Croup

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Laryngotracheobronchitis (croup)\: upper respiratory tract infection in children 6 months to 3 years; characteristic barking
cough, inspiratory stridor, respiratory distress.
Seasonality\: common in winter months; ranges from self-limiting to life-threatening airway obstruction.
Aetiology\: viral infection (parain
Risk factors\: age 6-36 months, family history, male gender, congenital/acquired airway narrowing, hyperactive airways.
Symptoms\: upper respiratory symptoms, fever, hoarse voice, barking cough, inspiratory stridor.
Clinical examination\: con
in severe cases.
Severity assessment\:
Mild\: no stridor at rest, barking cough, mild work of breathing.
Moderate\: stridor at rest, mild work of breathing, no agitation.
Severe\: signi
Impending respiratory failure\: reduced consciousness, fatigue, marked retractions, absent respiratory sounds, tachycardia,
cyanosis/pallor.
Di
anomalies, early Guillain-Barré syndrome.
Investigations\: clinical diagnosis; lateral airway X-ray or chest X-ray if diagnosis is unclear (steeple sign in croup).
Management\:
Mild croup\: oral dexamethasone 0.15 mg/kg, discharge with advice, follow-up.
Moderate croup\: oral dexamethasone 0.15-0.3 mg/kg, observe for improvement, discharge if stable.
Severe croup\: nebulised adrenaline, oxygen, oral or IV/IM dexamethasone 0.3-0.6 mg/kg, monitor, consider paediatric
critical care review.
Criteria for hospital admission\: severe croup, repeated adrenaline doses, toxic appearance, oxygen requirement, inability
to tolerate
Complications\: uncommon but can include secondary bacterial infections, post-obstructive pulmonary oedema,
pneumothorax, pneumomediastinum.
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Introduction

Laryngotracheobronchitis, commonly known as croup, is an upper respiratory tract infection commonly caused by a viral
infection.
Croup occurs in younger children aged 6 months to 3 years old and presents with a characteristic barking cough,
inspiratory stridor and respiratory distress.
Croup is a common presentation during the winter months. It is important to identify and treat early, as the spectrum of
disease ranges from a self-limiting illness (most common) to life-threatening upper airway obstruction.Aetiology
Croup is caused by a viral upper respiratory tract infection in
airway obstruction leading to turbulent air
The airway obstruction relates to Poiseuille’s law which states that resistance to laminar air
proportion to the fourth power of the radius. Therefore, a small reduction in airway radius (due to in
secretions) dramatically increases resistance to air
Respiratory distress is more evident when the child becomes agitated or distressed, increasing the pressure and air
through the narrowed structures.
Although croup can be caused by any respiratory virus, it is commonly caused by the parain
respiratory syncytial virus (RSV).
Croup has been seen with human coronaviruses, in
M y c o p l a s m a p n e u m o n i a e ).

Risk factors

Risk factors for croup include\:
Age\: croup most commonly occurs in children aged 6-36 months
Family history
Male (the male\:female ratio is approximately 1.4\:1)
Congenital airway narrowing
Hyperactive airways
Acquired airway narrowing

Clinical features

History
Typical symptoms of croup include\:
Upper respiratory tract symptoms including coryza and nasal congestion/discharge
Fever
Hoarse voice
Barking cough (often described as ‘seal-like’)
Inspiratory stridor
Clinical examination
Clinical examination should focus on con
should not agitate the child as this will worsen respiratory distress.
Most guidelines recommend minimal handling of the child. Throat examination is rarely required, however, if the diagnosis
is unclear, this could be considered (except in cases of suspected epiglottitis).
A rapid ABCDE assessment should be performed to identify and manage any life-threatening features, for example,
impending respiratory failure or signi
Typical clinical
Increased work of breathing\: intercostal and sternal recession
Agitation\: in severe croup
Lethargy\: in severe croup
Further examination can be performed once the situation is stabilised and no urgent treatment required. This may include
ENT examination, an examination of the cervical lymph nodes, lung auscultation and assessment for rashes.Assessment of severity
There are several validated tools used to assess the severity of croup, however, you should always refer to your local
guidelines.
One example, based on the Westley croup score, is summarised below\:
Mild croup\: no stridor at rest (may develop stridor with crying), barking cough, hoarse cry and no or mild work of
breathing (recessions).
Moderate croup\: moderate stridor at rest with mild work of breathing with little or no agitation.
Severe croup\: signi
respiratory distress including sternal recession. The child may appear anxious, pale and tired.
Impending respiratory failure\: reduced consciousness, fatigue, listlessness, marked retractions, absent respiratory
sounds, tachycardia and cyanosis/pallor.

