croup. sindrome

8/13/2019 Croup. Sindrome

http://slidepdf.com/reader/full/croup-sindrome 1/8

PEDIATRIC ANNALS 39:1 | JANUARY 2010 www.PediatricSuperSite.com | 15

Croup: Common Syndromes and Therapy

Diseases resulting in airway com-

promise are the leading cause of

cardiac arrest in children.1 The

narrowest portion of the pediatric airway

(in those younger than 10 years) is at the

level of the cricoid cartilage, termed the

subglottis, just below the vocal cords.

This anatomic feature makes children

more susceptible to airway obstruction

from infectious diseases than adults.

1. Delineate the differential diagnosisof croup in children.

2. Review the clinical evidence support-ing the use of nebulized epineph-rine for croup in the emergencydepartment, as well as the criteria fordischarge home after treatment.

3. Discuss the clinical evidencesupporting the use of systemic ornebulized steroids in the treatmentof viral laryngotracheobronchitis.

Eric L. Wald, MD, is with the Division

of Critical Care Medicine, Northwestern

University, Chicago.

Address correspondence to: Eric L. Wald,

MD, 2300 Children’s Plaza, Box 73, Chicago,

IL 60614; fax: 773-880-6300; e-mail EWald@

childrensmemorial.org.

Dr. Wald has disclosed no relevant finan-

cial relationships.

doi: 10.3928/00904481-20091210-04

EDUCATIONAL OBJECTIVESCM E

Eric L. Wald, MD

© i S

t o c k p h

o t o . c

o m

CM E

3901EWald croup indd 153901EWald.croup.indd 15 1/6/2010 2:38:09 PM1/6/2010 2:38:09 PM



16 | www.PediatricSuperSite.com PEDIATRIC ANNALS 39:1 | JANUARY 2010

Because airway resistance is inversely

proportional to the fourth power of the

radius, minimal reductions in cross-sec-

tional area of the airway secondary to in-

flammation or edema can exponentially

increase airway resistance, as well as

work of breathing.

The term “croup” describes a constel-

lation of mainly acute and infectious ill-

nesses characterized by varying degrees

of barking cough, hoarseness, inspira-

tory stridor, and respiratory distress.

Most clinicians use the term “laryngo-

tracheitis” or “laryngotracheobronchi-

tis” for the most common form of croup

in which involvement of the larynx is

enough to produce typical symptoms,

and they reserve the term “laryngotra-

cheobronchopneumonitis” for more se-

vere disease that extends into the lower

airways. A distinction is made between

spasmodic croup, an entity thought to

have an allergic component that rarely

requires treatment, and laryngotrache-

itis, which is thought always to have an

infectious etiology. All these terms de-

scribe inflammation of the vocal cords

and structures inferior to the cords. In-

flammation of structures superior to the

cords, such as the epiglottis, arytenoids,

and aryepiglottic folds, is termed “su-

praglottitis.” All of these processes are

similar enough to consider them withinthe spectrum of a single disease. The

discussion here focuses on the history,

epidemiology, pathogenesis, clinical

presentation, and management of croup

illnesses: epiglottitis, laryngotracheitis

[including laryngotracheobronchitis

(LTB) and laryngotracheobronchopneu-

monitis], and bacterial tracheitis. Clas-

sification and clinical characteristics are

shown in Table 1 (see page 17).

EPIDEMIOLOGY

Croup occurs in children younger

than 6 years, with a peak incidence from7 to 36 months.2 Approximately 5% of

children have croup during the second

year of life. The incidence in boys is 1.4

to 2 times higher than in girls.2 Longi-

tudinal croup studies have described

a biennial mid-autumn peak in North

America, occurring in odd years, which

correlates with the prevalence of para-

influenza virus infection, as well as an

annual summer trough.3,4 The most fre-

quent etiologic agents include parain-

fluenza viruses (types 1-3), respiratory

syncytial virus, influenza viruses A and

B, and adenovirus, while Mycoplasma

pneumoniae, herpes simplex type I,

measles, and varicella have also been

reported. Human metapneumovirus and

human coronavirus HL-63 are two new-

ly described pathogens that are strongly

associated with croup in children.5

CLINICAL PRESENTATION

Patients with laryngotracheitis com-

monly present with 1 to 3 days of nonspe-

cific upper respiratory tract symptoms,

with progression to the characteristic

barking cough, stridor, and respiratory

distress. Symptom onset is abrupt and

typically occurs during nighttime hours.

