Croup

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

In mild and moderate croup, the main goals of treatment are symptomatic relief; this is achieved with supportive care and oral or nebulised corticosteroids. In moderate croup these should be combined with nebulised epinephrine (adrenaline). Children may be safely discharged home after 2 to 4 hours of observation following epinephrine administration.[37][38][39][40][41][42][43]

In severe croup, the main treatment aim is to prevent further airway compromise. In addition to the combination treatment of nebulised or parenteral corticosteroids plus nebulised epinephrine, oxygen is given to children demonstrating marked respiratory distress.[19][44][45][46][47] Intubation is indicated for impending respiratory failure.[48][49][50][51]

General care

Care should be taken to avoid frightening the child, as agitation may cause worsening of symptoms.[19] To ensure comfort, the child should be seated comfortably in the carer's lap during assessment and treatment. Although there is little research regarding the use of oxygen in croup, the clinical rationale is clear in a child with significant respiratory distress. The mechanism by which patients with severe croup become hypoxic is secondary to relative hypoventilation. Therefore, close monitoring and re-assessment should occur continuously. Humidified oxygen may be administered via a plastic hose with the opening held within a few centimetres of the nose or mouth to minimise the chance of causing agitation.[19][44][45][46][47]

Especially in mild croup, parental assurance and education to the self-limited nature of the illness is important.

Corticosteroids

Corticosteroids are the mainstay of medical treatment in mild, moderate, and severe croup.[38][52][53][54][55][56][57][58] In a systematic review, corticosteroids were found to improve symptoms of moderate to severe croup within 2 hours, with the effect lasting for at least 24 hours.[59] [ ] [Evidence C] Corticosteroid were associated with an average 15-hour reduction in length of stay in hospital or emergency department, and a 50% reduction in number of admissions for treatment and return visits.[59] However, most studies were at high or unclear risk of bias.[59]

The usual administration is a single oral dose of dexamethasone, with treatment effect evident within 2 hours, and further beneficial effects noted up to 10 hours following initial dose.[38] Traditionally, a dose of 0.6 mg/kg/dose was used for croup; however, evidence now supports the use of a smaller dose of 0.15 mg/kg/dose.[59] Adding inhaled budesonide does not appear to provide additional benefit.[60] There is inadequate evidence comparing single versus multiple doses of corticosteroids. With most croup symptoms showing resolution within 3 days of the onset, and the anti-inflammatory effect of dexamethasone thought to last between 2 to 4 days, a second dose is unlikely to be beneficial in the majority of children with croup.[61]

Both oral and intramuscular routes of administration have been shown to be equivalent or superior to inhaled corticosteroids in moderate to severe croup.[38][54][62][63][64] Alternative routes of administration will be necessary in children who do not tolerate or absorb oral medicine (e.g., children with persistent vomiting or severe respiratory distress). Inhaled budesonide may be preferable in children with severe hypoxia, in whom reduced gut and tissue perfusion can impair oral and intramuscular absorption. Establishing intravenous access can increase distress and potentially precipitate respiratory failure. Extreme care should be taken when considering intravenous administration.

To date, no adverse effects have been attributed to the use of corticosteroids in children with croup. Theoretical concerns include a possible increased risk of complications of varicella (bacterial superinfection, disseminated varicella) in a child with recent exposure.[65][66]

Adding nebulised epinephrine (adrenaline)

In moderate and severe croup, nebulised epinephrine should be administered with dexamethasone as it provides temporary relief of symptoms of airway obstruction.[67][68] A clear reduction in stridor and sternal/intercostal recession should be evident within 10 to 30 minutes following administration.[38] The clinical effects of nebulised epinephrine last on average at least 1 hour, but usually subside 2 hours after administration.[34] On average, symptoms return to their baseline, without evidence of a rebound effect.[69][34][70][71][72][73] [ ]

Although racemic epinephrine has traditionally been used to treat children with croup, L-epinephrine is as effective in moderate to severe croup.[74] In some countries, L-epinephrine availability may be limited. The same dose of nebulised epinephrine is used regardless of weight, as the effective dose of drug delivered to the airway is regulated by individual tidal volume.[75][76][77][78] No adverse effects have been noted when given one dose at a time.[74][79][69][80][81][82][83] Caution should be used with multiple doses of nebulised epinephrine.[84] There have been no reports of complications associated with the use of L-epinephrine in children with known cardiac conditions. However, careful observation is advisable if epinephrine treatment is deemed necessary.

In children who do not respond to combination treatment within a few hours following administration, a refocused assessment should take place to rule out alternate diagnoses.

Impending respiratory failure

In children progressing to asynchronous chest wall and abdominal movement, fatigue, and signs of hypoxia (pallor or cyanosis) and hypercapnia (decreased level of consciousness secondary to rising PaCO₂), endotracheal intubation may be necessary to secure the airway.

Treatments with no added benefit

Historically mist or humidified air have been widely employed, but there is now convincing evidence that these are ineffective[19][85][86][87][88][89][90] and even harmful in some instances. For example, hot humidified air carries an increased risk of scald injuries[91] and mist tents promote mould growth if improperly cleaned.[90] Additionally, being enclosed in a cold, wet space separated from the carer may increase a child's agitation.

Antibiotics, beta-2 agonists, and decongestants have not been studied and their use should be discouraged.[19][44][45][46][47]

Heliox (a defined mixture of helium and oxygen) has been studied as an adjunctive therapy in severe airway obstruction.[82][92] Helium is an inert gas that has no recognised pharmaceutical properties. Heliox usually contains 70% helium, limiting the fractional concentration of oxygen to maximal 30%. Compared with nitrogen, the major gas found in room air, the lower-density helium gas decreases the turbulence of airflow over the narrowed airways, which theoretically should result in decreased work of breathing. However, heliox has not yet been shown to confer improvements over standard therapies,[93] limits the fractional concentration of inhaled oxygen that can be provided and can be challenging to use in unskilled hands.[82][92][94][95][96][97][98][99] It is not currently recommended for use in children with severe croup.

Tracheostomy is a rare intervention reserved for cases of unsuccessful endotracheal intubation (e.g., in severe epiglottitis) and is not indicated in croup. Its complications include risk of bleeding, damage to adjacent structures in the neck, air leak (pneumomediastinum or pneumothorax), obstruction of the tracheotomy tube, infection, and tracheal injury.

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