Basics
Description
- Croup (laryngotracheobronchitis) is a common respiratory illness in children that presents with hoarseness, a characteristic barking cough, rhinorrhea, and fever.
- Spasmodic croup (subglottic allergic edema) refers to an illness characterized by sudden inspiratory stridor at night followed by sudden resolution. Mild cold symptoms may be present but are often absent. The child can have frequent attacks on the same night or for multiple, successive nights.
Epidemiology
- Accounts for 15% of the respiratory illnesses seen in children
- Most commonly occurs in children between 6 and 36 months of age
- Although cases can be seen up to 6 years of age, it is uncommon in children older than 6 years.
- Mean age at presentation is 18 months.
- Most prevalent in the fall to early winter
- October is the most common for parainfluenza viruses.
- More common in males (ratio 1.4:1)
- ER visits for croup are most frequent between the hours of 10 p.m. and 4 a.m.
Risk Factors
- Anatomic narrowing of the airway such as in subglottic stenosis or Down syndrome
- Prior history of croup
- Hyperactive airway common in atopic children
- Preexisting airway swelling
Etiology
In children, the cricoid ring of the trachea, located in the immediate subglottic area, is the narrowest part of their upper airway. A small amount of edema in this region can lead to significant airway obstruction, which is what makes children especially susceptible to this illness. �
Caused mainly by respiratory viruses including the following: �
- Parainfluenza virus types 1-3, most commonly; accounting for 65% of cases
- Adenovirus
- RSV-in some cases, patients may also have wheezing present
- Influenza virus A, B
- Rhinoviruses
- Enteroviruses
- Metapneumovirus
- Enteric cytopathogenic human orphan virus (echovirus)
- Human coronavirus NL63
- Measles-in areas where measles is prevalent
- Mycoplasma pneumonia-associated with mild cases of croup
- Bacterial infection may occur secondarily by Staphylococcus aureus, Streptococcus pyogenes, and Streptococcus pneumoniae.
Diagnosis
History
- Croup typically starts with rhinorrhea, cough, coryza, and congestion.
- After a short period (12-48 hours), upper airway obstruction occurs resulting in hoarseness, "barky cough,"� and inspiratory stridor.
- Fever is often present.
- Symptoms persist for 3-7 days.
- Usually presents as hoarseness in children older than 6 years of age or adults.
- Recurrent episodes of stridor should lead to the consideration of spasmodic croup, an anatomic abnormality, or an underlying condition such as atopy.
- In a child with truncal or multiple strawberry hemangiomas, a sudden episode of stridor without fever or URI symptoms should raise the concern for a hemangioma in the child's airway.
- Bacterial tracheitis should be suspected in a child who develops marked worsening of symptoms with a high fever after having 5-7 days of mild croup symptoms.
Alert
The sudden development of inspiratory stridor without other upper respiratory tract infection (URI) symptoms or fever should prompt the consideration of a foreign body aspiration or upper airway mass. �
Physical Exam
- Examine the child in a comfortable position and make every effort to minimize anxiety, as this can often worsen their symptoms.
- Observe for stridor at rest, irritability, and fatigue. Assess respiratory status and level of consciousness.
- Vital signs:
- Fever and tachypnea may be present.
- A child with croup is usually not hypoxic because croup affects the upper airway.
- Hypoxia is seen only when complete airway obstruction is imminent.
- A child with croup will likely have a hoarse voice, coryza, inflamed pharynx, and varying degrees of respiratory distress.
- The degree of respiratory distress should be observed by assessing for tachypnea, nasal flaring, retractions, grunting, and use of accessory muscles.
- Children with significant upper airway obstruction may sit in a "sniffing"� position with their neck mildly flexed and head mildly extended.
- This position is in contrast to the "tripod"� position noted in epiglottitis where the child is in a sitting position with the chin pushed forward and refusing to lie down.
- The presence of inspiratory stridor should be determined.
- Stridor may be present at rest or only with agitation, and this difference will affect the patient's management.
- Stridor at rest is a sign of significant upper airway obstruction and needs urgent treatment with racemic epinephrine.
- The hydration status of the child should be assessed.
- Drooling should not be present with croup.
- Drooling may indicate a different diagnosis such as epiglottitis or peritonsillar abscess.
- The severity of croup can be determined by a clinical scoring system known as the modified Westley Croup Score (see Table 1).
- Score <3: mild disease
- Score of 3-6: moderate disease
- Score >6: severe disease
Diagnostic Tests & Interpretation
Lab
- Croup is a clinical diagnosis, and laboratory tests are not needed.
- The anxiety associated with blood draws may actually worsen the child's condition.
- Rapid antigen tests to determine the viral agent responsible for the illness may be helpful if the child has an atypical presentation or for infection control if the child requires admission.
