AUTHOR INFORMATION

Section 1 of 11

Authored by Mark Louden, MD, FACEP, Consulting Staff, Emergency Department, Duke Health Raleigh Hospital

Mark Louden, MD, FACEP, is a member of the following medical societies: American Academy of Emergency Medicine, and American College of Emergency Physicians

Edited by Kirsten Bechtel, MD, Assistant Professor, Department of Pediatrics, Division of Pediatric Emergency Medicine, Yale-New Haven Children's Hospital; Robert Konop, PharmD, Director, Clinical Account Management, Ancillary Care Management, Inc; Wayne Wolfram, MD, MPH, Clinical Associate Professor, Departments of Pediatrics, Children's Hospital and University of Cincinnati; John Halamka, MD, Chief Information Officer, CareGroup Healthcare System, Assistant Professor of Medicine, Department of Emergency Medicine, Beth Israel Deaconess Medical Center; Assistant Professor of Medicine, Harvard Medical School; and Richard G Bachur, MD, Assistant Professor of Pediatrics, Harvard Medical School; Associate Chief and Fellowship Director, Division of Emergency Medicine, Children's Hospital of Boston

Author's Email:	Mark Louden, MD, FACEP
Editor's Email:	Kirsten Bechtel, MD

eMedicine Journal, February 6 2006, VOLUME 7, Number 2

INTRODUCTION

Section 2 of 11

Background: Bronchiolitis is an acute infectious disease of the lower respiratory tract that occurs primarily in young infants, most often in those aged 2-24 months.

Pathophysiology: Bronchiolitis is usually due to a viral infection of the small airways (bronchioles). Infection of bronchiolar respiratory and ciliated epithelial cells produces increased mucus secretion, cell death, and sloughing, followed by a peribronchiolar lymphocytic infiltrate and submucosal edema. The combination of debris and edema produces critical narrowing and obstruction of small airways.

Decreased ventilation of portions of the lung causes ventilation/perfusion mismatching, resulting in hypoxia. During the expiratory phase of respiration, further dynamic narrowing of the airways produces disproportionate airflow decrease and resultant air trapping. Work of breathing is increased due to increased end-expiratory lung volume and decreased lung compliance. Recovery of pulmonary epithelial cells occurs after 3-4 days, but cilia do not regenerate for about 2 weeks. The debris is cleared by macrophages.

Infection is spread by direct contact with respiratory secretions. In the United States, epidemics last 2-4 months beginning in November and peaking in January or February. While 93% of cases occur between November and early April, sporadic cases may occur throughout the year. Attack rates within families are as high as 45% and are higher in daycare centers. Rates of hospital-acquired infection range from 20-47%. Previous infection with the common etiologic viruses does not confer immunity. Reinfection is common.

Frequency:

• In the US: Annual incidence is 11.4% in children younger than 1 year and 6% in those aged 1-2 years. The illness accounts for 4500 deaths and 90,000 hospital admissions per year. Prevalence may be higher in urban areas.

  In children aged 2 years, approximately 95% have serologic evidence of past infection with the predominant causative agent, respiratory syncytial virus (RSV). Unfortunately, presence of antibodies to RSV does not confer immunity.

• Internationally: RSV is an important respiratory pathogen worldwide. The frequency of bronchiolitis in developed countries appears to be similar to that in the United States. Epidemiologic data for underdeveloped countries are incomplete. Peak incidence of bronchiolitis usually occurs during winter months in temperate climates and during the rainy season in tropical climates. In the United States, the peak occurs in February. Morbidity and mortality may be higher in less developed countries because of poor nutrition and lack of resources for supportive medical care.

Mortality/Morbidity: Significant morbidity is unusual.

• Hospitalization is required in up to 2% of cases; most of those patients are younger than 6 months. These patients account for as many as 17% of all infant hospitalizations. Mechanical ventilation is required for 3-7% of admitted patients.

• Mortality rate is 1-2% of all hospitalized patients and 3-4% for patients with underlying cardiac or pulmonary disease.

• Most deaths occur in infants younger than 6 months.

Race:

• Race and socioeconomic status may affect the frequency of contracting bronchiolitis.

• Lower socioeconomic status may increase the likelihood of hospitalization. Hospitalization rates are higher in Native American populations, but it is not clear if this is due to more severe infection or a lower threshold for admission.

