W is for Winter.. and Wheeze: Paediatric Acute Asthma


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Author: Nikki Abela / Codes: A2 / Published: 14/11/2016

And with that comes a new season.

Just as the fashionistas have updated their wardrobes, the respiratory experts at BTS/SIGN have just produced an updated guidance to get us through the cold season.

This blog is a bit of an update and some revision of our good practice, because as Damian Roland reminds us, the child with respiratory distress is challenging, especially in those under 5 years who don’t have a formal diagnosis of asthma.

In children, intermittent wheezy episodes are usually secondary to viral infection and not necessarily combined with underlying atopy, so response to medication may be inconsistent.

At the back of your mind you should always be considering differentials such as bronchiolitis (which is more likely in the under 1s), aspiration pneumonitis, pneumonia and cystic fibrosis. Rarely, wheeze can be a sign of heart problems: LVF in babies and myocarditis in the over 1 year olds.

Remember that prematurity and low birth weight are risk factors for recurrent wheezing.

Telling the difference between viral wheeze and bronchiolitis can certainly be difficult, but don’t let it paralyse you. If unsure, it can be worth giving a child 5-10 puffs of salbutamol as a trial and having a second listen to their chest a few minutes after to see if there was any improvement. There are ways to tell the difference though, and there is a whole blog about this that might help. If you ask ten doctors about this subject, you’ll get 10 opinions!

For the purposes of this blog, we’ll talk about the acute management of asthma or viral wheeze. Thankfully you don’t need to tell these two apart in order to crack on and get acute treatment started as its the same either way. (Bronchiolitis treatment is very different).

As soon as you assess the child, try to figure out their severity score. Most EDs will have printed algorithms for a visual aid, which unless you have a mind like Sheldon Cooper, I would suggest you use.

Plan A

Give the first line treatment. This is easy enough, but I do find that I sometimes second guess myself sometimes. The BTS/SIGN guidance has answered a few of these clinical dilemmas, which I will share with you.

If the child has mild/moderate symptoms give a Salbutmol inhaler via a spacer and check their technique. Dose is not only age dependent but needs to be tailored according to symptoms so check your local protocol. Where I work it is 5 puffs in the under 5s, and 10 puffs in older children, every few or so hours according to how long they can stretch. Once they can have 5 puffs (or 10 puffs) every 3-4 hours, they can go home on this regimen and tail it down when symptoms start improving a few days down the line.

If the patient has severe or life-threatening asthma with Sats <92%, then reach for the nebulized salbutamol. If there is poor response to the first neb, then add ipratropium bromide to make a combined nebuliser which can be repeated every 20-30minutes and adjusted according to response.

Add in a steroid early in both moderate or more severe exacerbations. Hold the IV hydrocortisone for those who can’t retain oral therapy as the evidence shows that the oral and IV routes have similar efficacy.

However, do repeat the dose of steroid if it is vomited up it soon after.

Dexamethasone is starting to show some promise in replacing prednisolone, with the benefit being that it is a single dose rather than 3-day course. But the BTS/SIGN guidance advise that although the evidence is encouraging, it is still too early to make the switch.

There is also low level evidence for nebulised magnesium sulphate in the treatment of severe asthma, but BTS/SIGN say you can consider it.

OK, so youve done all that but the patient isn’t showing sign of getting better, so time to resort to plan B

Plan B

Your options now are all IV, so when giving the back-to-back nebs, put on topical anaesthetic cream in anticipation of needing a cannula and take a capillary gas measurement to check CO2 levels.

IV magnesium sulphate has the lowest side-effect profile and has been proven to work the fastest. However, most clinicians will tell you that it doesn’t always work. A wise PED consultant once told me that although there is no harm in giving it, there is harm in waiting for it to work and thereby delaying subsequent treatment. So start thinking of (and probably drawing up) your next option:

  • IV salbutamol can be given as a bolus or a continuous infusion, especially in those with refractory symptoms. Do however, check your potassium and ECG before starting treatment and have the patient on an ECG monitor.
  • IV aminophylline is usually given as a loading dose followed by a continuous infusion (omit the loading dose in those already on oral theophyllines) and place the child on an ECG monitor.

The Next Step

Critical care input is the next step for children with severe asthma not responding to treatment or with any life threatening features. There are a number of ongoing trials on the use of ketamine, sevofluorane and NIV, but the evidence is currently lacking so they’re not recommended by BTS/SIGN.

Discharge planning – When Plan A works well

Children can be discharged when stable with Sats >94% and PEF >75% on 34 hourly inhaled bronchodilators that can be continued at home.

Deciding on who can be safely discharged is easy when the child responds well to the first puffs of salbutamol. Some children who need more can be safely discharged but that decision requires experience.

Before discharge make sure you:

  • Check inhaler technique
  • Consider the need for preventer treatment or optimising/adjusting previously prescribed preventer treatments
  • Provide written advice for subsequent asthma attacks
  • Arrange follow up by a GP in two working days and refer to a paediatric asthma clinic within one to two months
  • Arrange referral to a paediatric respiratory specialist if there have been life- threatening features.

Remember: many children with recurrent episodes of wheeze triggered by viruses do not go on to develop atopic asthma.

Viral induced wheeze is not a benign illness though. Although they probably won’t benefit from steroid preventers, children still need to have good inhaler technique taught and access to salbutamol at home. Inevitably, the next attack will happen at 2am so youll see them again if they weren’t given a spray to help them stay away!

Big thanks to Edward Snelson who added much wisdom to this blog.

References/further reading:

  1. Rolobotrambles: The sounds of winter
  2. BTS/SIGN Asthma Management
  3. GP Paeds Tips: Why bronchiolitis doesn’t get better with inhalers and how understanding “why?” is better than “do that!”

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