AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

INTRODUCTION

Section 2 of 11  

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• Clinical
• Differentials
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• Follow-up
• Miscellaneous
• Multimedia
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Background

Laryngotracheobronchitis (ie, croup) is a viral infection of the upper respiratory tract that causes varying degrees of airway obstruction.

The disease is most often self-limited, but it occasionally is severe and, rarely, fatal. A barking cough, stridor, and fever are characteristic, and it is the most common cause of stridor in children. With aggressive ED treatment, very few cases require admission.

Pathophysiology

This is a disease that mainly affects children. A prodrome of several days of fever and symptoms of mild upper respiratory infection are common.

As the infection extends to the proximal trachea, diffuse inflammation with exudate and edema of the subglottic area causes narrowing of the airway. The cricoid ring of the trachea (in the immediate subglottic area) is the narrowest portion of the airway in a child. A small amount of edema in this region can cause significant airway obstruction. (Remember that the resistance to flow through a tube is inversely proportional to the fourth power of the radius.) Air flowing through this narrowed subglottic area causes stridor. The uncomplicated disease usually wanes in 3-5 days but may persist for as many as 10 days.

Frequency

United States

Laryngotracheobronchitis has a peak incidence of 5 cases per 100 children per year during the second year of life. It is the most common form of airway obstruction or stridor in children aged 6 months to 6 years.

Mortality/Morbidity

The vast majority of children with croup do well. Morbidity is unusual, and mortality is rare.

Sex

Prevalence is higher in males than in females, with a male-to-female ratio of nearly 2:1.

Age

Illness is most common in children aged 3 months to 3 years.

• The mean age of onset is 18 months.
• Laryngotracheobronchitis is uncommon in persons older than 6 years.

CLINICAL

Section 3 of 11  

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• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

History

• The patient usually has a few days of a mild upper respiratory illness with low-grade fever, runny nose, and mild cough.
• Typically, between 6 pm and 6 am, the child develops stridor (mainly inspiratory), hoarseness, and a brassy seal-like barking cough.
• Parents may report worsening symptoms on the second night of the illness.
• The child is fatigued.

Physical

The physical examination may range from totally unremarkable on presentation to severe respiratory distress.

• Restless (common); prefers sitting upright in a parent's lap
• Appears nontoxic (common)
• Normal voice or laryngitis
• Mild fever
• Tachycardia
• Tachypnea
• Varying stridor, predominantly inspiratory
• Absence of drooling
• Retractions of the accessory chest muscles
• No change in stridor with positioning
• Nontender larynx
• Worsening disease and possible impending respiratory failure may be indicated by the following:
• • Change in mental status (eg, fatigue, listlessness, restlessness)
  • Increased retractions
  • Decreased breath sounds with decreasing stridor
  • Pallor
  • Cyanosis

Causes

Croup is most commonly caused by parainfluenza type 1, although parainfluenza type 2 and type 3 also may cause disease. Other etiologies are as follows:

• Paramyxovirus
• Influenza virus type A
• Respiratory syncytial virus (RSV)
• Adenovirus
• Rhinovirus
• Enterovirus
• Coxsackievirus
• Enteric cytopathogenic human orphan virus (ECHO virus)
• Reovirus
• Measles virus

DIFFERENTIALS

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Other Problems to be Considered

Subglottic stenosis
Retropharyngeal abscess
Subglottic hemangioma

WORKUP

Section 5 of 11  

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Lab Studies

• Laboratory testing usually is not needed in well-hydrated patients.
• If laboratory tests are needed, they should be deferred while the patient is in distress.
• Approximately 80% of admitted patients are hypoxic.
• • A pulse oximetry measurement is indicated in all but the mildest cases.
  • In the usual case, hypoxia is caused by pulmonary involvement.
  • With severe airway obstruction, respiratory failure may occur.
• Complete blood count
• • Leukopenia in early stage of illness
  • Leukocytosis in later stage of patients with severe disease

Imaging Studies

• Imaging tests are not required in mild cases with typical history that respond appropriately to treatment.
• An anteroposterior (AP) soft tissue neck radiograph may show subglottic narrowing.
• • The usual squared-shoulder appearance of the subglottic area is replaced by cone shaped narrowing just distal to the vocal cords. This is called the steeple or pencil-point sign.
  • Monitor patients during imaging because progression of airway obstruction may be rapid.

