Sign or symptom Mild Moderate or severe Stridor None or only if agitated Stridor at rest Respiratory rate Usually normal May be decreased Retractions None + to +++ Air entry Normal Normal to decreased Colour Normal May be pallor Cyanosis None Late sign only Conscious state Normal Restless or decreased

After Marks et al 2003.²

Most children with mild croup are not distressed and have only a barking cough with no stridor at rest or stridor audible only with physical activity, crying, or agitation. Crying causes physiological narrowing of the airway and will increase the respiratory distress. Hence the distressed, crying child’s obstruction will often defervesce by allowing the child to be cuddled in the parent’s arms. There may be signs due to viral illness, such as mild fever and nasal discharge. Children with mild cases can have their throats examined, but this should be deferred in more severe cases. A compromised but functioning airway should never be made worse by upsetting the child.

In more severe cases, the child may have a more pronounced stridor at rest. As airway obstruction progresses, increased work of breathing ensues and the child exhibits increasing substernal, intercostal, and subcostal retractions. Subtle signs of hypoxia causing altered consciousness may be reflected as anxiety or restlessness in a child. An obviously fatiguing child is a worrying sign. The child manifesting decreased air entry and respiratory effort, extreme pallor, and cyanosis requires immediate intervention.

The child’s preferred position may also give clues as to severity of obstruction or to a diagnosis other than croup. Hyperextension or other abnormal positioning of the neck may suggest epiglottitis or a retropharyngeal abscess. It is unusual for the child with croup to be saliva intolerant or have any tenderness of the neck.

The use of a croup severity score may be helpful for less-experienced staff to assess children with croup and communicate findings with a colleague when seeking advice. As previously mentioned, some children may have concomitant wheeze in addition to the upper airway stridor and hence their pattern of breathing may be ‘gas trapped’ and cause hyperinflation of the chest with slow expiration phase, in contrast to those with pure croup alone.

Investigations

Croup is usually an easy ‘spot diagnosis’ and requires no diagnostic tests.

Oximetry is of limited value, as children may maintain near-normal oxygen saturations even when they have significant airway obstruction.³ While it may have a role in cases of severe croup, this must be balanced with the distress caused by the monitoring probe in small children. In stable cases, where the diagnosis is unclear, a lateral soft tissue X-ray of the neck may be helpful to distinguish croup from epiglottitis or retropharyngeal abscess. However, the possible benefits of an X-ray need to be weighed against the risks of moving or disturbing the child when the obstruction is more than mild. A nasopharyngeal aspirate in croup is not necessary for diagnosis but may be useful for infection control for patients being admitted.

Differential diagnosis

It is important to establish that other, more sinister, causes of acute upper respiratory tract obstruction masquerading as croup are not present (Table 6.7.2). Especially in the younger child, one should enquire regarding longer-term symptoms preceding the present episode, such as low-grade stridor. This might suggest underlying congenital airway or vascular anomaly (e.g. tracheomalacia, subglottic stenosis, bilateral cord paralysis, laryngeal web, or vascular ring compression of the trachea). One should also enquire as to possible airway trauma or toxic ingestion. Dysphagia and drooling may suggest epiglottitis, peritonsillar or retropharyngeal abscess, or foreign body in the airway or oesophagus.

• Epiglottitis

• Bacterial tracheitis

• Foreign body

• Congenital: laryngomalacia, subglottic stenosis, vascular ring, cord paresis

• Retropharyngeal abscess

• Allergic oedema

• Airway trauma

Classic croup and epiglottitis are hard to confuse, as the latter usually presents as a pale, toxic, drooling child with a rapidly progressing course. Cough is generally not a prominent feature in epiglottitis. Children with epiglottitis may sit forwards, drooling saliva, and hold their neck in extension. In a child presenting with early epiglottitis, however, the distinction may be more difficult. Immunisation in developed countries, however, has made this distinction largely academic. Allergic angio-oedema may mimic croup after exposure to an allergen such as peanut. A child with ‘severe croup’ with a high fever, who does not respond to adrenaline (epinephrine) and steroids, may have tracheitis and will need consideration of a diagnostic laryngoscopy to provide a clear diagnosis. Likewise, the possibility of an inhaled foreign body should be kept in mind for children who don’t respond to treatment or have a prolonged course. While usually parents will volunteer a history of an acute obstruction or a sudden coughing fit, the history of an inhaled object may not always have been observed and therefore reported. A definitive diagnosis may need to be made by directly viewing the upper airway, but this should be performed only by an experienced paediatric anaesthetist, intensivist, or emergency physician in an appropriate clinical setting (see below).

Treatment and disposition

Mild or moderate croup

All children who present to an emergency department with croup should be treated with steroids.⁴ The mandatory use of steroids for croup in emergency departments results in a reduction in the relapse rate of those sent home,⁵ the average length of stay in hospital falling, and the number of children needing intensive care and intubation dramatically reducing.^6,⁷ Prior to the regular use of steroids, a general rule of thumb was to admit children with stridor at rest (moderate) to hospital for observation, while allowing those with occasional stridor and barking cough only (mild) to be managed at home. As many children will improve within a few hours of taking steroids, often they may be discharged home after a short stay in the emergency department or an observation ward. Factors such as the distance from medical care, the availability of transport, the time of day, the child’s past history with regard to severe airway obstruction, and parental concern and attitude all need to be taken into account when making the decision to admit (Table 6.7.3).

• Upper airway obstruction at rest: fails to respond to steroids or adrenaline (epinephrine) and period of observation (4 hours)

• Severe croup or moderate croup that does not respond to treatment

• Infants <6 months

• Previous severe croup

• Underlying airway problem

• Inadequate social factors i.e. transport or lack of follow up

• Recurrent presentation

Recommended steroid doses are oral dexamethasone in a one-off dose of 0.15 mg kg^–1,⁸ or an equivalent dose of prednisolone of 0.75 mg kg^–1. Most children with croup will require only one dose, but if the upper airway obstruction symptoms persist (as opposed to upper respiratory tract infection symptoms), a further dose may be given 18 to 24 hours later. It is often more convenient to use prednisolone (rounded off to 1 mg kg^–1) in the community, as it is more readily available. While one study⁹ suggested that children treated with prednisolone may re-present more commonly than those treated with dexamethasone, Fifoot et al¹⁰ did not confirm this finding. Steroids may be administered intramuscularly or intravenously in the child with severe obstruction, when there is concern that the child may aspirate or vomit, given their degree of respiratory difficulty.

Oral dexamethasone has been found to be as effective as inhaled steroids such as budesonide,¹¹ and to work as fast, at a fraction of the cost. A blinded randomised trial, submitted for publication, of dexamethasone 0.15 mg kg^–1 compared to placebo that looked at croup scores at 10-minute intervals after administration showed a significant difference at 30 minutes.¹² Combining dexamethasone and budesonide is no more effective than dexamethasone alone.^11,¹³ There is no place for antibiotics in a typical case of croup. The use of ‘steam’ or humidified air is unproven,^14,¹⁵ despite its once common usage. The anecdotal report by parents of their child improving in the steam-filled bathroom at home is due to the defervescing of crying which occurs from cuddling in the room by the parent, rather than any steam effect.