Asthma

Question 1

Asthma

Answer 1

chronic respiratory condition characterised by recurrent episodes of airflow obstructions, bronchial hyperresponsiveness, and underlying inflammation

Question 2

Aetiology of asthma

Answer 2

• genetics (FHx.)
• environment (allergens, air pollution)
• infections (viral URTIs)
• sensitisation and atopy (eczema, rhinitis, food allergies)
• sociodemographics (lower status, rural vs. urban)
• lifestyle (diet and exercise)

Question 3

Risk factors for asthma

Answer 3

• personal or FHx. of atopy
• antenatal exposure (smoking)
• low birthweight
• not breastfed
• high allergen exposure
• high air pollution
• the ‘hygeine hypothesis’

Question 4

Pathophysiology of asthma

Answer 4

1. airflow obstruction (smooth muscle contraction by mast cells, eosinophils)
2. mucous hypersecretion
3. bronchial inflammation (from IgE dependent mast cell degranulation)
4. ** airway hyperresponsiveness**
5. airway remodelling

Question 5

Symptoms of asthma

Answer 5

Cough:
- nocturnal
- dry
- non-productive

SOB:
- exercise
- cold air
- allergens

Question 6

Clinical signs of asthma

Answer 6

Wheeze:
- expiratory
- polyphonic

Increased work of breathing:
- tachypnoea
- accessory muscle use
- head bobbing
- nasal flaring

In severe exacerbations:
- altered mental status
- silent chest
- cannot finish sentences
- significant tachycardia
- exhaustion

Question 7

Investigating suspected asthma

Answer 7

1. Spirometry with bronchodilator reversibility
2. FeNO levels
3. Peak expiratory flow diary

Question 8

Spirometry results in asthma

Answer 8

• > 5 years old
• FEV1/FVC ratio < 70% (obstructive)
• Bronchodilator reversibility +ve

Question 9

Results of bronchodilator reversibility test in asthma

For 5-16 years & > 16 years

Answer 9

5-16:
- increase > 12% FVC

> 16:
- increase > 12% FVC
- increase > 200ml volume

Question 10

FeNO results in asthma

For 5-16 years & 16+ years

Answer 10

5-16:
- FeNO > 35

16+:
- FeNO > 40

Question 11

Peak flow findings in asthma

when measured for 2-4 weeks

Answer 11

more than 20% variability

Question 12

Differentials for asthma in children

Answer 12

• ciral induced wheeze
• bronchiolitis
• inhaled foreign body
• cystic fibrosis
• structural airway disease (e.g. bronchomalacia)

Question 13

Stepwise treatment ladder in asthma

Answer 13

1. SABA
2. SABA + low-dose ICS
3. SABA + low-dose ICS + LTRA (montelukast)
4. SABA + low-dose ICS +/- LTRA + LABA
5. SABA +/- LTRA + MART
6. SABA +/- LTRA + medium-dose MART
7. SABA +/- LTRA + high-dose ICS or theophylline

Question 14

MART Regimen in Asthma

Answer 14

• Maintenance & reliever therapy
• Form of combined ICS and LABA

Question 15

Complications of asthma

Answer 15

• status asthmaticus
• pneumonia
• COPD
• pneumothorax
• airway remodelling
• osteoporosis (long term steroids)
• anxiety and depression (living with chronic disease)

Question 16

Managing mild-moderate asthma exacerbation

Answer 16

First line:
- SABA 4-10 puffs/20mins
- oral corticosteroid

Consider:
- inhaled anticholinergic (ipratropium)
- controlled O2
- antibiotics

Question 17

Managing a severe exacerbation of asthma

Answer 17

First line:
- Hospital admission
- Nebulised SABA
- Oral/parenteral corticosteroid
- Controlled O2

Second line:
- Nebulised anticholingeric (ipratropium)
- Nebulised Magnesium sulfate
- IV salbutamol

Third line:
- antibiotics
- IM adrenaline
- Ventilation

Question 18

Managing a life-threatening exacerbation of asthma

Answer 18

First line:
- ICU admission
- Nebulised salbutamol
- Oral/parenteral corticosteroid
- Controlled O2

Second line:
- nebulised anticholinergic (ipratropium)
- nebulised magnesium sulfate
- IV salbutamol

Third line:
- antibiotics
- IM adrenaline
- ventilation

Question 19

Drugs used in asthma exacerbations

Answer 19

• salbutamol (inhaled, nebulised, IV)
• corticosteroids (oral, parenteral)
• ipratropium (nebulised)
• magnesium sulfate (nebulised)

Question 20

Discharge criteria for asthma exacerbation

Answer 20

• Stable on SABA every 3-4 hours
• Peak flow > 75% of best/predicted
• O2 sats > 94% in room air

Question 21

Clinical features of mild/moderate asthma exacerbation

Answer 21

• SpO2 > 92%
• RR < 30
• No or minimal accessory muscle use
• Talking in full sentences
• Wheeze (may only be audible with stethoscope)

Question 22

Clinical features of severe asthma exacerbation

Answer 22

• SpO2 < 92%
• PEFR 33-50% predicted
• RR > 30
• Can’t finish sentences
• HR > 125
• Use of accessory muscles
• Audible wheeze

Question 23

Clinical features of life threatening asthma exacerbation

Answer 23

• SpO2 < 92%
• PEFR < 33% predicted
• Silent chest
• Poor respiratory effort
• Altered consciousness
• Agitated/confused
• Exhaustion
• Cyanosis