It’s 0200 hours in the Emergency Department, and you hear a seal …
As children have returned to school, we have seen more croup through the ED, so it’s time to refresh your memories!
What is croup?
Viral laryngotracheobronchitis. It is essentially inflammation around the main large breathing structures, usually caused by parainfluenza 1 + 3. Other respiratory viruses, including SARS-CoV-2 and RSV, may also be involved. This inflammation causes a tell-tale cough and noisy breathing due to the obstruction to flow. There may also be signs of increased work of breathing, such as sub-costal recession or a tracheal tug. However, they are generally quite well and are running around the waiting room!
Who gets croup?
Many children – roughly 2-3% of all children per year! These kids are usually between six months and four years of age and occur at the beginning of autumn, though this spring, we see a lot of cases. Children with croup may present with a preceding coryza-like illness and a low-grade fever. This then develops into a barking “seal-like” cough and, for some reason, always seems worse at night. Boys are more commonly affected than girls; some children get it yearly.
How do we treat croup?
This depends on your assessment of the child. Croup is a self-limiting viral illness, and treatment tends to look to a short-term reduction in inflammation to improve the work of breathing. Historically clinicians have used the Westley scoring system to score croup and assess their severity before giving medication.
In children who look unwell, it is important to not upset them by avoiding unnecessary interventions such as excessive handling or performing an ENT exam.
The Role of Steroids in Croup
If the child can take the medication, dexamethasone or prednisolone should be given to all cases of croup where any stridor or increased effort in breathing is present.
Dexamethasone appears to be more efficacious than prednisolone. It has an onset of action within 1 hour (30 minutes – 4 hours) and has a half-life of up to 36-72 hours (Schimmer 2005). There has been debate over dosing with doses of 0.15mg/kg, 0.3mg/kg and 0.6mg/kg of dexamethasone. Ultimately, 0.15mg/kg is not inferior to 0.6mg/kg. At the time of writing, NICE and the BNFc recommend 0.15mg/kg as the initial dose of dexamethasone. If there are concerns about re-occurrence, patients are occasionally sent home with an additional dose to be taken 12 hours later.
Prednisolone tends to be favoured in primary care at a 1mg/kg dose with two additional daily doses. There appears to be no significant clinical difference between the two different steroids regarding the need for further treatment or length of stay. Dexamethasone was associated with a reduction in re-attendances, which may be due to the shorter half-life of Prednisolone (Gates 2018, Schimmer 2005)
Nebulised budesonide (2mg stat dose) is reserved for children who cannot take oral medication. This may be because it was spat out or because they are working too hard to breathe. A Cochrane review in 2018 shows that budesonide is not superior to dexamethasone, with Westley Croup scores better in the dexamethasone group at 6 and 12 hours compared to budesonide. A combination of treatments does not appear to lead to additional benefits (Gates 2018)
The Role of Adrenaline/Epinephrine in Croup
In severe cases, when the child has features of severe work of breathing, including significant recession, hypoxia or tiring, nebulised adrenaline has been used (0.4-0.5ml/kg, maximum 5ml of 1:1000). Adrenaline provides short-term relief from respiratory distress. It can be a bridge to getting steroids on board. The effects are short-acting and wear off after a couple of hours. It can be repeated every 30 minutes, although if you need repeat doses, anaesthetics and senior colleagues should be involved in this patient’s care.
What doesn’t work in Croup?
In the olden days, parents tried treating croup at home with steam inhalation (ineffective). In hospitals, humidified oxygen has also been tested though this has not been proven effective (Moore 2007). Heliox (oxygen and helium combined) has also been looked at as it may improve airflow. However, the evidence is limited, and safety and efficacy remain questionable (More, 2018). Finally, there is no evidence that salbutamol works for croup.
They sound better; what’s next?
Patients can be discharged home with safety-netting advice if they are well and the stridor has resolved. The effects of dexamethasone should last as croup itself is usually limited to 2-3 days of symptoms. However, parents need to be aware that some symptoms of respiratory distress can return, usually the following night.
Patients may require a prolonged period of observation if:
- stridor is still present at rest, or there is increased work of breathing
- the child is very young (<3 months)
- an adrenaline nebuliser had to be given
- there is a past history of severe croup
- there is a history of upper airway problems (i.e. laryngomalacia or subglottic stenosis)
- concerns about the child returning (i.e. long-distance, social concerns)
When is it not croup?
- Epiglottitis – a rare condition thanks to the HiB vaccine. A child would present with sudden onset, fever, drooling and looks unwell, holding the head back and neck extended. This is a medical emergency, and keeping the patient calm is paramount.
- Tracheitis– thankfully also rare. It presents with the child acutely unwell after a prolonged course similar to Croup.
- Anaphylaxis/allergy – this may be accompanied by angioedema, rash and wheeze and requires swift treatment with IM adrenaline.
- Quinsy/retropharyngeal abscess
- Foreign body – Usually, the history would help suggest this, with a sudden onset history in a well-child.
COVID and croup
Most children admitted into hospitals are now swabbed for COVID. This can provide a challenge – balancing upsetting the child (and making the upper airway obstruction worse) and performing an invasive swab. It is sensible not to swab the child whilst there is still concern about acute stridor and work of breathing.
Some case studies suggest that a small cohort of patients with croup who were SARS-CoV-2 positive are less responsive to the usual treatment (Venn 2020). These cases may need prolonged admission due to a lack of response and the need for additional supportive therapy.
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Venn AMR, Schmidt JM, Mullan PC. A case series of pediatric croup with COVID-19 [published online ahead of print, 2020 Sep 15]. Am J Emerg Med. 2020;S0735-6757(20)30829-9. doi:10.1016/j.ajem.2020.09.034