Asthma

Question 1

Define bronchial asthma.

Answer 1

A chronic inflammatory disorder characterised by hyperreactive airways, airway inflammation and reversible airflow obstruction leading to episodic reversible bronchoconstriction

Question 2

What are the different kind of asthma?

Answer 2

Extrinsic (atopic) - response to inhaled antigen
Intrinsic (non-atopic) - non-immune mechanisms (cold weather, exercise, drugs)
Multifactorial - bit of both

Question 3

What kind of hypersensitivity is asthma?

Answer 3

Type 1

Question 4

What happens in asthma?

Answer 4

Allergen binds to IgE on mast cell and degranulation occurs. Histamine is released with other inflammatory markers.

Question 5

What do histamine and the other inflammatory markers cause?

Answer 5

• muscle spasm - bronchoconstriction (wheeze)
• mucosal inflammation - mucosal oedema and increased secretions (sputum)
• inflam cell infiltrate - infiltration of lymphocytes and eosinophils (yellow sputum)

Question 6

Give some pathological features of asthma.

Answer 6

Narrowed oedematous airways
Mucus plugs – secretions are increased
Inflammatory cells (lymphocytes, plasma cells, eosinophils)
Epithelial cell damage

Question 7

When does asthma present in life?

Answer 7

early or late onset

Question 8

What is the clinical syndrome of asthma?

Answer 8

• episodic signs and symptoms
• diurnal variation
• non-productive cough
• wheeze
• shortness of breath
• chest tightness
• associated atopy (hayfever, eczema, conjunctivitis)
  FH of asthma or atopy

Question 9

How is a diagnosis of asthma made?

Answer 9

• suspicion must be gained from history before preceding to tests
• PEFR (2x daily monitoring for obvioouos diurnal variation)
• Spirometry - obstructive pattern then >15% improvement in FEV1 or PEF following inhaled salbutamol
• Exercise tests - diagnose asthma in children

Question 10

What is the treatment for an acute exacerbation of asthma?

Answer 10

• Oxygen
• Salbutamol nebulised high dose
• Hydrocortisone IV (or oral if can take orally)
• Ipratropium bromide nebulised
• Magnesium IV
• Theophylline IV
• Anaesthetist

Question 11

What is step 1 of the BTS asthma guideline?

Answer 11

Avoidance of allergen!
Inhaled Salbutamol PRN
if using twice i one week then step up

Question 12

What is step 2 of the BTS asthma guideline?

Answer 12

Add inhaled corticosteroid beclometasone

Question 13

What is step 3 of the BTS asthma guideline?

Answer 13

Add LABA inhaled Salmeterol

Question 14

What is step 4 of the BTS asthma guideline?

Answer 14

Add leukotriene receptor anatgonist Montelukast, or ora theophylline or oral B2 agonist

Question 15

What is step 5 of the BTS asthma guideline?

Answer 15

Add regular oral steroid Prednisolone

Question 16

What is step 6 of the BTS asthma guideline?

Answer 16

Refer to asthma clinic

They may give Omalizumab (suppresses mast cell degranulation response to allergens)

Question 17

How do B2 adrenoceptor agonists work?

Give 2 examples of this drug

Answer 17

Salbutamol and Salmeterol
increase cAMP to relax bronchial smooth muscle within minutes
increase mucous clearance & decreased inflam mediator release from mast cells & neutrphills

Question 18

How do corticosteroids work?

Give 2 examples of this drug

Answer 18

Beclometasone and Prednisolone

• Decrease formation of Th2 cytokines and cause apoptosis
• prevent production of IgE antibodies
• prevent allergen induced influx into lung and cause apoptosis
• reduce number of mast cells and decrease Fce expression

Question 19

How do Xanthines work?

Give an example of this drug

Answer 19

inhibit phosphodiesterase leading to decreased bronchoconstriction and increased cAMP levels

Question 20

What do Xanthines have that require something to be done about it?

Answer 20

Narrow therapeutic index

blood test required 4-6hours after infusion started

Question 21

How do cysteinyl leukotriene receptor antagonists work?

Give an example of this drug

Answer 21

Montelukast
anatgonise CystLT1 receptor, blocking the effects of cysteinyl leukotrienes in the airways therefore relaxing bronchial smooth muscle

Question 22

How does airway smooth muscle remodel in asthma?

Answer 22

undergoes hypertrophy and hyperplasia leading to a larger fraction of the wall being occupied by smooth muscle tissue. The deposition of repair collagens and matrix proteins below the basement membrane further thickens the airway wall.

Question 23

Which drugs can cause the wheeze in asthma?

Answer 23

NSAIDs
Aspirin
B-blockers

Question 24

Which drug is absolutely contraindicated in a patient with asthma?

Answer 24

B-blocker

Question 25

Patients with acute severe asthma typically have what?

Answer 25

inability to complete a sentence in one breath
RR > 25 breaths per min
HR >110bpm
PEFR 33-50% of predicted

Question 26

Features of life threatening asthma.

Answer 26

Silent chest, cyanosis, feeble respiratory effort
exhaustion, altered conscious level
bradycardia or hypotension
PaO2 <33% predicted

Question 27

What is the initial treatment of acute severe asthma?

Answer 27

salbutamol by oxygen driven nebuliser

Question 28

When is exercise induced asthma maximal?

Answer 28

5-10 minutes after the end of exercise