Resp - Asthma

Question 1

Definition

Answer 1

Type 1 hypersensitivity reaction = Reversible paroxysmal constriction of the airways with inflammatory exudate and followed by airway remodelling
Most chronic condition of children

Question 2

Epidemiology and risk factors

Answer 2

• Genetic
• Prematurity
• Low birth weight
• Parental smoking
• Viral bronchiolitis in early life
• Cold air
• Allergen exposure e.g. dust
• Bottle fed

Question 3

Signs

Answer 3

• Diurnal peak expiratory flow rate (PEFR) variation
• Dyspnoea and wheeze

Question 4

Symptoms

Answer 4

• Episodic shortness of breath
• Dry cough
• Wheeze and ‘chest tightness’
• Features of atopic disease e.g. eczema

Question 5

Diagnosis < 5 years

Answer 5

Based on clinical judgement with regular reviews
- Perform tests once child reaches 5 years old

Question 6

Diagnosis 5-16 years

Answer 6

FIRST LINE = Spirometry: FEV1/FVC < 70% (obstructive)
Bronchodilator reversibility = an improvement of FEV1 > 12%
Fractional exhaled nitric oxide: when spirometry is normal or obstructive spirometry with negative BDR test > 35 ppl
PEFR: multiple times a day over 2-4 weeks when BDR + FeNO inconclusive > 20% diurnal variation

Question 7

Treatment < 5 years

Answer 7

1. SABA
2. (Not controlled on 1. OR newly diagnosed with Sx > 3 weeks OR night time waking)
   SABA + trial paediatric moderate dose ICS for 8 weeks
   - If Sx do not improve during trial consider alternative Dx
   - If Sx resolve but recur within 4 weeks of stopping trial: restart paediatric low-dose ICS
   - If symptoms resolved but recur beyond 4 weeks stopping trial: repeat 8 week trial of paediatric moderate dose ICS
3. SABA + paediatric low dose ICS + LTRA
4. Stop LTRA and seek expert opinion

Question 8

Paediatric dosing of ICS

Answer 8

Low dose < 200 micrograms budesonide
Moderate dose 200-400 micrograms budesonide
High dose > 400 micrograms budesonide

Question 9

Treatment 5-16 years old

Answer 9

1. SABA
2. SABA + paediatric low dose ICS
3. SABA + paediatric low dose ICS + LTRA
4. SABA + paediatric low dose ICS + LABA + consider stopping LTRA
5. SABA + switch ICS/LABA to MART
6. SABA + moderate dose ICS + MART
   OR SABA + moderate dose ICS + LABA
7. SABA + (one of the following)
   - Increase ICS to paediatric high dose (fixed dose or MART)
   - Trial additionally agent e.g. Theophylline
   - Seek expert opinion

Question 10

Complications

Answer 10

• Asthma exacerbation
• Pneumothorax

Question 11

Asthma exacerbation

Answer 11

Airway bronchospasm and an inflammatory response leading to muscosal oedema and secretion
This results in obstruction of the bronchioles leading to increased work of breathing in order to maintain adequate oxygenation

Question 12

Triggers

Answer 12

• Viral infection
• Inhaled allergen
• Exercise
• History of atopy : such as eczema or allergic rhinitis
• Medications : particularly NSAIDs and non-cardioselective beta-blockers

Question 13

Moderate clinical features

Answer 13

SpO2 > 92%
No clinical features of severe asthma

Question 14

Severe clinical features

Answer 14

Any one of:
- SpO 2 < 92%
- PEFR 33-50% predicted
- Can’t complete sentences in one breath
- Too breathless to talk or feed
- Heart rate > 140 (1-5 years)
- Heart rate > 125 (>5 years)
- Respiratory rate > 40 (1-5 years)
- Respiratory rate > 30 (>5 years)

Question 15

Life threatening clinical features

Answer 15

Any one of the following in a child with severe asthma:
- SpO 2 < 92%
- PEFR < 33% predicted
- Silent chest
- Poor respiratory effort
- Agitation
- Exhaustion
- Cyanosis
- Hypotension
- Confusion

Question 16

Diagnosis

Answer 16

FIRST LINE = PEFR <33% of predicted suggestive of a life-threatening attack
ABG: low pO2 and normal or high pCO2 is worrying as it suggests exhaustion
Bloods
CXR: shows consolidation if the exacerbation is triggered by infection, as well as a pneumothorax = complication of asthma exacerbations

Question 17

Treatment for all severities

Answer 17

• Oxygen if SpO2 < 94%
• Inhaled salbutamol +/- ipatropium bromide
  (SABA = FIRST LINE + ipatropium offered if needed)
• Corticosteroids
  = Prednisolone if child alert and can swallow otherwise ofdter IV hydrocortisone
  = Course of 3 days usually sufficient

Question 18

Treatment for life threatening exacerbation

Answer 18

FIRST LINE = IV bronchodilation = magnesium sulphate
SECOND LINE = IV salbutamol and aminophylline
Finally if all else fails ventilation or intubation

Question 19

Complications

Answer 19

Pneumothorax
Respiratory failure

Question 20

Medication to give on discharge

Answer 20

Oral prednisolone 30-40mg for 3-5 days and GP follow up for 48 hours