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 = Fractional exhaled nitric oxide: when spirometry is normal or obstructive spirometry with negative BDR test > 35 ppb
• SECOND LINE = Bronchodilator reversibility with spirometry:
  = an improvement of FEV1 > 12%
  = FEV1/FVC < 70% (obstructive)
• THIRD LINE = If Spirometry delayed then PEFR: multiple times a day over 2-4 weeks when BDR + FeNO inconclusive > 20% diurnal variation
  If asthma not confirmed by all of above, perform skin prick testing to house dust mite or measure total IgE levels and blood eosinophil count OR bronchial challenge test

Question 7

Treatment < 5 years

Answer 7

1. 8 - 12 week trial BD paediatric low-dose ICS + SABA
   Review symptoms after 3 months
2. If symptoms recur after review restart regular ICS and SABA
   Consider trial without treatment after reviewing the child with 12 months
3. LTRA + ICS + SABA for a trial of 8 to 12 weeks
   Specialist care referral

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 5-11 years old

Answer 9

1. Low dose ICS + SABA
   MART regimen
2. Paediatric low-dose MART
3. Paediatric moderate dose MART
4. Specialist referral
   If MART regimen is unsuitable - conventional pathway:
5. low dose ICS + SABA + LTRA
6. Low dose ICS + LABA (+/- LTRA if adequate response)
7. Specialist referral

Question 10

Treatment 12+ years

Answer 10

1. AIR therapy: low-dose ICS (budesonide) and formoterol
2. Low-dose MART
3. Moderate-dose MART
   *Check FeNO and blood eosinophil count:
   - If normal: moderate-dose MART +/- LTRA or LAMA
   - if raised: referral to specialist review

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%
• PEFR > 50%
• HR <140 (1-5) < 125/min (5+)
• RR < 40 (1-5 years) <30/min (5+)
  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 (OH=SHIMTE)

Answer 17

• Oxygen if SpO2 < 94%
• Salbutamol +/- Ipatropium bromide
  (SABA = FIRST LINE + ipatropium offered if needed
• Corticosteroids = Prednisolone if child alert and can swallow otherwise IV Hydrocortisone
• Magnesium Sulphate
• Theophylline/Aminophylline
• Escalate care

Question 18

Complications

Answer 18

Pneumothorax
Respiratory failure

Question 19

Medication to give on discharge

Answer 19

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