Several hypotheses exist to explain the

nighttime onset, including nocturnal

airway cooling, gastroesophageal re-

flux and concomitant inflammation, and

the effect of nadir levels of cycling en-

dogenous substances, such as cortisol

and epinephrine.6,7

Inspiratory stridoris most common, with biphasic stridor

suggesting a more severe or fixed ob-

struction. Low-grade fever is often pres-

ent. Tachypnea, retractions, hypoxia, or

desaturation are often ominous signs of

worsening obstruction and impending

respiratory failure.

DIFFERENTIAL DIAGNOSIS

Children with classic croup symp-

toms are readily diagnosed, but clini-

cians must be cognizant that there may

be progression of infection into the tra-

chea and lower airways. Furthermore,there are several other acute obstructive

disease processes that occur in the lar-

ynx and are also present with stridor and

respiratory distress (see Sidebar). First

described in 1878 by Michel as angina

epiglottidea anterior, epiglottitis in chil-

dren has become a rarity since the intro-

duction of Hemophilus influenzae type

b (Hib) conjugate vaccines in 1991.8 It

represents a bacterial infection of the su-

praglottic structures in which worsening

edema forces the epiglottis posteriorly,

causing airway obstruction. Epiglottitis

usually occurs in patients 2 to 8 years,

although the average age is increas-

ing as is the ratio of adult to pediatric

cases since the introduction of the Hib

vaccine.9 Despite a sharp drop in inci-

dence, H. influenzae is still seen second-

ary to vaccine failure and in unimmu-

nized children. Group A beta hemolytic

Streptococcus is now the leading cause

of epiglottitis, although its absolute

frequency has not increased. Staphy-

lococci, pneumococci, moraxella, and

candida species, as well as many other

bacteria and viruses, have been isolated

from surface cultures of the epiglottis.

Children usually have rapid onset of

symptoms and present with throat pain,

a muffled, “hot potato” voice, fever, irri-

SIDEBAR.

Differential Diagnosisof Acute Laryngeal

Obstruction

• Acute laryngotracheitis

• Spasmodic croup

• Epiglottitis

• Bacterial tracheitis

• Foreign body aspiration(tracheal and esophageal)

• Laryngeal inflammation caused

by thermal injury

• Angioneurotic edema

• Allergic reaction

• Retropharyngeal abscess

• Peritonsillar abscess

• Neoplasm/hemangioma

• Vocal cord paresis/paralysis

• Laryngeal diphtheria

CM E





TABLE 1.

Classification, Definition, and Clinical Features of Croup Illnesses

Definition and

CharacteristicSpasmodic Croup Epiglottitis Acute Laryngotracheitis Bacterial Tracheitis

Definition

Acute nighttime onset

of inspiratory stridor;

sometimes associated

with mild URI or allergic

component

Inflammation of the

supraglottic struc-

tures, bacterial cel-

lulitis of the epiglottis,

and aryepiglottic folds

Inflammation of the larynx

and trachea

Inflammation of the larynx,

trachea and bronchi, or lung;

represents extension of laryn-

gotracheitis but more severe

illness pattern

Typical age at

occurrence3 months to 3 years 2 to 8 years 3 months to 3 years 3 months to 3 years