• Some clinical studies suggest that morbidity may be higher in minority races.

Sex: Bronchiolitis occurs as many as 1.25 times more frequently in males than in females.

Age:

• Although infection with etiologic agents may occur at any age, the clinical entity of bronchiolitis includes only infants and young children. Seventy-five percent of cases of bronchiolitis occur in children younger than 1 year, and 95% in children younger than 2 years. Incidence peaks in those aged 2-8 months.

CLINICAL

Section 3 of 11

History:

• Early symptoms are those of a viral upper respiratory tract infection (URI), including mild rhinorrhea, cough, and sometimes low-grade fever.

• Adults, older children, and many infants do not progress beyond this stage of URI.

• For the 40% of infants and young children who progress to lower respiratory tract involvement, paroxysmal cough and dyspnea develop within 1-2 days.

• Other common symptoms include the following:

• Fever

• Increased work of breathing

• Wheezing

• Cyanosis

• Grunting

• Noisy breathing

• Vomiting, especially post-tussive

• Irritability

• Poor feeding or anorexia

Physical: Most patients with bronchiolitis have the following signs:

• Tachypnea, often at rates over 50-60 breaths per minute (most common physical sign)

• Tachycardia

• Fever, usually in the range of 38.5-39°C

• Mild conjunctivitis or pharyngitis

• Diffuse expiratory wheezing

• Nasal flaring

• Intercostal retractions

• Cyanosis

• Inspiratory crackles

• Otitis media

• Apnea, especially in infants younger than 6 weeks

• Palpable liver and spleen from hyperinflation of the lungs and consequent depression of the diaphragm

Causes: RSV is the most common pathogen (85%), but other organisms occasionally produce a similar clinical picture.

• Adenovirus (11%) occasionally causes a similar syndrome with a more virulent course.

• Epidemics of bronchiolitis due to parainfluenza virus usually begin earlier in the year and tend to occur every other year.

• Other less common etiologic agents include the following:

• Mycoplasma pneumoniae

• Enterovirus

• Influenza virus

• Rhinovirus

• Chlamydia pneumoniae

• Ear, nose, or mouth inoculation

• Exposure to an adult with a URI

• Daycare exposure (significant)

• Idiopathic

DIFFERENTIALS

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Asthma
Bronchitis
Congestive Heart Failure and Pulmonary Edema
Pediatrics, Apnea
Pediatrics, Foreign Body Ingestion
Pediatrics, Pneumonia
Pneumonia, Aspiration
Pneumonia, Bacterial
Pneumonia, Mycoplasma
Pneumonia, Viral

Other Problems to be Considered:

Cystic fibrosis
Vascular ring
Lobar emphysema
Foreign body
Cardiac disease
Reflux
Aspiration

WORKUP

Section 5 of 11

Lab Studies:

• A complete blood count (CBC) is seldom useful since the white blood cell (WBC) count is usually within normal limits.

• Urine specific gravity may provide useful information regarding fluid balance and possible dehydration.

• Serum chemistries are not affected directly by the infection but may aid in gauging severity of dehydration.

• Arterial blood gases (ABG) may be needed in the severely ill patients, especially those requiring mechanical ventilation.

Imaging Studies:

• Chest radiographs should include anterior-posterior (AP) and lateral views.

• Hyperinflation and patchy infiltrates may be seen; these findings are nonspecific and may be observed in asthma, viral or atypical pneumonia, and aspiration.

• Focal atelectasis

• Air trapping

• Flattened diaphragm

• Increased anteroposterior diameter

• Peribronchial cuffing

• Chest radiographs may also reveal evidence of alternative diagnoses, such as lobar pneumonia, congestive heart failure, or foreign body aspiration.

Other Tests:

• Antigen tests of nasal washings provide rapid (usually within 30 min) and accurate (sensitivity 87-91%, specificity 96-100%) detection of RSV.

• A positive culture or direct fluorescent antibody test result can confirm the diagnosis of RSV infection.

• Nasal washings should be obtained from children requiring hospitalization and children at risk for severe disease.

• Cultures of RSV are considerably less sensitive (60%) but are 100% specific.

