Lecture 13-Asthma

Question 1

Define asthma

Answer 1

Chronic inflammatory disorder of the airways

Question 2

What are the five defining characteristics of asthma?

Answer 2

• chronic inflammatory process
• variable airflow obstruction
• airway hyper-responsiveness
• reversibility
• susceptibility

Question 3

Why is expiration difficult in asthmatic patients?

Answer 3

Bronchoconstriction, airway wall thickening and increased mucus secretion

Question 4

Complete the sentence: asthma is a chronic inflammatory process, driven by ___ cells which release cytokines to activate inflammatory cells (mostly ____ cells and __________). B cells are also activated and these produce Ig_

Answer 4

Th2
mast
eosinophils
E

Question 5

Describe the immediate response of exposure to the antigen causing bronchoconstriction

Answer 5

Type I hypersensitivity: interaction of allergen and IgE -> mast cell degranulation and release of histamine -> bronchoconstriction

Question 6

Describe the late phase response of exposure to the antigen causing airway inflammation

Answer 6

Type IV hypersensitivity: eosinophils, mast cells, lymphocytes and neutrophils release mediators and cytokines -> airway inflammation

Question 7

How can airway inflammation cause airway narrowing?

Answer 7

• oedema
• thickening of bronchial walls
• mucus over-production
• SM contraction

Question 8

True or false: long term, poorly controlled asthma can cause airway remodelling

Answer 8

TRUE

Question 9

Describe the major precipitating factors for asthmatic attacks

Answer 9

• allergens eg pollen, house dust mite faeces
• cold air
• exercise
• fumes
• cigarette smoke
• perfume
• stress

Question 10

When is there an increased probability that presenting symptoms are due to asthma?

Answer 10

• one or more symptoms of wheeze, SOB, cough, chest tightness
• symptoms worse at night/early morning
• symptoms vary over time and in intensity

Question 11

Why can symptoms be worse at night/early morning?

Answer 11

Higher parasympathetic tone -> bronchoconstriction

Question 12

When is there a decreased probability that presenting symptoms are due to asthma?

Answer 12

• isolated cough with no other resp symptoms
• chronic sputum production
• SOB with dizziness
• chest pain
• exercise-induced dyspnoea

Question 13

When can wheezing be absent in an asthmatic patient?

Answer 13

“Silent chest” = severe asthma exacerbations

Question 14

True or false: asthmatic patients have an increased FEV1/FVC

Answer 14

FALSE - reduced

Question 15

How does asthma present?

Answer 15

• expiratory wheeze
• cough
• diurnal variability
• difficulty breathing
• chest tightness
• exercise-induced wheeze
• atopic history

Question 16

What is the treatment plan if there is a high probability of asthma?

Answer 16

• 6 weeks inhaled corticosteroids/2 weeks prednisolone

- salbutamol (relieves symptoms but doesn’t treat inflammation)

Question 17

What is the SIMPLE treatment plan?

Answer 17

S=smoking cessation
I=inhaler technique 
M=monitor
P=pharmacotherapy
L=lifestyle changes
E=education

Question 18

When is a patient diagnosed with acute severe asthma?

Answer 18

Any one of:
-PEF 33-50%
-Resp rate more than 25/min
HR more than 110/min
-inability to complete sentences in one breath

Question 19

When is a patient diagnosed with life threatening asthma?

Answer 19

All symptoms of acute severe, plus any one of:

• altered conscious level
• exhaustion (SpO2 < 92%)
• arrhythmia
• hypotension
• cyanosis
• silent chest

Question 20

How is acute severe asthma treated?

Answer 20

• O2, high flow
• nebulised salbutamol, O2 drive
• oral prednisolone
• if the above don’t work, add nebulised ipratropium bromide and IV Mg2+