Individual and family

history

Possible family history of

croup; allergic historyNo family history

Possible family history of

croupPossible family history of croup

Prodrome Minimal coryza Minimal coryza Usually coryza Usually coryza

Onset

Sudden, always at night;

typically a well child or

with mild URI symptoms

who awakens with bark-

ing cough and/or stridor

Rapid progression

within hours

Variable, similar to common

cold presentation; fever in

first 24 hours and within 24

to 48 hours, stridor, or signs of

obstructed airway

Gradually progressive over 2 to

5 days; originally may present

like laryngotracheitis but refrac-

tory to typical therapy

Symptoms on

presentation

Hoarseness, barking

cough, minimal to mod-

erate inspiratory stridor,

no dysphagia, nontoxic

Fever, dysphagia,

odynophagia, drool-

ing, irritability; stridor

is a late finding, toxic

appearance

Hoarseness, barking cough,

minimal to severe inspiratory

stridor; no dysphagia, usually

nontoxic

Hoarseness, barking cough, usu-

ally severe inspiratory stridor;

typically toxic presentation

Signs on

presentation

No fever; no pharyngitis;

normal epiglottis

Fever, generally 37.8°

to 40.5° C; pharyngitis;

abnormal epiglottis

Fever, generally 37.8° to

40.5° C; minimal pharyngitis;

normal epiglottis

Fever, generally 37.8° to 40.5°

C; minimal pharyngitis; normal

epiglottis

Radiographic

findings

Subglottic narrowing on

posterior-anterior view

Thickening, round-

ing of epiglottis

(thumbprint sign); loss

of vallecular air space;

normal subglottis

Subglottic narrowing on

posterior-anterior view

Subglottic narrowing on poste-

rior-anterior view; irregular soft

tissue densities on lateral view,

bilateral pneumonia

White cell count NormalElevated with > 70%

neutrophils

Mildly elevated, with > 70%

neutrophils

Elevated or abnormally low, with

> 70% neutrophils/bandemia

Microbiologic

findings

Etiologic agents similarto those in laryngotra-cheitis

Haemophilus influenzae type B (with vaccinefailure and unim-munized), group Abeta-hemolytic Strep-

tococcus, Staphylococci,Pneumococci, Candida

Parainfluenza viruses (type 1responsible for fall outbreaks,type 3 for severe disease),influenza viruses, respiratorysyncytial virus, adenoviruses,

measles virus, rhinoviruses,metapneumoviruses, andcoronaviruses

Initial infection likely causedby viruses (parainfluenza orinfluenza), but evolution usuallydue to bacterial superinfection,particularly from Staphylococ-

cus aureus, group A Streptococci, and Haemophilus influenzae

LTB = laryngotracheobronchitis; LTBP = laryngotracheobronchopneumonia; adapted from Cherry JD34

CM E





tability and respiratory distress. Drool-

ing is common secondary to airway ob-

struction and odynophagia. Patients are

usually toxic appearing, often assum-

ing a sniffing position with the chin

thrust forward to open their airway, ora tripod position, leaning forward on

both arms to allow maximal use of ac-

cessory respiratory muscles. Notably, a

croupy cough is absent, and stridor is

a late clinical finding. Secondary sites

of infection, such as meningitis, otitis

media, and cellulitis, are present 50%

of the time, and pneumonia is reported

in up to 25% of cases.1,10

If the diagnosis is uncertain after

performance of the history and physi-

cal examination, a lateral radiograph

of the neck can aid in confirmation. In

epiglottitis, the lateral neck radiograph

often reveals a swollen and edematous

epiglottis (thumbprint sign), with loss

of the vallecular air space.

Once epiglottitis is suspected, a mul-

tidisciplinary team should be assembled,

including pediatric intensive care physi-

cians, anesthesiologists, and otolaryn-

gologists. To confirm the diagnosis, the

child should proceed to the operating

room for anesthesia, to obtain intrave-

nous access, and to perform laryngosco-

py with direct visualization and airway

placement. It is recommended that per-

sonnel be available to perform an emer-

gency tracheostomy if an airway cannot

be secured with an endotracheal tube.

Once the airway is secure, some prefer

changing the oral endotracheal tube to a

nasotracheal tube for easier positioning,

to minimize secretions and to prevent un-

necessary trauma. Cultures of the blood

and surface of the epiglottis should be

obtained for precise microbiologic diag-nosis. Antibiotics active against H. influ-

enzae type b and group A Streptococcus

should be started; children usually re-

quire intubation for 24 to 72 hours, until

reduction in airway edema occurs.