Imaging
- Radiographs may be helpful to rule out other causes of stridor; they should be considered in children with atypical courses, recurrent episodes, failure to respond to treatment, or if a foreign body is suspected (although of note, most foreign bodies are not radio-opaque).
- Classically, an anteroposterior view demonstrates the "steeple"� sign, which is a narrowed air column in the subglottic area.
�
Table 1Croup (Laryngotracheobronchitis)-Severity Score for Croup Patients (Westley Croup Score)View LargeTable 1Croup (Laryngotracheobronchitis)-Severity Score for Croup Patients (Westley Croup Score)Indicator of Severity of IllnessScoreInspiratory stridorNone0At rest, with stethoscope1At rest, w/o stethoscope2RetractionsNone0Mild1Moderate2Severe3Air entryNormal0Decreased1Severely decreased2CyanosisNone0With agitation4At rest5Level of consciousnessNormal0Altered mental status5
Diagnostic Procedures/Surgery
- Pulse oximetry
- Visual inspection of the airway via bronchoscopy and direct or fiberoptic laryngoscopy may be helpful in cases of recurrent croup to rule out an anatomic abnormality. In spasmodic croup, noninflammatory edema may be seen of the airway suggesting atopy.
Pathologic Findings
- Gross pathology: edema and erythema of the subglottic trachea; occasionally, pseudomembranes or exudate are noted.
- Microscopic: edema of airway lining with infiltration of neutrophils, histiocytes, plasma cells, and lymphocytes
Differential Diagnosis
Other important diseases to consider in the differential include the following: �
- Infectious
- Acute epiglottitis
- Bacterial tracheitis
- Retropharyngeal abscess
- Adenotonsillitis
- Diphtheria
- Pneumonia
- Ulcerative laryngitis
- Allergic/inflammatory
- Asthma
- Anaphylaxis
- Angioedema
- Microaspiration secondary to gastroesophageal reflux or hypotonia
- Environmental
- Foreign body aspiration
- Caustic ingestion or burn
- Smoke inhalation
- Paraquat poisoning
- Traumatic
- Subglottic edema/stenosis postintubation
- Laryngeal or subglottic hematoma
- Laryngeal fracture
- Obstruction/masses
- Papillomatosis
- Hemangioma
- Cystic hygroma
- Lymphoma
- Rhabdomyosarcoma
- Thymoma
- Teratoma
- Thyroglossal duct cyst
- Branchial cleft cyst
- Congenital anomalies of the upper airway
- Tracheomalacia/laryngomalacia
- Vascular ring
- Laryngeal web
- Genetic/metabolic
Alert
Cases of epiglottitis still occur in unimmunized and underimmunized children; therefore, it is important to check the child's immunization status. �
Treatment
Initial Stabilization
- Racemic epinephrine
- Corticosteroids
- Oxygen (if needed)
- Endotracheal intubation is very rarely required, noted to occur about 1% of the time in studies.
General Measures
- Children with mild symptoms can be treated with humidity, antipyretics, and oral hydration at home. However, randomized controlled trials (RCTs) have not demonstrated a benefit for the use of humidity.
- Short, acute episodes of stridor can be treated with cool mist, a bathroom filled with steam from a shower or cold night air. If the stridor persists, worsens, or occurs at rest, the child should be seen in the emergency room.
- It is important to try to keep the child calm, as agitation or anxiety can worsen symptoms and increase work of breathing.
Alert
In the child with impending respiratory failure, prompt intubation and direct visualization of the airway in the operating room is imperative. Do not wait for x-rays to confirm a diagnosis. �
Medication
- Corticosteroids and nebulized racemic epinephrine, which are the main treatments for croup, have resulted in a dramatic reduction in the number of admissions and length of hospital stays in patients with croup.
- Dexamethasone (PO or IM; half-life 36-54 hours) 0.6 mg/kg single dose (max 10 mg) has been shown to reduce symptoms in patients with moderate to severe croup.
- Oral dexamethasone is the most cost-effective steroid treatment available.
- It has been shown to start having an effect within 30 minutes.
- Alternatively, prednisolone 1-2 mg/kg for 1-3 daily doses can be used to treat a patient with croup, although there is no RCT evidence for this method. A recent double-blinded randomized trial demonstrated that a single dose of 1 mg/kg of prednisolone was NOT as effective at keeping children from emergency medical care as 0.15 mg/kg of dexamethasone.
- Budesonide given via nebulizer at a dose of 2 mg administered q12h-shown in recent studies to be as effective as dexamethasone in reducing symptoms; less systemic absorption compared with dexamethasone, with maximum deposition of drug in the upper airway. Although widely accepted, budesonide is not as readily used as dexamethasone because it is not as cost-effective.
- Racemic epinephrine: A nebulized racemic epinephrine treatment offers immediate reduction in swelling of the laryngeal airway in children who present in extreme respiratory distress. Dose: 0.5 mL of 2.25% solution (d- and l-isomers) in 2.5 mL normal saline delivered via nebulizer as needed.
