Cough: Mechanisms, Causes + Pharmacological Therapy

Question 1

What is a chronic cough?

Answer 1

> 8 weeks

Question 2

What does the cough reflex involve?

Answer 2

Central + peripheral mechanisms

Question 3

What is the central mechanism for a cough reflex?

Answer 3

Cough centre in medulla oblongata receives stimuli
Initiates reflex response

Question 4

What is the peripheral mechanism for a cough reflex?

Answer 4

Cough receptors in pharynx, larynx, trachea or lungs
Stimulated by air, dryness of mucous or excessive secretions

Question 5

Describe what happens when you cough

Answer 5

Cough receptor stimulated
Vagus + glossopharyngeal nerves transmit impulse to cough centre
Impulse transmitted to larynx + intercostal + abdominal muscles
Deep inspiration followed by closure of glottis, relaxation of diaphragm + contraction of muscles
Increased pressure = open glottis releases forceful expiration, cough

Question 6

What are the 3 types of cough receptors?

Answer 6

Rapidly adapting receptors (RARs)
Slowly adapting receptors (SARs)
Nociceptors on C-fibres

Question 7

Describe RARs

Answer 7

Respond to mechanical stimuli = smoke, ammonia, acidic/alkaline solutions

Question 8

Describe nociceptors on C-fibres

Answer 8

Respond to chemical stimuli = histamine, prostaglandins

Question 9

What is an example of exogenous source?

Answer 9

Smoke, dust, fumes, foreign bodies

Question 10

What is an example of endogenous origin?

Answer 10

Upper air secretions, gastric contents

Question 11

What is most common cause of chronic cough for a non-smoker?

Answer 11

Postnasal drip

Question 12

When should a cough be evaluated?

Answer 12

Chest pain
Fever
Weight loss
Blood-tinged sputum

Question 13

When is a cough productive?

Answer 13

Secretions are expectorated

Question 14

When is a cough non-productive?

Answer 14

Dry, no sputum

Question 15

What conditions are associated with dry cough?

Answer 15

Laryngitis
Smoking cough
Pneumonia
TB
Lung cancer

Question 16

What conditions are associated with wet cough?

Answer 16

Acute viral diseases
Bronchitis
Pneumonia
TB
Bronchiectatic disease

Question 17

What is a fat cough?

Answer 17

Formation of phlegm in the bronchi

Question 18

What is sputum?

Answer 18

Released during coughing process

Question 19

What is phlegm?

Answer 19

Formed in the body

Question 20

Why is phlegm produced?

Answer 20

Body wants to clear the body of foreign bodies

Question 21

What is an acute cough?

Answer 21

<3 weeks

Question 22

What is a sub-acute cough?

Answer 22

Between 3 - 8 weeks

Question 23

What are the different treatments for cough?

Answer 23

Antitussives
Expectorants
Mucolytics
Antihistamines
Bronchodilators
Pharyngeal demulcents

Question 24

What do antitussives do?

Answer 24

Supress cough by depressing cough centre

Question 25

What are examples of centrally acting antitussives?

Answer 25

Narcotics = codeine Non-narcotics = dextromethorphan

Question 26

What are examples of peripherally acting antitussives?

Answer 26

Lidocaine antihistamines SYRUPS Act on cough receptors

Question 27

What are examples of locally acting antitussives?

Answer 27

Throat lozenges, cough drops

Question 28

How do locally acting antitussives work?

Answer 28

Supress cough by increasing flow of saliva Include demulcents to decrease irritation of pharyngeal mucosa

Question 29

What are examples of oral cough suppressants?

Answer 29

Codeine + hydrocodone Dextromethorphan Diphenhydramine

Question 30

What does codeine + hydrocodone require?

Answer 30

Doctor's prescription

Question 31

Describe dextromethorphan

Answer 31

Oral cough suppressant OTC Chemically related to codeine BUT not pain-relieving

Question 32

Describe diphenhydramine

Answer 32

1st generation antihistamine = "drowsy" Recommended for night time

Question 33

How do expectorants work?

Answer 33

Increase leaking of fluid into airways Thins the thick mucus + facilitate the clearing

Question 34

Describe guaifenesin

Answer 34

Most common expectorant

Question 35

Describe mucolytics

Answer 35

Break bonds between mucus May be nebulised into face mask or mouthpiece

Question 36

What are some examples of mucolytics?

Answer 36

Sodium chloride + acetylcysteine

Question 37

What are examples of topical medications?

Answer 37

Camphor + methanol

Question 38

What do you do with topical medications?

Answer 38

Rubbed on to throat + chest as a thick layer