Another potentially life-threaten-

ing infection that often represents the

evolution of common croup to a more

acute disease is bacterial tracheitis. First

described in the American literature in

1912, it was re-described in 1979.11,12

Jones et al reported eight cases of a dis-

ease that shared features of croup and

epiglottitis. They called it “bacterial

tracheitis.”12 It occurs predominantly in

the fall and winter months in children 6

months to 6 years but has been reported

in older children. The most common

etiologic agent isolated is S. aureus, but

other pathogens, such as H. influenzae,

alpha-hemolytic Streptococcus, group A

Streptococcus, moraxella species, and

pneumococci, have also been reported.

Most view the disease as a complication

of viral laryngotracheitis in which injury

to respiratory epithelium predisposes to

bacterial superinfection.

The clinical presentation of bacterial

tracheitis is not as rapid as epiglottitis;

children usually have a mild to moder-

ate illness (typical of classic viral croup)

for several days before an acute change

or decompensation is noted. High fever,

productive cough, and a toxic appear-

ance is common, without odynophagia

or drooling. These last two features

are useful in differentiating bacterialtracheitis from epiglottitis. These pa-

tients often have an increased oxygen

requirement but respond poorly to

therapies, such as racemic epinephrine

and steroids that are aimed at reducing

airway edema. About 60% to 80% of

these children will require endotracheal

intubation and respiratory support due

to thick tracheal secretions that are the

cause of the obstruction.13,14 At the time

of endoscopy for intubation, subglottic

edema, thick inflammatory exudates,

mucosal ulceration, and sloughed mu-

cosa are observed. A bacterial culture

of tracheal secretions and a viral cul-

ture of the pharynx should be obtained

at the time of intubation to help guide

therapy. Concurrent sites of infection

are seen often with up to 60% of pa-

tients also having pneumonia.1 Lateral

neck x-rays can aid in diagnosis, reveal-

ing a hazy tracheal air column and soft

densities representing purulent material

or pseudomembranes. Treatment con-

sists of close airway monitoring and in-

travenous antibiotics active against the

common pathogens for 10 to 14 days.

A recent study found that bacterial tra-

cheitis was three times more likely to

cause respiratory failure than croup and

epiglottitis combined.14

TABLE 2.

Assessment of the Severity of Croup*

Level of Severity Characteristics

Mild Occasional barking cough, no audible stridor at rest, no chest wall retractions

Moderate Frequent barking cough, audible st ridor at rest, mi ld che st wa ll retra ctions at rest but no agitat ion

Severe Frequent barking cough, prominent stridor, tachypnea, and marked chest wall retractions; agitation and/or distress

Impending respiratory failureFrequent barking cough, stridor at rest, chest wall retractions (cough, stridor, retractions may not be prominent

due to increasing fatigue/airway compromise), lethargy or decreased level of consciousness, cyanosis

*Adapted from the Alberta Medical Association16

CM E





Other rare causes of stridor in chil-

dren presenting with croup-like symp-

toms include foreign body aspiration,

peritonsillar or retropharyngeal abscess,

angioneurotic edema, and laryngealdiphtheria. In foreign body aspiration,

there is usually a history of aspiration,

and symptoms are acute in onset, with-

out signs of prodrome or local or sys-

temic infection. Deep neck space infec-

tions tend to be preceded by viral upper

respiratory tract infections and a high

index of clinical suspicion is necessary

to diagnose them. Clinical findings, such

as fever, neck pain and swelling, and tor-

ticollis, are common, whereas signs of

airway obstruction, such as wheezing

and stridor, are relatively rare initially.

Drooling, limitation in neck movement,and cervical lymphadenopathy are other

presenting signs that may prompt medi-

cal attention. Angioedema or allergic

reactions are often associated with an

offending allergen, have an acute on-

set, and may be accompanied by other

findings, such as swollen lips and facial

tissue or urticarial rash. Finally, in the

unimmunized pediatric population, la-

ryngeal diphtheria must always be con-

sidered. Although there have been no

cases in the United States since 2003,

diphtheria still occurs in Asia, Africa,

and the former Soviet Union. It presents

with all of the hallmarks of laryngotra-

cheitis, but a membranous pharyngitis is

notable on physical examination.

