exacerbation of asthma in children

Question 1

how would BTS classify moderate exacerbation of asthma in 1-5 year olds?

Answer 1

spo2 <92%

no clinical features of severe asthma

Question 2

how would BTS classify severe exacerbation of asthma in 1-5 year olds?

Answer 2

stats <92%

• too breathless to talk or feed
• HR >140
• RR >40/min
• use of accessory neck muscles

Question 3

how would BTS classify life threatening asthma in 1-5 year olds?

Answer 3

- <92% sats 
plus any of the following:
- silent chest 
- poor reps effort 
- agitation 
- exhaustion 
- cyanosis 
- hypotension 
- confusion

Question 4

how does BTS classify moderate exacerbation of asthma in >5s

Answer 4

<92% spo2

• PEFR >50% best
• no clinical features of severe asthma

Question 5

how does BTS classify severe exacerbation of asthma in >5s?

Answer 5

<92% spo2

• PEFR 33-50%
• HR >125
• RR >30/min
• use of accessory neck muscles

Question 6

how would BTS classify life threatening asthma in >5s?

Answer 6

<92% spo2
plus any of the following...
- PEFR <33%
- silent chest 
- poor response effort 
- agitation 
- exhaustion 
- cyanosis 
- hypotension 
- confusion

Question 7

what are the investiagations for acute exacerbation of asthma?

Answer 7

1. PEFR: dictates exacerbation severity,
2. Arterial blood gas (ABG): not routinely carried out in children but may be performed if there is evidence of a severe or life-threatening exacerbation. A low pO2 and normal or high pCO2 is worrying as it suggests exhaustion
3. Bloods: it is useful to assess for leukocytosis and raised inflammatory markers
4. CXR: may show consolidation , as well as a pneumothorax which is a complication of asthma exacerbations
5. Therapeutic trial with a beta-agonist: a positive response is suggestive of asthma

Question 8

what is the general management of an acute exacerbation of all severity?

Answer 8

1. oxygen if sats <94%
2. Inhaled salbutamol +/- ipratropium bromide:Nebulisers are indicated in moderate to life-threatening exacerbations
   Bronchodilators can be given ‘back to back’, i.e. 3 salbutamol nebulisers followed by 1 ipratropium

3.Corticosteroids:
Oral prednisolone is given if the child is alert and able to swallow, otherwise, offer IV hydrocortisone
Steroids take 4-6 hours to work and a course of 3 days is usually sufficient, but this can be extended depending on the severity

Question 9

what is the management of a severe/lifethreatening exacerbation?

Answer 9

as with general management ad if does not respond..
1. Intravenous bronchodilation: magnesium sulphate may be needed if the child does not respond

2. Other IV bronchodilators: second-line options include IV salbutamol and aminophylline
3. Ventilation: if the child is deteriorating despite the above measures, they may need non-invasive ventilation or intubation

Question 10

what is type 2 respiratory failure and why is it alarming?

Answer 10

low oxygen and high CO2

suggests exhaustion…

As the child fatigues and struggles to maintain the high respiratory rate required to ‘blow-off’ CO2, type 2 respiratory failure will occur which is very alarming and requires immediate intervention

Question 11

why is magnesium sulphate rather than IV hydrocortisone given to those suffering from life threatening asthma exacerbation?

Answer 11

Whilst it is important to administer steroids early, these take a few hours to reach maximal effect. Therefore, magnesium sulphate should be administered as a priority in order to promote bronchodilation

Question 12

what is the mechanism of action of magnesium sulphate?

Answer 12

calcium channel antagonist

Magnesium sulphate blocks the binding of calcium to smooth muscle, thereby promoting smooth muscle relaxation and bronchodilation