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Pediatrics, Croup or Laryngotracheobronchitis

Author: Lonnie King, MD, Consulting Staff, Department of Emergency Medicine, Children's Healthcare of Atlanta at Scottish Rite
Contributor Information and Disclosures

Updated: Aug 11, 2009

Introduction

Background

Laryngotracheobronchitis (ie, croup) is a viral infection of the upper respiratory tract that causes varying degrees of airway obstruction.1

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.

Child with croup. Note the steeple or pencil sign...

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.

Child with croup. Note the steeple or pencil sign...

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.

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

History

  • The patient with laryngotracheobronchitis (ie, croup) 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:

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References

References

  1. Johnson DW. Croup. Clin Evid (Online). Mar 10 2009;2009:[Medline].

  2. [Guideline] Mazza D, Wilkinson F, Turner T, Harris C. Evidence based guideline for the management of croup. Aust Fam Physician. Jun 2008;37(6 Spec No):14-20. [Medline].

  3. 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].

  4. Connors K, Gavula D, Terndrup T. The use of corticosteroids in croup: a survey. Pediatr Emerg Care. Aug 1994;10(4):197-9. [Medline].

  5. 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].

  6. Eitzen EM. Croup, epiglottis, and bacterial tracheitis. In: Rosen, ed. Emergency Medicine: Concepts and Clinical Practice. 4th ed. 1998:1123.

  7. Geelhoed GC, Macdonald WB. Oral and inhaled steroids in croup: a randomized, placebo-controlled trial. Pediatr Pulmonol. Dec 1995;20(6):355-61. [Medline].

  8. 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].

  9. 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].

  10. Kelley PB, Simon JE. Racemic epinephrine use in croup and disposition. Am J Emerg Med. May 1992;10(3):181-3. [Medline].

  11. Klassen TP, Rowe PC. Outpatient management of croup. Curr Opin Pediatr. Oct 1996;8(5):449-52. [Medline].

  12. 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].

  13. Leung AK, Kellner JD, Johnson DW. Viral croup: a current perspective. J Pediatr Health Care. Nov-Dec 2004;18(6):297-301. [Medline].

  14. Orenstein DM. Acute inflammatory upper airway obstruction. In: Behman, ed. Nelson Textbook of Pediatrics. 15th ed. 1996:1201.

  15. Rittichier KK, Ledwith CA. Outpatient treatment of moderate croup with dexamethasone: intramuscular versus oral dosing. Pediatrics. Dec 2000;106(6):1344-8. [Medline].

Further Reading

Keywords

croup, laryngotracheobronchitis, viral infection of the upper respiratory tract, airway obstruction, parainfluenza type 1, parainfluenza type 2, parainfluenza type 3, upper respiratory infection, URI, paramyxovirus, influenza virus type A, respiratory syncytial virus, RSV, adenovirus, rhinovirus, enterovirus, coxsackievirus, enteric cytopathogenic human orphan virus, ECHO virus, reovirus, measles virus, barking cough, viral infection

Contributor Information and Disclosures

Author

Lonnie King, MD, Consulting Staff, Department of Emergency Medicine, Children's Healthcare of Atlanta at Scottish Rite
Lonnie King, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, and American College of Emergency Physicians
Disclosure: Nothing to disclose.

Medical Editor

Jerry Balentine, DO, Professor of Emergency Medicine, New York College of Osteopathic Medicine; Executive Vice President, Chief Medical Officer, Attending Physician in Department of Emergency Medicine, St. Barnabas Hospital
Jerry Balentine, DO is a member of the following medical societies: American College of Emergency Physicians, American College of Osteopathic Emergency Physicians, American College of Physician Executives, American Osteopathic Association, and New York Academy of Medicine
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from financial planner; Avanir Pharma Stock Investment from financial planner ; WebMD Salary and stock Employment and investment from financial planner

Managing Editor

Wayne Wolfram, MD, MPH, Clinical Associate Professor, Departments of Pediatrics, Children's Hospital and University of Cincinnati
Wayne Wolfram, MD, MPH is a member of the following medical societies: American Academy of Emergency Medicine, American Academy of Pediatrics, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Richard G Bachur, MD, Associate Professor of Pediatrics, Harvard Medical School; Associate Chief and Fellowship Director, Attending Physician, Division of Emergency Medicine, Children's Hospital of Boston
Richard G Bachur, MD is a member of the following medical societies: American Academy of Pediatrics, Society for Academic Emergency Medicine, and Society for Pediatric Research
Disclosure: Nothing to disclose.

 
 
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