• Respiratory viral panels, cultures for RSV or other viruses, or detection by direct fluorescent antibody (DFA) or polymerase chain reaction (PCR) may be useful for the following reasons:
  • As another means of confirmation

  • To search for other possible infectious agents

  • For epidemiologic purposes

TREATMENT

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Prehospital Care: Prehospital care consists of cardiorespiratory monitoring, positioning to facilitate respiratory efforts (ie, upright posture), administration of oxygen, and a trial of bronchodilators.

Emergency Department Care:

• General supportive measures are the mainstay of treatment for patients with bronchiolitis.

• Patients should be made as comfortable as possible (held in a parent's arms or sitting in the position of comfort).

• Cardiorespiratory monitoring is essential.

• Pulse oximetry is a helpful tool, as hypoxia is common.

• Humidified oxygen should be administered if the oxygen saturation is less than 94% on room air.

• The ability to maintain adequate hydration should be assessed by observing patient oral intake. Many dyspneic infants have difficulty taking a bottle.

• Fever and tachypnea increase insensible fluid losses.

• Early effort should be made to isolate or cohort patients confirmed or likely to have RSV infection, especially from other patients at risk for severe disease.

• Antibiotics are not indicated unless bacterial infection is suggested (eg, toxic appearance, hyperpyrexia, consolidation or focal lobar infiltrates on chest radiograph, leukocytosis, positive bacterial cultures).

• Concomitant otitis media is common and may be treated with oral antibiotics.

Consultations: Early consultation with a pediatrician is advisable when the need for admission is anticipated. Intensive care consultation should be sought for patients who are severely ill.

MEDICATION

Section 7 of 11

Drug Category: Adrenergic agents -- The use of bronchodilators is controversial. These agents relieve reversible bronchospasm by relaxing smooth muscles of the bronchi. Meta-analyses of clinical studies show little or no benefit from treatment with inhaled beta-adrenergic agents (with or without ipratropium bromide). These are plagued by the heterogeneous methods of the studies included. Empiric treatment with beta-agonists seems to be the standard of care. Drugs and dosages are the same as those for asthma. Nebulized epinephrine may occasionally be useful.

Drug Name	Albuterol (Proventil, Ventolin, Salbutamol) -- Beta-agonist for bronchospasm refractory to epinephrine. Relaxes bronchial smooth muscle by action on beta2-receptors with little effect on cardiac muscle contractility. May inhibit airway microvascular leakage.
Adult Dose	Nebulizer: 5 mg/mL; 5 mg q15-20min for 3 doses, or continuous nebulization Inhalant: 90 mcg/puff; 4-8 puffs q20min up to 4 h, then 2-4 puffs q1-4h; use with a spacer device
Pediatric Dose	Nebulizer: (5 mg/mL) 0.15 mg/kg (2.5-5 mg) q15-20min for 3 doses, then 0.15-0.3 mg/kg q1-4h prn or 0.5 mg/kg/h continuous nebulization Inhalant: 90 mcg/puff; 4-8 puffs q20min up to 4 h, then q1-4h prn; use with a spacer device
Contraindications	Documented hypersensitivity
Interactions	Beta-adrenergic blockers antagonize effects; inhaled ipratropium may increase duration of bronchodilatation by albuterol; cardiovascular effects may increase with MAOIs, inhaled anesthetics, TCAs, and sympathomimetic agents
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Caution in hyperthyroidism, diabetes mellitus, and cardiovascular disorders; decreased serum potassium may occur

Drug Name	Epinephrine (Adrenaline) -- No proven advantage over inhaled beta2-agonists exists.
Adult Dose	0.3-0.5 mL of 1:1000 solution SC q20min up to 3 doses
Pediatric Dose	0.01 mL/kg of 1:1000 solution SC q15-20min, not to exceed 0.3 mL Nebulizer: <2 years: 0.25 mL of 2.25% solution in 3 mL NS >2 years: 0.5 mL of 2.25% solution in 3 mL NS
Contraindications	Documented hypersensitivity; cardiac arrhythmias or angle-closure glaucoma; local anesthesia in areas such as fingers or toes because vasoconstriction may produce sloughing of tissue; not to use during labor (may delay second stage of labor)
Interactions	Increases toxicity of beta-blocking and alpha-blocking agents and that of halogenated inhalational anesthetics
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Caution in elderly patients, prostatic hypertrophy, hypertension, cardiovascular disease, diabetes mellitus, hyperthyroidism, and cerebrovascular insufficiency; rapid IV infusions may cause death from cerebrovascular hemorrhage or cardiac arrhythmias

Drug Category: Anticholinergics -- Inhibits smooth muscle contraction. These agents are useful in patients with a significant bronchospasmodic component of illness.