ASSESSMENT OF SEVERITY

The diagnosis of croup usually re-

lies solely on astute clinical assessment.

The best known croup severity score,

the Westley score, evaluates five com-

ponents in the child with respiratory

distress: air entry, stridor, cyanosis, re-

tractions, and level of consciousness.15

In recent years, a more clinically use-

ful severity scale and clinical practice

guidelines were developed by the Alber-

ta Clinical Practice Guideline Working

Group.16 Based on this scale, less than

1% of children seen in 21 emergency

departments in Alberta, Canada, had se-

vere croup, while 85% of children had

mild croup17 (see Table 2, page 18).

TREATMENT

Despite the large body of anecdotal

testimonials supporting humidified air for

croup syndromes, there is no evidence-

based medicine to support its use. Sev-

eral randomized, controlled trials showed

no difference among groups in terms

of croup score, need for epinephrine or

steroid treatment, or need for additional

medical care or hospital admission.18,19

Corticosteroid Therapy

Until recently, a controversial is-

sue surrounding the treatment of croup

— corticosteroid therapy — is now uni-

formly recommended for croup of all lev-

els of severity. Meta-analyses of 37 trials

revealed lower croup scores at 6 hours

postmedication, a decrease in return vis-

its (in some cases up to 50% reduction)

and a decrease in time spent during the

emergency room visit or hospitalization.20

These benefits occurred in children with

mild to moderate croup and moderate to

severe croup. There was a fivefold de-

crease in the rate of intubation in children

with severe croup (or impending respira-

tory failure) among those who receivedsteroids.21 In children already intubated,

one-third less time was spent on the ven-

tilator, and there was a sevenfold decrease

in frequency of reintubation.22

Corticosteroid trials in croup have

investigated an assortment of drugs,

dosages, and routes of administration.

Single dose dexamethasone [0.6 mg/kg

given orally or intramuscularly (IM)]

has been studied and compared most

frequently. Oral dexamethasone, when

compared with other steroid prepara-

tions, such as oral prednisone, has been

found equivalent or superior in reducingcroup scores and in the rate of return to

medical care.23 Oral and IM administra-

tion of dexamethasone have been com-

pared, and no differences were seen in

reduction of croup scores, escalation of

medical care, return to medical care, or

hospital admission rates.24,25 Oral and

IM routes of administration have also

been compared with inhalational routes

(chiefly comparing inhaled budenoside

with oral dexamethasone) and they were

found to be equivalent. In some cases,

oral and IM routes were found to be su-

perior to inhalation.26,27 At the bedside,

the route of administration of steroid

may vary according to the tolerance of

the child and the associated symptoms

and severity of illness.

Dosing regimens for corticosteroids

have also been evaluated in various stud-

ies. Randomized trials showed the effi-

cacy of a single-dose administration and

multiple-dose administration of steroids

in croup. Because the duration of ac-

tion for a single dose of dexamethasone

is 48 to 96 hours, it seems sufficient to

treat the most common croup symptoms

in children. No studies have performed

outcome analyses comparing single

dose therapy with multiple dose treat-

ment schedules. Randomized, controlled

Corticosteroid trials in

croup have investigated an

assortment of drugs, dosages,

and routes of administration.

CM E





studies have shown that 0.15 mg/kg of

dexamethasone may be adequate in chil-

dren with croup, although the severity of

illness in those studies was variable.28,29

In contrast, a meta-analysis of severalstudies reported that a higher initial dose

of steroids was associated with clinical

improvement in a larger proportion of

hospitalized croup patients.21

Steroid treatment for croup is gener-

ally thought to be safe, especially when

limited to a single dose. The American

Academy of Pediatrics (AAP) and the

U.S. Food and Drug Administration

(FDA) recommend caution when using

steroids in children exposed to the vari-

cella virus, although there is controversy

about whether inhaled steroids or a sin-

gle systemic dose can be harmful.