Other Tests

• Rapid antigen tests are available in some centers but usually are not needed.

Procedures

• Direct laryngoscopy if the child in not in acute distress
• Fiberoptic laryngoscopy
• Bronchoscopy

TREATMENT

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Prehospital Care

• Try to avoid actions that may agitate the child in distress and increase the work of breathing.
• Transport the child in a parent's lap and give oxygen as tolerated, usually via a "blow by" technique.

Emergency Department Care

Goals of emergency department care are to reduce any respiratory distress, monitor for worsening condition, and consider, or evaluate for, other etiologies of stridor.

• Make the child as comfortable as possible.
• Avoid agitating the child with unnecessary procedures and examinations.
• Humidified air or mist therapy may be used, but both have unproven efficacy.
• Provide oxygen (humidified) to all hypoxic patients.
• L-epinephrine (1:1000) is as effective as racemic epinephrine. Epinephrine therapy does not indicate the need for admission.
• Dexamethasone has been shown to reduce symptoms in patients with moderate-to-severe croup. (0.6 mg/kg IM, not to exceed 10 mg)
• Nebulized budesonide (2 mg) has been shown in several studies to be equivalent to oral dexamethasone. Inhaled Decadron also is used when budesonide is unavailable.

Consultations

Consultation with ORL and anesthesia prior to RSI may be necessary if patient is exhibiting rapid deterioration that might suggest an alternative diagnosis.

MEDICATION

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The goal of pharmacotherapy is to reduce morbidity and prevent complications.

Drug Category: Adrenergic agonist

Alpha-agonist effects include increased peripheral vascular resistance, reversed peripheral vasodilatation, systemic hypotension, and vascular permeability. Beta-agonist effects include bronchodilatation, chronotropic cardiac activity, and positive inotropic effects.

Drug Category: Corticosteroids

Steroids are used to decrease subglottic edema by suppressing local inflammatory process. The effectiveness of steroids in croup has been much debated, and, although no clear-cut information proves that steroids are beneficial, meta-analysis has shown that they decrease symptoms within 24 hours and may reduce the need for endotracheal intubations.

Drug Name	Prednisone (Deltasone)
Description	May decrease inflammation by reversing increased capillary permeability and suppressing PMN activity.
Pediatric Dose	1-2 mg/kg/d PO qd or divided bid for 5 d
Contraindications	Documented hypersensitivity; viral infection, peptic ulcer disease, hepatic dysfunction, connective tissue infections, and fungal or tubercular skin infections; GI disease
Interactions	Coadministration with estrogens may decrease clearance; concurrent use with digoxin, may cause digitalis toxicity secondary to hypokalemia; phenobarbital, phenytoin, and rifampin may increase metabolism of glucocorticoids (consider increasing maintenance dose); monitor for hypokalemia with coadministration of diuretics
Pregnancy	B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions	Abrupt discontinuation of glucocorticoids may cause adrenal crisis; hyperglycemia, edema, osteonecrosis, myopathy, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, myasthenia gravis, growth suppression, and infections may occur with glucocorticoid use

Drug Name	Budesonide (Pulmicort Respules inhalation suspension)
Description	Has been shown in several studies to be equivalent to oral dexamethasone.
Pediatric Dose	2 mg (2 mL of suspension) via nebulizer
Contraindications	Documented hypersensitivity; active bacterial or fungal infection
Interactions	None reported
Pregnancy	C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions	Prolonged use may increase systemic absorption of corticosteroids and may cause Cushing syndrome, reversible HPA axis suppression, hyperglycemia, and glycosuria

FOLLOW-UP

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Further Inpatient Care

• Perform frequent or continuous monitoring of respiratory status.
• Obtain a continuous pulse oximetry measurement.
• Provide a humidified environment, which may include use of the following:
• • Mist therapy
  • A croup tent (still used but generally not recommended unless no alternative therapy is available)
  • A vaporizer at bedside
• Give intravenous fluids to dehydrated children not tolerating oral fluids.