- l-epinephrine: If racemic epinephrine is not available, 5 mL of l-epinephrine 1:1,000 delivered via nebulizer is effective.
Inpatient Considerations
Admission Criteria
- Severe respiratory distress on presentation (Croup score of >3)
- Persistent hypoxia despite treatment with steroids and racemic epinephrine
- Requirement of treatment of racemic epinephrine more than once over a 3- to 4-hour period
- Dehydration or risk for dehydration
- Admission should be strongly considered for children who present symptomatically to an ER more than once and have significant stridor on day 1 of illness as croup is usually worse on days 2-3.
Discharge Criteria
- Croup score of ≤3 over a 1- to 3-hour period of observation
- Does not require racemic epinephrine in the 3-4 hours prior to discharge
- Able to take adequate PO fluids
Issues for Referral
- The vast majority of children with croup do well. However, transfer to a facility where trained individuals can address pediatric airway problems should be considered if the patient is inadequately responding to treatment or has increasing respiratory distress.
- A recent study showed heliox during transport for children with severe croup provided added benefit to their prognosis.
Prognosis
- The vast majority of patients do not require hospitalization.
- Almost all patients go on to complete recovery.
Complications
- Poor oral intake/dehydration
- Hypoxia
- Upper airway obstruction
- Respiratory failure (rare)
Ongoing Care
Follow-up Recommendations
Patient Monitoring
- In most cases, the illness is self-limited, lasting 3-5 days.
- A "rebound phenomenon"� with worsening of stridor and respiratory distress after initial relief with the racemic epinephrine treatment may be seen up to 2 hours post treatment in some patients.
- Dexamethasone has a half-life of 36-54 hours so parents should be warned that some children may have worsening in 2 days after treatment with this medication.
- Several studies have shown that children can be safely discharged 3-4 hours after racemic epinephrine treatment.
Alert
Recurrent croup may signal an underlying anatomic problem and needs evaluation for other causes. �
Additional Reading
- Bjornson �C, Russell �VF, Vandermeer �B, et al. Nebulized epinephrine for croup in children. Cochrane Database Syst Rev. 2011;16(2):CD006619. �[View Abstract]
- Cherry �JD. Clinical practice croup. N Engl J Med. 2008;358(4):384-391. �[View Abstract]
- Donaldson �D, Poleski �D, Knipple �E, et al. Intramuscular versus oral dexamethasone for the treatment of moderate-to-severe croup: a randomized, double-blind trial. Acad Emerg Med. 2003;10(1):16-21. �[View Abstract]
- Geelhoed �GC, Turner �J, Macdonald �WB. Efficacy of a small single dose of oral dexamethasone for outpatient croup: a double blind placebo controlled clinical trial. BMJ. 1996;313(7050):140-142. �[View Abstract]
- Kline-Krammes �S, Reed �C, Giuliano �JS, et al. Heliox in children with croup: a strategy to hasten improvement. Air Med J. 2012;31(3):131-137. �[View Abstract]
- Miller �EK, Gebretsadik �T, Carroll �KN, et al. Viral etiologies of infant bronchiolitis, croup and upper respiratory illness during four consecutive years. Pediatr Infect Dis J. 2013;32(9):950-955. �[View Abstract]
- Scolnik �D, Coates �AL, Stephens �D, et al. Controlled delivery of high vs low humidity vs mist therapy for croup in emergency departments: a randomized controlled trial. JAMA. 2006;295(11):1274-1280. �[View Abstract]
- Sparrow �A, Geelhoed �G. Prednisolone versus dexamethasone in croup: a randomised equivalence trial. Arch Dis Child. 2006;91(7):580-583. �[View Abstract]
- Westley �CR, Cotton �EK, Brooks �JG. Nebulized racemic epinephrine by IPPB for the treatment of croup: a double-blind study. Am J Dis Child. 1978;132(5):484-487. �[View Abstract]
Codes
ICD09
- 464.4 Croup
- 490 Bronchitis, not specified as acute or chronic
ICD10
- J05.0 Acute obstructive laryngitis [croup]
- J40 Bronchitis, not specified as acute or chronic
SNOMED
- 71186008 Croup (disorder)
- 85915003 Laryngotracheobronchitis
- 232430006 Recurrent allergic croup (disorder)
FAQ
- Q: Is humidity currently recommended for a patient presenting with croup?
- A: A RCT of mist in the emergency department setting showed no improvement in symptoms in patients with moderate croup.
- Q: Should all children with croup receive steroids?
- A: Steroids are now the 1st-line treatment for croup. Meta-analysis review strongly supports the use of dexamethasone (PO or IM) or nebulized budesonide for children with moderate to se vere croup scores. This analysis showed that steroids result in significant clinical improvement in the first 24 hours after treatment. Increasingly, studies of patients with mild croup are indicating these children may benefit from a single dose of dexamethasone.