Epinephrine

Nebulized epinephrine has been well

studied and is usually reserved for chil-

dren with moderate to severe croup, serv-

ing as a temporary treatment bridge to

allow the steroids to take effect. It likely

works by stimulating the alpha-adrener-

gic receptors in airway mucosa, resulting

in vasoconstriction of precapillary arteri-

oles. This decreases hydrostatic pressure,

allows fluid absorption, and decreases air-

way edema. Racemic epinephrine, a 1:1

mixture of the levo and dextro isomers of

epinephrine, has been used in the United

States since 1971. Early trials of 2.25%

racemic epinephrine (0.5 mL in 2.5 mL

normal saline) administered via intermit-

tent positive pressure breathing showed

reduction of croup severity scores.15,30

Later trials revealed that nebulized ad-

ministration of racemic epinephrine was

an equally effective route for treating air-

way obstruction, improving croup scores

within 10 to 30 minutes.31 Nebulization

of L-epinephrine (1:1000) diluted in 5

mL of saline provides similar efficacy in

children with moderate to severe croup,

although the racemic form is most com-

monly used in the United States.32 Clini-

cal effects last up to 1 to 2 hours, and with

the development of rebound tracheal ede-

ma, patients may return to their baseline

level of distress but rarely worsen.15,33

Repeated doses are often necessary and

have been reported to reduce the needfor intubation in children with severe

croup.34 Prospective studies suggest that

patients receiving epinephrine and ste-

roids may be discharged home safely

from the emergency department after an

observation period of 2 to 4 hours, as long

as their symptoms have not recurred.35,36

If treatment fails to abolish croup symp-

toms, or multiple epinephrine doses have

been used, admission for clinical obser-

vation is warranted.

Although nebulized epinephrine is

generally safe, one case report describes

ventricular tachycardia and myocardial

infarction in a previously healthy child

with severe croup who received three

nebulized treatments within 1 hour.37

Helium

Helium-oxygen mixtures (heliox)

have been demonstrated to be an effective

treatment for upper airway obstruction,

including croup syndromes. Because

the density of helium is one-seventh that

of air, heliox decreases turbulence and

improves gas flow through high-resis-tance airways. A 70:30 helium:oxygen

mixture of heliox was compared with

racemic epinephrine in a small prospec-

tive, randomized, double-blind trial in

hospitalized children with moderate to

severe croup who were already receiv-

ing steroids.38 There was no difference

in the modified croup score between the

two treatment groups. A significant oxy-

gen requirement (greater than 40%) lim-

its the use of heliox, as does its expense

and complexity of setup. It also serves

more as a therapeutic bridge because it

lacks a direct effect on inflamed, edema-tous airways. Heliox can reduce work of

breathing enough to prevent intubation

and allow other medications to reach

therapeutic peak. Heliox has a lower

side effect profile than corticosteroids

and epinephrine, however, and may be

useful in those children in whom those

medications are contraindicated.

Other Treatments

Children experiencing hypoxia with

moderate to severe croup should receive

oxygen therapy. Antitussive and decon-

gestant agents have no role in the treat-

ment of croup illnesses. Antibiotics are

unnecessary in the treatment of laryn-

gotracheitis and spasmodic croup unless

clinical symptoms, laboratory data, or

microbiology support the presence of

secondary bacterial infection. Antiviral

therapy can be considered in cases of in-

fluenza virus infection.

CONCLUSIONS AND FUTURE

CONSIDERATIONS

Croup in its most common form

(laryngotracheitis) is a pediatric respi-

ratory illness that provokes anxiety in

the patient and their parents because of

airway obstruction. Despite anecdotal

evidence, cool mist or humidified air

Heliox can reduce work of

breathing enough to prevent

intubation and allow for

other medications to reach

therapeutic peak.

CM E





has not been proven to be effective in

the treatment of croup. Regardless of

the level of illness acuity, corticoste-

roid therapy (0.6 mg/kg dexamethasone

either orally or IM) is now the standardof care. In cases of milder disease, re-

assurance and close outpatient obser-

vation is recommended. Patients with

moderate symptoms or those who fail

to respond to corticosteroids should be

evaluated in an emergency department.