Di

Important di
Epiglottitis\: commonly caused by H a e m o p h i l u s i n
child will appear anxious, pale and 'toxic'
. The di
typically patients sit in an upright position. Children with suspected epiglottitis should have minimal handling, do not
examine the mouth or upset the child as this may precipitate airway complete obstruction.
Upper airway abscess (such as peritonsillar, parapharyngeal and retropharyngeal)\: presents with fevers, sti
torticollis, drooling and ‘hot potato voice'
. There is an absence of the barking cough.
Foreign body inhalation\: sudden onset stridor and respiratory distress often with a history of choking. May also present
with a barking cough and stridor depending on the location of the obstruction. Importantly, there will be no fever.
Other di
bronchogenic cyst and early Guillain-Barré syndrome.

Investigations

Croup is a clinical diagnosis and does not usually require investigations.
If the diagnosis is in question and di
useful.
A chest X-ray in croup will demonstrate the steeple sign due to subglottic narrowing.
A lateral airway X-ray in children may be considered to rule out foreign body inhalation.
Figure 1. X-ray of the neck in a child with croup
demonstrating the steeple sign (narrowing of the trachea).
6Management
Croup is a self-limiting illness. Management of croup aims to reduce the severity and avoid the need for intubation.
Corticosteroids (e.g. dexamethasone) are the
Treatment depends on the severity of the presentation. It is important to follow local guidelines regarding the assessment
of croup severity and subsequent management.
Mild croup
Management of mild croup includes\:
Oral dexamethasone 0.15 mg/kg as a single dose
If otherwise well, discharge home with a written advice sheet, safety netting and early follow up in the community (within
24 hours)
Moderate croup
Management of moderate croup includes\:
Oral dexamethasone 0.15-0.3 mg/kg as a single dose
A period of observation to ensure improvement and no deterioration
Discharge criteria include no stridor at rest, normal oxygen saturations, normal colour, normal activity, able to tolerate
orally and caregivers understand when to return.
If the patient has worsened during observation, they may require nebulised adrenaline 5ml of 1\:1000 and further
observation.
Severe croup
Management of severe croup includes\:
Nebulised adrenaline 0.5ml/kg (up to 5ml) of 1\:1000 undiluted (this can be repeated if required)
Oxygen to correct hypoxia (if present)
Oral or intravenous/intramuscular dexamethasone 0.3-0.6 mg/kg
Monitoring for a minimum of four hours following a dose of adrenaline, due to the risk of rebound of symptoms after the
adrenaline wears o
If children with severe croup require two or more doses of adrenaline, consider paediatric critical care review. An early
review by the intensive care team is important as the patient may require intubation to protect the airway.
Criteria for hospital admission
Indications for hospital admission include\:
Severe croup
Moderate to severe croup but with deterioration or repeated doses of adrenaline
Toxic appearing child
Oxygen requirement
Inability to tolerate oral
Additional factors to consider include young age, number of healthcare attendances, carer anxiety or an inability for carers
to bring the child back to the hospital in case of deterioration.

Complications

In most children, croup resolves within three days.
Complications are uncommon but can include\:
Secondary bacterial infections (including bacterial tracheitis, bronchopneumonia and pneumonia)
Post-obstructive pulmonary oedema
PneumothoraxPneumomediastinum

References

UpToDate, Woods, Charles R. C r o u p \: C l i n i c a l f e a t u r e s , e v a l u a t i o n , a n d d i a gn o s i s . Jun 15, 2018. Available from\: [LINK]
UpToDate, Woods, Charles R. M a n a g e m e n t o f C r o u p . Oct 16, 2019. Available from\: [LINK]
Maloney, E. and Meakin, G., 2007. Acute stridor in children. C o n t i n u i n g E d u c a t i o n i n A n a e s t h e s i a C r i t i c a l C a r e & P a i n , 7(6),
pp.183-186.
NSW Health. C h i l d r e n a n d I n f a n t s - A c u t e M a n a ge m e n t o f C r o u p . 25 August 2017.
The Royal Childrens Hospital Melbourne. C r o u p . Available from\: [LINK]
Radiopaedia / Assoc Prof Craig Hacking and Assoc Prof Frank Gaillard. S t e e p l e S i g n . License\: [CC-BY-NC]. Available from\:
[LINK]
BMJ Best Practice. C r o u p . Updated April 2020. Available from\: [LINK]
NICE Clinical Knowledge Summary. C r o u p . 2017. Available from\: [LINK]
Oxford Handbook of Paediatrics. O x f o r d H a n d b o o k o f P a e d i a t r i c s . 2008.
Bjornson CL, Johnson DW. C r o u p . The Lancet. 2008.
Foster S. N H S G G & C G u i d e l i n e s - E m e r g e n c y M e d i c i n e - C r o u p . Available from\: [LINK]

Reviewer

Dr Thuy-Tien Vo
Paediatric Registrar
Dr Louise Lawrence
Paediatric Registrar

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Contents

Introduction
Aetiology
Risk factors
Clinical featuresSource\: geekymedics.com