Further Outpatient Care

• Parents must provide a humidified environment at night, which may include use of the following:
• • A cool mist vaporizer
  • A steamed bathroom environment, which may relieve mild exacerbation
  • Exposure to cool night air, which may relieve mild exacerbation, especially if a spasmodic component is present
• Tobacco smoke and other irritants should not be allowed to come in contact with the child.

In/Out Patient Meds

• Inhalation of racemic epinephrine is the cornerstone of symptomatic relief during exacerbations of croup.
• Some authorities recommend a repeat dose of dexamethasone in 6 hours.

Complications

• Intubation (required in as many as 2% of patients)
• Subglottic stenosis in intubated patients
• Bacterial tracheitis
• Cardiopulmonary arrest
• Pneumonia

Prognosis

• Recovery is usually complete.

Patient Education

• For excellent patient education resources, visit eMedicine's Lung and Airway Center. Also, see eMedicine's patient education article Croup.

MISCELLANEOUS

Section 9 of 11  

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• Miscellaneous
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Medical/Legal Pitfalls

• Rebound stridor after epinephrine therapy has been described, but it appears to be less of a problem if corticosteroid therapy is initiated early in the ED course.
• Failure to treat patients with steroids can be a pitfall.
• Always consider other causes of stridor, such as foreign bodies, bacterial tracheitis, and epiglottitis.
• Failure to observe patients for an adequate period before ED discharge and failure to document satisfactory pulse oximetry.

MULTIMEDIA

Section 10 of 11  

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Media file 1:  Child with croup. Note the steeple or pencil sign of the proximal trachea evident on this anteroposterior film. Courtesy of Dr. Kelly Marshall, CHOA at Scottish Rite.
	View Full Size Image
Media type:  X-RAY

REFERENCES

Section 11 of 11

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• Bjornson CL, Klassen TP, Williamson J, et al. A randomized trial of a single dose of oral dexamethasone for mild croup. N Engl J Med. Sep 23 2004;351(13):1306-13. [Medline].
• Connors K, Gavula D, Terndrup T. The use of corticosteroids in croup: a survey. Pediatr Emerg Care. Aug 1994;10(4):197-9. [Medline].
• Dawson KP, Steinberg A, Capaldi N. The lateral radiograph of neck in laryngo-tracheo-bronchitis (croup). J Qual Clin Pract. Mar 1994;14(1):39-43. [Medline].
• Eitzen EM. Croup, epiglottis, and bacterial tracheitis. In: Rosen, ed. Emergency Medicine: Concepts and Clinical Practice. 4^th ed. 1998:1123.
• Geelhoed GC, Macdonald WB. Oral and inhaled steroids in croup: a randomized, placebo-controlled trial. Pediatr Pulmonol. Dec 1995;20(6):355-61. [Medline].
• Geelhoed GC, Macdonald WB. Oral dexamethasone in the treatment of croup: 0.15 mg/kg versus 0.3 mg/kg versus 0.6 mg/kg. Pediatr Pulmonol. Dec 1995;20(6):362-8. [Medline].
• Johnson DW, Schuh S, Koren G, Jaffee DM. Outpatient treatment of croup with nebulized dexamethasone. Arch Pediatr Adolesc Med. Apr 1996;150(4):349-55. [Medline].
• Kelley PB, Simon JE. Racemic epinephrine use in croup and disposition. Am J Emerg Med. May 1992;10(3):181-3. [Medline].
• Klassen TP, Rowe PC. Outpatient management of croup. Curr Opin Pediatr. Oct 1996;8(5):449-52. [Medline].
• Kunkel NC, Baker MD. Use of racemic epinephrine, dexamethasone, and mist in the outpatient management of croup. Pediatr Emerg Care. Jun 1996;12(3):156-9. [Medline].
• Leung AK, Kellner JD, Johnson DW. Viral croup: a current perspective. J Pediatr Health Care. Nov-Dec 2004;18(6):297-301. [Medline].
• Orenstein DM. Acute inflammatory upper airway obstruction. In: Behman, ed. Nelson Textbook of Pediatrics. 15^th ed. 1996:1201.
• Rittichier KK, Ledwith CA. Outpatient treatment of moderate croup with dexamethasone: intramuscular versus oral dosing. Pediatrics. Dec 2000;106(6):1344-8. [Medline].

Article Last Updated: Oct 1, 2007