There is evidence to support the use

of epinephrine for short-term relief of

symptoms, and it may be a useful thera-

peutic bridge until the effect of steroids

is realized. In children who appear toxic

or in severe respiratory distress, endos-

copy, blood work, as well as bacterial

and viral cultures, may be useful. Re-peated epinephrine doses and inhaled

helium-oxygen mixture may help avoid

intubation in severe cases. Admission

to the ICU, intravenous antibiotics, and

intubation may be required to support

these children through severe illness.

REFERENCES 1. Jardine DS, Martin LD. Specific Diseases of

the Respiratory System: Upper Airway. In:

Fuhrman BP, Zimmerman J. Pediatric Criti-

cal Care. 3rd ed. Philadelphia, PA: Mosby

Elsevier; 2006:571-587.

2. Denny FW, Murphy TF, Clyde WA, Col-

lier AM, Henderson FW. Croup: an 11-year

study in a pediatric practice. Pediatrics.

1983;71(6):871-876.

3. Segal AO, Crighton EJ, Moineddin R, Mam-

dani M, Upshur RE. Croup hospitalizations in

Ontario: a 14-year time-series analysis. Pedi-

atrics. 2005;116(1):51-55.

4. Marx A, Torok T, Holman R, Clarke M, An-

derson L. Pediatric hospitalizations for croup

(laryngotracheobronchitis): biennial increases

associated with human parainfluenza virus 1 epi-

demics. J Infect Dis. 1997;176(6):1423-1427.

5. van der Hoek L, Sure K, Ihorst G, et al. Human

coronavirus NL63 infection is associated with

croup. Adv Exp Med Biol. 2006;581:485-491.

6. Calhoun W. Nocturnal asthma. Chest.

2003;123(3 Suppl):399-405.

7. Bjornson CL, Johnson DW. Croup. Lancet.

2008;371(9609):329-339.

8. Theisen CF. Angina epiglottidea anterior:

report of three cases. Albany Med Ann.

1900;21:395-405.

9. Shah RK, Roberson DW, Jones DT. Epiglot-

titis in the hemophilus influenza type B vac-

cine era: changing trends. Laryngoscope.

2004;114(3):557-560.

10. Stroud RH, Friedman NR. An update on in-

flammatory disorders of the pediatric airway:

epiglottitis, croup, and tracheitis. Amer J Oto-

laryng. 2001;22(4):268-275.

11. Jackson C. Influenzal tracheitis. Laryngo-

scope. 1912;22:130.

12. Jones R, Santos JI, Overall JC. Bacterial tra-

cheitis. JAMA. 1979;242(8):721-726.

13. Bernstein T, Brilli R, Jacobs B. Is bacterial

tracheitis changing? A 14-month experience

in a pediatric intensive care unit. Clin Infect

Dis. 1998;27(3):458-462.

14. Hopkins A, Lahiri T, Salerno R, Heath B.

Changing epidemiology of life-threaten-

ing upper airway infections: the reemer-

gence of bacterial tracheitis. Pediatrics.

2006;118(4):1418-1421.

15. Westley CR, Cotton EK, Brooks JG. Nebu-

lized racemic epinephrine by IPPB for the

treatment of croup: a double-blind study. Am

J Dis Child. 1978;132(5):484-487.

16. Guideline for the diagnosis and management

of croup. Alberta, ON, Canada: Alberta Medi-

cal Association; 2007.

17. Bjornson CL, Johnson DW. Croup —

treatment update. Pediatr Emerg Care.

2005;21(12):863-873.

18. Moore M, Little P. Humidified air inhalation

for treating croup. Cochrane Database Syst

Rev, 2006;3:CD002870.

19. Scolnik D, Coates AL, Stephens D, Da Silva

Z, Lavine E, Schuh S. Controlled delivery of

high vs low humidity vs mist therapy for croup

in emergency departments: a randomized con-

trolled trial. JAMA. 2006;295(11):1274-1280.