Drug Name	Ipratropium (Atrovent) -- Chemically related to atropine. Quaternary ammonium anticholinergic bronchodilator acting at muscarinic receptors of parasympathetic nervous system. Has antisecretory properties and, when applied locally, inhibits secretions from serous and seromucous glands lining the nasal mucosa. It is synergistic with beta2-agonists.
Adult Dose	Nebulizer: 1 unit dose vial (500 mcg) mixed with albuterol solution q20min for 3 doses, then q2-4h prn MDI: 2 inhalations qid; not to exceed 12 inhalations/d
Pediatric Dose	Nebulizer: 250 mcg mixed with albuterol solution q20min for 3 doses, then q2-4h prn
Contraindications	Documented hypersensitivity
Interactions	Drugs with anticholinergic properties, such as dronabinol, may increase toxicity; albuterol may increase effects
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	Not indicated for acute episodes of bronchospasm; caution in narrow-angle glaucoma, prostatic hypertrophy, and bladder neck obstruction

Drug Category: Corticosteroids -- Clinical trials demonstrate that corticosteroids have no benefit in the treatment of bronchiolitis. However, one study (with a treatment group of 8 patients) showed some clinical improvement with the combination of dexamethasone and salbutamol. A larger and more recent double-blind, placebo-controlled trial of the same agents revealed no difference from placebo.
Nebulized steroid treatment has not been proven efficacious.
A subsequent study of prednisolone treatment of inpatients appeared to show a small benefit in a subgroup of 14 intubated patients. Corticosteroids may be useful in patients with history of reactive airway disease.
Steroid treatment has not been shown to decrease the long-term incidence of wheezing or asthma after RSV infection.

Drug Name	Prednisone (Deltasone) -- Blocks release of inflammatory mediators by inhibition of phospholipase A2. May be useful in patients with asthma or in bronchiolitis with asthmatic qualities.
Adult Dose	60 mg PO initial, then 40-60 mg qd for 5-10 d; taper for longer period
Pediatric Dose	2 mg/kg PO initial, then 1 mg/kg/d in 1-2 daily doses; not to exceed 60 mg/d for 3-10 d; taper for longer periods
Contraindications	Documented hypersensitivity; fungal, viral, connective tissue, or tubercular skin infections; peptic ulcer disease; hepatic dysfunction; GI disease
Interactions	Coadministration with estrogens may decrease prednisone 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	C - Safety for use during pregnancy has not been established.
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	Methylprednisolone (Medrol, Solu-Medrol) -- Blocks release of inflammatory mediators by inhibition of phospholipase A2. May be useful in patients with asthma or in bronchiolitis with asthmatic qualities.
Adult Dose	60-80 mg IV
Pediatric Dose	2 mg/kg PO initial, then 1 mg/kg/d qd/bid; not to exceed 60 mg/d for 3-10 d; taper for longer periods; 0.5-2 mg/kg IV q6h
Contraindications	Documented hypersensitivity; viral, fungal, or tubercular skin infections
Interactions	Coadministration with digoxin, may increase digitalis toxicity secondary to hypokalemia; estrogens may increase levels; phenobarbital, phenytoin, and rifampin may decrease levels of methylprednisolone (adjust dose); monitor patients for hypokalemia when taking medication concurrently with diuretics
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Hyperglycemia, edema, osteonecrosis, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, growth suppression, myopathy, and infections are possible complications of glucocorticoid use

Drug Category: Nucleoside analog -- Inhibits viral replication by inhibiting DNA and RNA synthesis.

