Asthma

Question 1

What is asthma?

Answer 1

An allergic disorder mediated by IgE in response to an allergen/trigger eg pollen, exercise

Question 2

What causes bronchospasm in patients with asthma?

Answer 2

IgE causes an inflammatory response, histamine, prostaglandins, leukotrines and eosinophils enter the airway, goblet cells over produce mucous and T-lymphocytes release cytokines to potentiate the inflammatory response. This cascade causes bronchospasm.

Question 3

How is asthma diagnosed?

Answer 3

There is no single test to diagnose asthma. Use lung function tests based on predicted values based on age, race, sex and height. Expect asthma patients to have a decreased PEFR and FEV1 but it should improve after a SABA or corticosteroid.

Question 4

What does an FEV1/FVC ratio below 70% indicate?

Answer 4

Obstruction

Question 5

How much should FEV1 improve by in asthma patients after they have taken salbutamol?

Answer 5

400ml

Question 6

Give 3 examples of inhaled corticosteroids.

Answer 6

Beclomethasone, budesonide, ciclesonide.

Question 7

List the ADRs for inhales corticosteroids.

Answer 7

Oral thrush, adrenal suppression and hoarseness

Question 8

When are corticosteroids indicated in asthma patients?

Answer 8

If the patient has had an exacerbation in less than 2 years, is using their beta 2 agonist more than 3x a week, is waking 1 night a week and is symptomatic more than 3x a week.

Question 9

When is IV hydrocortisone used in the treatment of asthma?

Answer 9

In acute severe situations

Question 10

What is the dose and duration for prednisolone for an acute asthma attack?

Answer 10

40-50mg for 5 days

Question 11

List the ADRs for prednisolone.

Answer 11

Hyperglycaemia, moon face, acne, skin thinning, osteoporosis, adrenal suppression, hypertension.

Question 12

Give two examples of long acting beta 2 agonists.

Answer 12

Salmeterol and formoterol

Question 13

What is the duration of action for a LABA?

Answer 13

12 hours

Question 14

What is the onset and duration of action for a SABA?

Answer 14

1-5min onset, 4-6 hour duration

Question 15

What is the mechanism of action for beta 2 agonists?

Answer 15

Relax airway smooth muscle by stimulating beta 2 receptors which increase cAMP and prevent bronchoconstriction.

Question 16

What are the side effects of beta 2 agonists?

Answer 16

Tremor, nervous tension, hypokalaemia, headache, tachycardia, peripheral vasodilation.

Question 17

How is inhaled medication classified?

Answer 17

Relievers- quick symptomatic relief when required eg SABA
Preventers- act on underlying inflammation eg corticosteroids
Controllers- eg LABA

Question 18

Give an example of a leukotrine antagonist.

Answer 18

Montelukast

Question 19

What is the mechanism of action of leukotrine antagonists?

Answer 19

Antagonise bronchoconstriction, airway oedema and mucous production.

Question 20

Give 3 side effects of montelukast

Answer 20

Sleep disturbances, rash and thirst

Question 21

What are cromones?

Answer 21

Mast cell stabilisers

Question 22

Which patients are cromones used for?

Answer 22

5-12 year olds

Question 23

What is the mechanism of action of cromones?

Answer 23

Inhibit histamine release from mast cells

Question 24

What are methylxanthines?

Answer 24

Phosphodiesterase inhibitors that inhibit leukotrine synthesis and thus inflammation and bronchodilation.

Question 25

Give an example of a methylxanthine.

Answer 25

Theophylline

Question 26

Why do methylxanthines have many interactions and ADRs?

Answer 26

Because they are metabolised by CYP450

Question 27

Why must the brand of methylxanthines used in a specific patient remain constant?

Answer 27

Because they have a narrow therapeutic index.

Question 28

True or false, smoking and alcohol can lead to a sub therapeutic dose of theophylline?

Answer 28

True

Question 29

What are anti IgE monoclonal antibodies licensed for?

Answer 29

Adults and children over 12 for severe persistent allergic asthma

Question 30

How are ant IgE monoclonal antibodies administered?

Answer 30

By a subcutaneous injection every 2-4 weeks

Question 31

What is the mechanism of action of anti IgE monoclonal antibodies?

Answer 31

Inhibit binding of IgE to mast cell receptors to prevent the inflammatory response.

Question 32

How should you monitor a patient with asthma?

Answer 32

O2 sats (aim= 94-98%), PEF, CRP, WCC, blood pH (due to risk of acidosis), hydration, serum K+ (because hypokalaemia is a side effect of beta agonists), theophylline levels, tachycardia, arterial blood gasses.

Question 33

How do severe/life threatening exacerbation of asthma present?

Answer 33

With cyanosis, drowsiness, difficulty speaking, unconsciousness, tachycardia and severe dyspnoea.

Question 34

What can be given in acute asthma if the patient has a PEF of less than 50%?

Answer 34

A single dose of IV magnesium sulphate as it is a smooth muscle relaxant

Question 35

Define acute asthma

Answer 35

Respiratory rate of more than 25 breaths/minute, heart rate of more than 110bpm, O2 sats less than 92%