Croup is characterised by the abrupt onset, most commonly at night, of a barking cough, inspiratory stridor, hoarseness, and respiratory distress due to upper airway obstruction. It leads to signs of upper airway obstruction, and must be differentiated from acute epiglottitis, bacterial tracheitis, or an inhaled foreign body. Croup affects about 3% of children a year, usually between the ages of 6 months and 3 years, and 75% of infections are caused by parainfluenza virus. Symptoms usually resolve within 48 hours, but severe infection can, rarely, lead to pneumonia, and to respiratory failure and arrest.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments in children with: mild croup; moderate to severe croup; and impending respiratory failure because of severe croup? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2008 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
We found 43 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
In this systematic review we present information relating to the effectiveness and safety of the following interventions: antibiotics, corticosteroids, dexamethasone (intramuscular, oral, single-dose oral, route of administration), heliox, humidification, intermittent positive pressure breathing, L-adrenaline, nebulised adrenaline (epinephrine), nebulised budesonide, nebulised short-acting beta2 agonists, oral decongestants, oral prednisolone, oxygen, and sedatives.
Croup leads to signs of upper airway obstruction, and must be differentiated from acute epiglottitis, bacterial tracheitis, or an inhaled foreign body.
Croup affects about 3% of children a year, usually between the ages of 6 months and 3 years, and 75% of infections are caused by parainfluenza virus.Symptoms usually resolve within 48 hours, but severe infection can, rarely, lead to respiratory failure and arrest.
A single oral dose of dexamethasone improves symptoms in children with mild croup, compared with placebo.
Although humidification and oral decongestants are often used in children with mild to moderate croup, there is no evidence to support their use in clinical practice.There is consensus that antibiotics do not improve symptoms in croup of any severity, as croup is usually viral in origin.
In children with moderate to severe croup, intramuscular or oral dexamethasone,
nebulised adrenaline (epinephrine), and nebulised budesonide reduce symptoms compared with placebo.
Oxygen is standard treatment in children with respiratory distress. Oral dexamethasone is as effective as nebulised budesonide at reducing symptoms, and is less distressing for the child.A dexamethasone dose of 0.15 mg/kg may be as effective as a dose of 0.6 mg/kg. Adding nebulised budesonide to oral dexamethasone does not seem to improve efficacy compared with either drug alone.Nebulised adrenaline (epinephrine) has a short-term effect on symptoms of croup, but we don't know whether adding intermittent positive-pressure breathing to nebulised adrenaline further improves symptoms.We don't know whether heliox (helium–oxygen mixture), humidification, short-acting nebulised beta2 agonists, or oral decongestants are beneficial in children with moderate to severe croup, or with impending respiratory failure.
In children with impending respiratory failure caused by severe croup, nebulised adrenaline (epinephrine) is considered likely to be beneficial. Oxygen is standard treatment.
Nasogastric prednisolone reduces the need for, or duration of, intubation, but sedatives and antibiotics are unlikely to be beneficial.