Resp Pharmacology 3 - cough and pathophysiology

Question 1

Explain Reflex Actions - Cough

Answer 1

The cough reflex links an afferent sensory stimulus to an efferent motor response. A cough results in a forceful movement of respiratory muscles to affect the reflex.

Question 2

Cough has two roles.

Answer 2

It acts as the final pathway of mucociliary clearance and

It serves as part of the defence mechanisms against inhaled particles and noxious substances.

Question 3

Causes of cough

Answer 3

Irritants-smokes, fumes, dusts, etc.
Diseased conditions like COPD, tumors of thorax, etc.
Pressure on respiratory tracts
Infections

Question 4

Components of cough reflex

Answer 4

Cough receptors
Afferent nerves
Cough center (medulla)
Efferent nerves
Effector muscles

Question 5

Irritation

Answer 5

A stimulus irritates the upper airways and results in a reflex action leading to cough

Question 6

Inspiration:

Answer 6

Occurs to achieve optimum thoracic gas volume, thus allowing the most efficient use of the expiratory muscles

Question 7

Compression

Answer 7

With the glottis closed, the abdominal muscles and the thoracic cage actively contracts, leading to high intrathoracic pressures

Question 8

Expulsion:

Answer 8

The glottis opens and a high airflow results. The force of expression is increased by collapsing the airways following the explosive decompression caused by glottic opening

Question 9

Relaxation:

Answer 9

At the end of the cough, the intrathoracic pressure decreases as the expiratory muscles relax and a transient bronchodilatation occurs

Question 10

how to explain a type of cough?

Answer 10

dry or chesty
classified as acute, subacute or chronic

An acute cough has been present for less than three weeks and can be divided into infectious and non-infectious causes
A subacute cough resolves over three to eight weeks
Chronic, or persistent, coughs are those present for more than eight weeks

Question 11

Chronic Cough - causes

Answer 11

Environmental irritants
Conditions within the lungs
Conditions in the upper airways
Conditions within the chest cavity
Digestive causes

Question 12

Common causes of coughs within the lungs, include

Answer 12

Asthma,
COPD (emphysema and chronic bronchitis).

Question 13

Less common causes include
- cough

Answer 13

Cancer
Sarcoidosis
Diseases of the lung tissue
Congestive heart failure with chronic fluid build-up in the lungs

Question 14

Cough drugs - antitussives

Answer 14

‘Cough suppressants’
All in clinical use are opioid analgesics
Suppress cough in doses below those required for pain relief
Action is poorly defined
Suppress cough centre
Common examples
Codeine, dextromethorphan, pholcodine

Question 15

Cough drugs

Answer 15

Increase bronchial secretion or reduce its viscosity to facilitate removal by coughing

Expectorants, Secretion enhancers:

Sodium citrate, potassium iodide, guaiacol, tolu balsam, ammonium salts

Mucolytics include:

Acteylcysteine

Actively breaks disulphide bonds in mucus, thinning it

Inhaled

Mucolytics can be useful in COPD, cystic fibrosis