Drug Name	Ribavirin (Virazole) -- May be used for inpatients who have, or who are at high risk for, severe RSV infection. In early trials, 3-7 d of ribavirin therapy produced significant reduction in mortality, length of hospitalization, and duration of mechanical ventilation. However, recent studies demonstrate no clinical benefit. Furthermore, this therapy is very expensive. Use of aerosolized ribavirin in mechanically ventilated patients requires administration by physicians and support staff familiar with this mode of administration and the specific ventilator.
Pediatric Dose	20 mg/mL initial solution, with continuos aerosol administration of 12-18 h/d for 3-7 d
Contraindications	Documented hypersensitivity
Interactions	Zidovudine effects are decreased when administered concurrently with ribavirin
Pregnancy	X - Contraindicated in pregnancy
Precautions	Monitor closely patients with COPD and asthma for deterioration of respiratory function; sudden deterioration of respiratory function associated with aerosolized ribavirin in infants

FOLLOW-UP

Section 8 of 11

Further Inpatient Care:

• Patients at high risk and patients with moderate respiratory distress or persistent hypoxemia should be admitted for the following:

• Supplemental oxygen

• Apnea monitoring if indicated by age or history (RSV is associated with central apnea for unknown reasons. Term infants younger than age 1 month and premature infants younger than 48 weeks postconception are at highest risk.)

• Restoration and/or maintenance of fluid balance

• Children with severe respiratory distress or impending respiratory failure should be admitted to a pediatric ICU.

• Otherwise healthy children with bronchiolitis have a low risk for bacterial superinfection or coexisting bacterial infection. The febrile infant with findings consistent with bronchiolitis but no other apparent source of infection may require some evaluation for alterative bacterial sources especially if very young ( <3 mo) or if he or she appears ill.

• Children with underlying cardiopulmonary disease, infants with a history of gestational age less than 34 weeks, infants younger than 6 weeks, and infants with congenital or acquired immunodeficiency are at high risk for severe RSV infection and require heightened vigilance. These patients should be referred to a facility where pediatric intensive care and pediatric subspecialty consultation are available.

• Suggested guidelines for admission are as follows:

• Oxygen saturation less than 94% after therapy

• Respiratory distress (eg, respiratory rate >60/min or retractions at rest)
  

• Apnea or risk of apnea

• Age younger than 2 months or history of prematurity

• Underlying cardiopulmonary disease or immunosuppression

Further Outpatient Care:

• Patients with mild disease with reliable caregivers may be discharged. Follow-up evaluation with a primary care provider within 24 hours is desirable.

• Criteria for discharge

• No respiratory distress (eg, respiratory rate <60/minute) at rest or with feeding

• Minimal retractions at rest (not crying)

• Adequate hydration

• SaO₂ > 93%

• Age older than 2 months without a history of prematurity

• Reliable caregivers with transportation available

• No underlying cardiopulmonary disease

• Able to take liquids by mouth without difficulty

In/Out Patient Meds:

• Beta-agonists, administered by inhaler or nebulizer, may be continued as an outpatient if the child responds to them while in the ED.

• If inhalers are prescribed, a mask and spacer should be provided and the patient's caregiver instructed in their use prior to discharge.

Transfer:

• Severely ill children should be admitted to a pediatric or neonatal intensive care unit. If this requires transfer to another hospital, transport personnel and vehicles specifically intended for pediatric transport are desirable.

Prognosis:

• Most children with bronchiolitis, regardless of severity, recover without sequelae. The course of disease is usually 7-10 days, but a few remain ill for weeks.

• Bronchiolitis has been identified as a risk factor for asthma, but this does not necessarily imply causation. Children already predisposed to asthma may be more likely to wheeze when they have RSV or other respiratory infectious or allergic stimuli. On the other hand, it is postulated that RSV infection may predispose an individual to later bronchospasm by selective promotion of specific subsets of helper T cells.

Patient Education:

• Instructions at discharge include positioning, maintenance of oral hydration, temperature control, use of prescribed medications, avoidance of exposure to tobacco smoke or other irritants, methods to limit transmission (eg, hand washing, avoiding day care while ill), and criteria for return to the ED.

MISCELLANEOUS

Section 9 of 11

Special Concerns:

• Children with underlying cardiopulmonary disease, including congenital heart disease, bronchopulmonary dysplasia, premature infants, infants younger than 6 weeks and infants with congenital or acquired immunodeficiency (including transplant recipients) are at high risk for severe RSV infection.

• In addition to heightened vigilance, these patients may require specialized and intensive care.

