1. Bronchiolitis is most commonly caused by respiratory syncytial virus (RSV) in infants and young children, causing inflammation in the small airways. 2. It typically presents with cough, wheezing, nasal congestion and difficulty breathing. Chest radiographs may show hyperinflation of the lungs. 3. Treatment is supportive with oxygen and monitoring since most cases resolve on their own. Hospitalization is needed for moderate to severe distress, hypoxemia or apnea. While recurrence is common, bronchiolitis often improves within a week.

1. Bronchiolitis
Jwan Ali AlSofi

2. 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.

3. Definition:-
• Bronchiolitis is a disease of small bronchioles with
increased mucus production and occasional
bronchospasm, sometimes leading to airway obstruction.
• It is an acute viral lower respiratory tract infection.
• Bronchiolitis is most commonly seen in infants and young
children.
• Most severe cases occurring among infants.
• Respiratory syncytial virus (RSV) is a primary cause of
bronchiolitis.
• Bronchiolitis is potentially life-threatening.

7. ① Respiratory syncytial virus (RSV) – is a primary cause of
bronchiolitis
② Human metapneumovirus.
③ Parainfluenza viruses.
④ Pnfluenza viruses.
⑤ Adenoviruses.
⑥ Rhinoviruses.
⑦ Coronaviruses.
⑧ Mycoplasma pneumoniae.
Etiology:-

8. • 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.
Transmission:-

9. Children who are at increased risk of
severe, potentially fatal disease, include:-
1. premature infants
2. children with chronic lung disease of prematurity,
3. hemodynamically significant congenital heart disease,
4. neuromuscular weakness,
5. immunodeficiency
9

10. Epidemiology:-
• Bronchiolitis is the most common serious respiratory infection
of infancy.
• 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.

11. • Bronchiolitis classically presents as a progressive respiratory
illness .
• 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 raspy breathing.
② Audible wheezing.
③ Low-grade fever.
④ Irritability – may reflect the increased work of breathing
⑤ Decreased oral intake.
• Young infants infected with RSV may have apnea as the first
sign of infection.
Clinical Manifestations:-

12. • Physical signs include :
① Nasal flaring.
② Suprasternal and Intercostal retractions.
③ Air trapping with hyperexpansion of the lungs.
④ percussion of the chest usually reveals only hyperresonance
⑤ Prolongation of the expiratory phase of breathing
⑥ Diffuse Wheezing and crackles throughout the breathing cycle.
⑦ Poorly audible breath sounds suggest severe disease with nearly
complete bronchiolar obstruction.
⑧ With more severe disease, grunting and cyanosis may be present.
Clinical Manifestations:-

16. The natural
history of
bronchiolitis:-

17. Happy wheezer:-
• Bronchiolitis, when noted in an otherwise healthy child beyond
age 3 months, is often called the “disease of the happy
wheezer,” where the child demonstrates considerable cough and
wheezing while generally appearing only mildly ill.
17

18. 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 / PCR of nasopharyngeal secretions for RSV,
parainfluenza viruses, influenza viruses, and adenoviruses are
sensitive tests to confirm the infection.

19. • Chest radiographs frequently show signs of lung
hyperinflation, including :
① Increased lung lucency.
② Flattened or depressed diaphragms.
• Areas of increased density may represent:-
1. viral pneumonia
2. localized atelectasis.
Laboratory and Imaging:-

20. Differential Diagnosis:-
•Asthma :
①Age of presentation.
②Presence of fever.
③Absence of personal or family history of
asthma.

21. Bronchiolitis Asthma
< 2 years > 2 years
Fever
No fever, unless a RTI is the
trigger for the asthma
exacerbation.
Viral URI symptoms
preceding presentation
Sudden onset of symptoms
No allergy triad Allergic history
Absence of personal or
family history of asthma
Presence of personal or
family history of asthma
Response to
bronchodilators – negative
Response to
bronchodilators – positive

22. • Airway foreign body.
▫ Suggested by a focal area on radiography that remains
inflated despite changes in position
• Cystic fibrosis.
▫ is associated with poor growth, chronic diarrhea, and a
positive family history.
• GERD.
▫ Wheezing is likely to be chronic or recurrent, and the
patient may have a history of frequent emesis.
• Cardiogenic asthma.
▫ Is wheezing associated with pulmonary congestion
secondary to left-sided heart failure.
• Congenital airway obstructive lesion.
• Exacerbation of chronic lung disease.
• Viral or bacterial pneumonia.
Differential Diagnosis:-

23. Treatment:-
•Supportive therapy :
① Oxygen administration, if needed.
② Respiratory monitoring for apnea
③ Control of fever.
④ Hydration.
⑤ Upper airway suctioning.
⑥ Bronchodilators, corticosteroids, chest physiotherapy,
and hypertonic saline are seldom effective and are not
generally recommended.
⑦ Antibiotics should be avoided unless there is strong
suspicion for concomitant bacterial infection.

24. • 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.
Treatment:-

25. 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.

26. • 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.
• Rarely, following adenovirus infection, the illness may
result in permanent damage to the airways (bronchiolitis
obliterans).
Complications and Prognosis

27. 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.
• Immunization with influenza vaccine is recommended
for all children older than 6 months and may prevent
influenza-associated disease.

28. Reference