20. Russell K, Wiebe N, Saenz A, et al. Gluco-

corticoids for croup. Cochrane Database Syst

Rev. 2004;1:CD001955.

21. Kairys SW, Olmstead EN, O’Connor GT. Ste-

roid treatment of laryngotracheitis: a meta-

analysis of the evidence from randomized

trials. Pediatrics. 1989;83(5):683-693.

22. Tibballs J, Shann FA, Landau LI. Placebo-con-

trolled trial of prednisolone in children intubated

for croup. Lancet. 1992;340(8822):745-748.

23. Sparrow A, Geelhoed G. Prednisolone versus

dexamethasone in croup: a randomized equiva-

lence trial. Arch Dis Child. 2006;91(7):580-583.

24. Rittichier K, Ledwith C. Outpatient treatment

of moderate croup with dexamethasone: in-

tramuscular versus oral dosing. Pediatrics.

2000;106(6):1344-1348.

25. 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.

26. Geelhoed GC. Budesonide offers no advan-

tage when added to oral dexamethasone in

the treatment of croup. Pediatr Emerg Care.

2005;21(6):359-362.

27. Klassen T, Craig W, Moher D, et al. Nebu-

lized budesonide and oral dexamethasone for

treatment of croup: a randomized controlled

trial. JAMA. 1998;279(20):1629-1632.

28. Geelhoed GC, Macdonald W. Oral dexameth-

asone in the treatment of croup: 0.15 mg/kg

versus 0.3 mg/kg versus 0.6 mg/kg. Pediatr

Pulmonol. 1995;20(6):362-368.

29. Chub-Uppakarn S, Sangsupawanich P. A ran-

domized comparison of dexamethasone 0.15

mg/kg versus 0.6 mg/kg for the treatment of

moderate to severe croup. Internat J Pediatr

Otorhinolaryngol. 2007;71(3):473-477.

30. Taussig LM, Castro O, Beaudry PH, Fox WW,

Bureau M. Treatment of laryngotracheobron-

chitis (croup): use of intermittent positive-

pressure breathing and racemic epinephrine.

Am J Dis Child. 1975;129(7):790-793.

31. Fogel JM, Berg IJ, Gerber MA, Sherter CB.

Racemic epinephrine in the treatment of

croup: nebulization alone versus nebulization

with intermittent positive pressure breathing.

J Pediatr. 1982;101(6):1028-1031.

32. Waisman Y, Klein BL, Boenning DA, et al. Pro-

spective randomized double-blind study com-

paring L-epinephrine and racemic epinephrine

aerosols in the treatment of laryngotracheitis

(croup). Pediatrics. 1992;89(2):302-306.

33. Kristjansson S, Berg-Kelly K, Winso E. Inha-

lation of racemic adrenaline in the treatment

of mild and moderately severe croup: clinical

symptom score and oxygen saturation mea-

surements for evaluation of treatment effects.

Acta Paediatrica. 1994;83(11):1156-1160.

34. Cherry JD. Croup. New Eng J Med.

2008;358(4):384-391.

35. Johnson DW, Jacobson S, Edney P, et al. A

comparison of nebulized budesonide, in-

tramuscular dexamethasone, and placebo

for moderately severe croup. N Engl J Med.

1998;339(8):498-503.

36. Rizos J, DiGravio B, Sehl B, et al. The dis-

position of children with croup treated with

racemic epinephrine and dexamethasone

in the emergency department. J Emer Med.

1998;16(4):535-539.

37. Butte M, Nguyen B, Hutchison T, et al.

Pediatric myocardial infarction after race-

mic epinephrine administration. Pediatrics.

1999;104(1):e9.

38. Weber JE, Chudnofsky CR, Younger JG, et al.

A randomized comparison of helium-oxygen

mixture (Heliox) and racemic epinephrine for

the treatment of moderate to severe croup. Pe-

diatrics. 2001;107(6):E96.

CM E




Reproducedwithpermissionof thecopyrightowner. Further reproductionprohibitedwithoutpermission.

croup. sindrome

Documents