TEST QUESTIONS

Section 10 of 11

CME Question 1: A 6-month-old previously healthy infant presents with cough and dyspnea for one day and a temperature of 38.5°C. His 20-month-old sister was diagnosed several days ago with bronchiolitis. No family history of asthma exists. Except for fever, respiratory rate of 44/min, wheezing, and mild retractions, his examination is normal. A pulse oximeter reading is 92%. Which of the following treatments is indicated?

A: Oxygen, albuterol and prednisolone
B: Oxygen, albuterol and ribavirin
C: Oxygen, albuterol and IV fluids
D: Oxygen and albuterol
E: None of the above

The correct answer is D: Oxygen should be administered if the oxygen saturation is less than 94%. Alpha-adrenergic agents are not of proven benefit in bronchiolitis but may be beneficial for some infants. Corticosteroids have no demonstrated clinical benefit.

CME Question 2: Which of the following medications may be indicated for the treatment of a patient who has received aggressive bronchodilator treatment and demonstrates bronchiolitis, a history of bronchopulmonary dysplasia (BPD), a positive respiratory syncytial virus (RSV) culture, and a pulse oximetry reading of 78% on 40% oxygen?

A: Ribavirin
B: RSV immune globulin
C: Palivizumab
D: Erythromycin
E: Cefotaxime

The correct answer is A: Ribavirin may be useful in severely ill patients and patients with serious underlying conditions but is not normally initiated in the ED. Antibiotics are not useful without evidence of bacterial infection. Immune globulin or palivizumab may have a role in prevention of RSV infection in children at risk for severe infection but have no role in ED treatment.

Pearl Question 1 (T/F): Respiratory syncytial virus (RSV) and parainfluenza virus are the 2 most common etiologic agents of bronchiolitis. Adenovirus causes a virulent form.

The correct answer is True: RSV is the most common pathogen (85%), but other organisms occasionally produce a similar clinical picture. Adenovirus (11%) occasionally causes a similar syndrome with a more virulent course. Epidemics of bronchiolitis due to parainfluenza virus usually begin earlier in the year and tend to occur every other year.

Pearl Question 2 (T/F): Winter (or the rainy season in tropical countries) is the season when epidemics of respiratory syncytial virus (RSV) occur.

The correct answer is True: Sporadic cases may occur at any time.

Pearl Question 3 (T/F): Congenital heart disease, congestive heart failure, prematurity, immunosuppression, bronchopulmonary dysplasia, and other chronic lung diseases all place a patient in a high-risk category for severe bronchiolitis.

The correct answer is True: Presence of any of these conditions warrants consideration of admission. Closer follow-up care for discharged patients and higher level of care as inpatients should be considered for children with respiratory syncytial virus (RSV) and any of these underlying problems.

Pearl Question 4 (T/F): Adults may become infected with respiratory syncytial virus (RSV).

The correct answer is True: Only elderly people or those with other severe lung disease are likely to become compromised. Otherwise, symptoms resemble those of viral upper respiratory infections.

