Bronchiolitis
Abdullah M. Al-Olayan
MBBS, SBP, ABP.
Assistant Professor of Pediatrics.
Pediatric Pulmonologist.
Objectives
① Discuss the epidemiology, etiology and
clinical manifestations of acute
bronchiolitis.
② Discuss the differential diagnosis.
③ Discuss the diagnostic evaluation for
recurrent wheezing.
④ Discuss the treatment of acute
bronchiolitis.
Etiology
 Bronchiolitis is a disease of small bronchioles
with increased mucus production and
occasional bronchospasm, sometimes
leading to airway obstruction.
 Bronchiolitis is most commonly seen in infants
and young children.
 Respiratory syncytial virus (RSV) is a primary
cause of bronchiolitis.
Etiology
 Other causative organisms :
① Human metapneumovirus.
② Parainfluenza viruses.
③ Pnfluenza viruses.
④ Adenoviruses.
⑤ Rhinoviruses.
⑥ Coronaviruses.
⑦ Mycoplasma pneumoniae.
Etiology
 Viral bronchiolitis is extremely contagious
and is spread by contact with infected
respiratory secretions.
 Hand carriage of contaminated
secretions is the most frequent mode of
transmission.
Epidemiology
 Bronchiolitis is a leading cause of
hospitalization of infants.
 Bronchiolitis occurs almost exclusively during
the first 2 years of life.
 Peak age at 2 to 6 months.
 In the US, annual peaks are usually in the late
winter months from December through
March.
Clinical Manifestations
 Bronchiolitis caused by RSV has an incubation
period of 4 to 6 days.
 its early phase started by cough and rhinorrhea.
 It progresses over 3 to 7 days to :
① Noisy, and rapid breathing.
② Audible wheezing.
③ Low-grade fever.
④ Irritability.
⑤ Decreased oral intake.
Clinical Manifestations
 Young infants infected with RSV may have apnea
as the first sign of infection.
 Physical signs include :
① Wheezing and crackles with Prolongation of
the expiratory phase
② Nasal flaring.
③ Suprasternal and Intercostal retractions.
④ Air trapping with hyperexpansion of the lungs.
⑤ With more severe disease, grunting and
cyanosis may be present.
Laboratory and Imaging
 Routine laboratory tests are not required to
confirm the diagnosis.
① Pulse oximetry is adequate for monitoring
oxygen saturation.
② Frequent, regular assessments and
cardiorespiratory monitoring of infants are
necessary because respiratory failure may
develop.
③ Antigen tests of nasopharyngeal secretions for
RSV, parainfluenza viruses, influenza viruses,
and adenoviruses are sensitive tests to confirm
the infection.
Laboratory and Imaging
 Chest radiographs frequently show signs
of lung hyperinflation, including :
① Increased lung lucency.
② Flattened or depressed diaphragms.
 Areas of increased density may
represent either viral pneumonia or
localized atelectasis.
Differential Diagnosis
 Asthma :
① Age of presentation.
② Presence of fever.
③ Absence of personal or family
history of asthma.
Differential Diagnosis
 Airway foreign body.
 Congenital airway obstructive lesion.
 Cystic fibrosis.
 Exacerbation of chronic lung disease.
 Viral or bacterial pneumonia.
 Cardiogenic asthma.
 GERD.
Treatment
Supportive therapy :
① Oxygen administration, if needed.
② Respiratory monitoring.
③ Control of fever.
④ Hydration.
⑤ Upper airway suctioning.
⑥ Bronchodilators and corticosteroids are
seldom effective and are not generally
recommended.
Treatment
 Indications for hospitalization :
① Moderate to marked respiratory distress.
② Hypoxemia.
③ Apnea.
④ Inability to tolerate oral feeding.
⑤ Lack of appropriate care available at
home.
⑥ High-risk children.
Complications and
Prognosis
 Most hospitalized children show marked
improvement in 2 to 5 days.
 Tachypnea and hypoxia may progress to
respiratory failure requiring assisted
ventilation.
 Most cases of bronchiolitis resolve
completely.
 Recurrence is common but tends to be
mild and should be assessed and
treated similarly to the first episode.
Complications and
Prognosis
 The incidence of asthma seems to be higher
for children hospitalized for bronchiolitis as
infants.
 There is a 1% to 2% mortality rate, highest
among infants with preexisting
cardiopulmonary or immunologic
impairment.
Prevention
 Monthly injections of palivizumab, an RSV
specific monoclonal antibody.
 Initiated just before the onset of the RSV season.
 Indications :
 Infants under 2 years old with :
① chronic lung disease with prematurity.
② Very low birth weight.
③ Hemodynamically significant cyanotic and
acyanotic congenital heart disease.
Prevention
 Immunization with influenza vaccine is
recommended for all children older than
6 months and may prevent influenzaassociated disease.
Reference