘cough reflex (CR)’?

Answer 2

A primary defence mechanism:
oSpecialised epithelial barriers
oImmune responses
oNeural reflex responses (e.g. cough)
•Lungs open to atmosphere
•Shared portion with passage of foods

Question 3

Where is the cough receptor located?

Answer 3

Located mainly in posterior wall of the trachea, pharynx & carina of the trachea

Question 4

What are the afferent nerve fibres?

Answer 4

Mechanosensors and chemosensors

Question 5

what is the difference between mechanosensors and chemosensors?

Answer 5

Mechanosensors readily activated by mechanical stimuli, e.g.–Lung inflation–Bronchospasm
-Generally do not respond to chemical stimuli

Chemosensors (nociceptors)
•Activated directly by chemicals, e.g.:–Capsaicin, Bradykinin
Located in airways and lungs
•Types include C-Fibres

Question 6

What is an acute cough? and what are some of the symptoms associated with an acute cough?

Answer 6

•A cough lasting < 3 weeks

• Haemoptysis
• fever
• dyspnoea

Question 7

What does the term ‘chronic cough’ mean?

Answer 7

•A cough lasting > 8 weeks
oPaediatrics – daily cough lasting > 4 weeks (ACCP)

•Significant sputum production may suggest primary lung pathology

Question 8

What are the possible common causes of ‘chronic cough’?

Answer 8

• Age/Gender – more common in middle aged women
• Infection
• Asthma / other lung disorders (e.g. bronchitis, IPF etc)
• Allergy
• Tobacco smoking (dose-related)
• Obesity

Question 9

What is ‘ACE inhibitors’?

Answer 9

It is Angiotensin Converting Enzyme, which is a medication used to treat patients with hypertension/ heart failure.

Question 10

How does ACE inhibitors affect coughing?

Answer 10

Around 20% of patients on ACE inhibitors develop a dry cough.
-The cough is thought to be linked to the suppression of ACE.

•Cough suppresses after discontinuation of medication:
oUsually within 4 weeks

Question 11

How should a chronic cough be diagnosed?

Answer 11

• History taking
• Chest X-RAY should be performed in all patients with CC
• Spirometry should be performed in all patients with CC
• Bronchodilator assessment (if airflow obstruction present)

Question 12

What further diagnostic test(s) can be performed?

Answer 12

Bronchial provocation testing: e.g. methacholine, histamine

induced sputum analysis

Oesophageal manometry