BIBLIOGRAPHY

Section 11 of 11

• American Academy of Pediatrics: Reassessment of the indications for ribavirin therapy in respiratory syncytial virus infections. American Academy of Pediatrics Committee on Infectious Diseases. Pediatrics 1996 Jan; 97(1): 137-40[Medline].
• American Academy of Pediatrics: Respiratory syncytial virus immune globulin intravenous: indications for use. American Academy of Pediatrics Committee on Infectious Diseases, Committee on Fetus and Newborn. Pediatrics 1997 Apr; 99(4): 645-50[Medline].
• Antonow JA, Hansen K, McKinstry CA, Byington CL: Sepsis evaluations in hospitalized infants with bronchiolitis. Pediatr Infect Dis J 1998 Mar; 17(3): 231-6[Medline].
• Cade A, Brownlee KG, Conway SP, et al: Randomised placebo controlled trial of nebulised corticosteroids in acute respiratory syncytial viral bronchiolitis. Arch Dis Child 2000 Feb; 82(2): 126-30[Medline].
• CDC: Update: Respiratory syncytial virus surveillance--United States, 1997-1998. MM WR Morb Mortal Wkly Rep 1997; 46(49): 1163-5.
• De Boeck K, Van der Aa N, Van Lierde S, et al: Respiratory syncytial virus bronchiolitis: a double-blind dexamethasone efficacy study. J Pediatr 1997 Dec; 131(6): 919-21[Medline].
• Flores G, Horwitz RI: Efficacy of beta2-agonists in bronchiolitis: a reappraisal and meta-analysis. Pediatrics 1997 Aug; 100(2 Pt 1): 233-9[Medline].
• Henderson FW, Clyde WA, Collier AM, et al: The etiologic and epidemiologic spectrum of bronchiolitis in pediatric practice. J Pediatr 1979 Aug; 95(2): 183-90[Medline].
• IMpact--RSV Study Group: Palivizumab, a humanized respiratory syncytial virus monoclonal antibody, reduces hospitalization from respiratory syncytial virus infection in high-risk infants. The IMpact-RSV Study Group. Pediatrics 1998 Sep; 102(3 Pt 1): 531-7[Medline].
• Kellner JD, Ohlsson A, Gadomski AM, Wang EE: Efficacy of bronchodilator therapy in bronchiolitis. A meta-analysis. Arch Pediatr Adolesc Med 1996 Nov; 150(11): 1166-72[Medline].
• Klassen TP, Sutcliffe T, Watters LK, et al: Dexamethasone in salbutamol-treated inpatients with acute bronchiolitis: a randomized, controlled trial. J Pediatr 1997 Feb; 130(2): 191-6[Medline].
• Lowther SA, Shay DK, Holman RC, et al: Bronchiolitis-associated hospitalizations among American Indian and Alaska Native children. Pediatr Infect Dis J 2000 Jan; 19(1): 11-7[Medline].
• McConnochie KM, Roghmann KJ: Predicting clinically significant lower respiratory tract illness in childhood following mild bronchiolitis. Am J Dis Child 1985 Jun; 139(6): 625-31[Medline].
• Outwater KM, Crone RK: Management of respiratory failure in infants with acute viral bronchiolitis. Am J Dis Child 1984 Nov; 138(11): 1071-5[Medline].
• Parrott RH, Kim HW, Arrobio JO, et al: Epidemiology of respiratory syncytial virus infection in Washington, D.C. II. Infection and disease with respect to age, immunologic status, race and sex. Am J Epidemiol 1973 Oct; 98(4): 289-300[Medline].
• Schuh S, Johnson D, Canny G, et al: Efficacy of adding nebulized ipratropium bromide to nebulized albuterol therapy in acute bronchiolitis. Pediatrics 1992 Dec; 90(6): 920-3[Medline].
• Shay DK, Holman RC, Newman RD, et al: Bronchiolitis-associated hospitalizations among US children, 1980-1996. JAMA 1999 Oct 20; 282(15): 1440-6[Medline].
• Sigurs N, Bjarnason R, Sigurbergsson F: Respiratory syncytial virus bronchiolitis in infancy is an important risk factor for asthma and allergy at age 7. Am J Respir Crit Care Med 2000 May; 161(5): 1501-7[Medline].
• Spencer N, Logan S, Scholey S, Gentle S: Deprivation and bronchiolitis. Arch Dis Child 1996 Jan; 74(1): 50-2[Medline].
• Taber LH, Knight V, Gilbert BE, et al: Ribavirin aerosol treatment of bronchiolitis associated with respiratory syncytial virus infection in infants. Pediatrics 1983 Nov; 72(5): 613-8[Medline].
• van Woensel JB, Wolfs TF, van Aalderen WM, et al: Randomised double blind placebo controlled trial of prednisolone in children admitted to hospital with respiratory syncytial virus bronchiolitis. Thorax 1997 Jul; 52(7): 634-7[Medline].
• van Woensel JB, Kimpen JL, Sprikkelman AB, et al: Long-term effects of prednisolone in the acute phase of bronchiolitis caused by respiratory syncytial virus. Pediatr Pulmonol 2000 Aug; 30(2): 92-6[Medline].
• Wang EE, Law BJ, Stephens D: Pediatric Investigators Collaborative Network on Infections in Canada (PICNIC) prospective study of risk factors and outcomes in patients hospitalized with respiratory syncytial viral lower respiratory tract infection. J Pediatr 1995 Feb; 126(2): 212-9[Medline].
• Weber MW, Mulholland EK, Greenwood BM: Respiratory syncytial virus infection in tropical and developing countries. Trop Med Int Health 1998 Apr; 3(4): 268-80[Medline].

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