2. Learning outcome
• By the end of the lesson the learner will be able to understand
• BRONCHIOLITIS
3. Definition:
• Bronchiolitis is an acute, infectious, inflammatory disease of the
upper and lower respiratory tract that results in obstruction of the
small airways
4. Definition:
• The definition for most clinical studies is the first episode of wheezing
in a child younger than 12 to 24 months who has physical findings of
a viral infection and has no other explanation for the wheezing, such
as pneumonia or atopy
5. Definition:
• The broader definition is a wheezing illness due to primary infection
or reinfection with a viral or bacterial pathogen, resulting in
inflammation of the small airways or bronchioles.
6. Etiology:
• Respiratory syncytial virus (RSV) is the most common cause; less
common causes include rhinovirus, parainfluenza virus, influenza
virus, human metapneumovirus, coronavirus, and human bocavirus
(discovered in 2005).
7. :Etiology:
• RSV causes 20-40% of all cases and 44% of cases involving children
younger than 2 years.
• Parainfluenza virus causes 10-30% of all bronchiolitis cases.
• Adenovirus accounts for 5-10% of cases of bronchiolitis.
• Influenza virus accounts for 10-20% of cases of bronchiolitis.
8. Etiology:
• Mycoplasma pneumoniae accounts for 5-15% of cases of
bronchiolitis, particularly among older children and adults.
• Two respiratory syncytial virus (RSV) subtypes, A and B, have been
identified, with subtype A causing most severe infections.
9. Etiology:
• The disease is highly contagious.
• Viral shedding in nasal secretions continues for 6-21 days after
development of symptoms.
• The incubation period is 2-5 days.
10. Epidemiology
• Bronchiolitis typically affects infants younger than 2 years, principally
during the winter months
• Bronchiolitis has a peak incidence between 2 and 6 months of age
and remains a significant cause of respiratory disease during the first
five years of life
11. Epidemiology
• Bronchiolitis is a leading cause of hospitalization in infants and young
children
• Sex: Boys are affected more than girls
• Age: RSV bronchiolitis clearly is a significant disease of the young
child
12. Epidemiology
• RSV infection may be life threatening to older children and adults
undergoing organ and bone marrow transplantation because of the
increasing use of treatment modalities that compromise cellular
immunity.
14. Risk factors
• Chronic lung disease, particularly bronchopulmonary dysplasia,
• Severe congenital or acquired neurologic disease,
• Congenital heart disease with pulmonary hypertension,
• Congenital or acquired immune deficiency diseases.
15. Pathophysiology:
• Viruses penetrate the terminal bronchiolar epithelial cells, causing
direct damage and inflammation in the small bronchi and
bronchioles.
• Necrosis of the respiratory epithelium is one of the earliest lesions in
bronchiolitis.
16. Pathophysiology:
• Proliferation of goblet cells results in excessive mucus production,
while epithelial regeneration with nonciliated cells impairs
elimination of secretions.
17. Pathophysiology:
• Lymphocytic infiltration may result in submucosal edema.
• The pathology results in obstruction of bronchioles by inflammation,
edema, and debris, leading to hyperinflation, increased airway
resistance, atelectasis, and ventilation-perfusion mismatching.
18. Pathophysiology:
• Recovery begins with regeneration of bronchiolar epithelium after 3-4
days, but cilia do not appear for up to 2 weeks.
• Mucus plugs are removed by macrophages.
19. Clinical manifestations
• Bronchiolitis is a constellation of clinical symptoms and signs that
includes a viral upper respiratory prodrome followed by increased
respiratory effort and wheezing in children younger than 2 years of
age
• The typical presentation is acute onset of tachypnea, cough,
rhinorrhea, and expiratory wheezing.
20. Clinical manifestations
• The usual course of RSV bronchiolitis is 1-2 days of fever, rhinorrhea,
and cough, followed by wheezing, tachypnea, and respiratory
distress.
• Typically the breathing pattern is shallow, with rapid respirations.
• Nasal flaring, cyanosis, retractions, and rales may be present, along
with prolongation of the expiratory phase and wheezing, depending
on the severity of illness
21. Clinical manifestations
• Diagnosis is based on the age and seasonal occurrence, tachypnea,
and the presence of profuse coryza and fine rales and/or wheezes on
auscultation of the lungs.
• Hypoxia is the best predictor of severe illness and correlates best with
the degree of tachypnea.
•
22. Diagnosis:
• The peripheral white blood cell count may be normal or may show a
mild lymphocytosis
• Chest x-ray findings typically include hyperinflation with mild
interstitial infiltrates, but segmental atelectasis is common.
23. Differential diagnosis
• Bronchiolitis must be distinguished from a variety of acute and
chronic conditions.
• These include viral-triggered asthma,
• virus-induced wheezing, pneumonia,
• chronic lung disease, foreign body aspiration,
• gastroesophageal reflux,
• congenital heart disease, heart failure, and vascular rings
•
25. Supportive care:
• Initial management includes an assessment of oxygenation and
ventilation and,
• if hypoxemia is present administration of supplemental oxygen.
• Supportive care in both the outpatient and inpatient settings includes
respiratory support and maintenance of adequate fluid intake.
• Saline nose drops and nasal bulb suction may help to relieve partial
nasal obstruction.
26. Respiratory support:
• Respiratory support: Warmed, humidified oxygen should be provided
by nasal canula, head box, or tent to maintain the arterial oxygen
saturation above 92 percent
27. Fluid administration
• : Parenteral fluid administration may be necessary to ensure
adequate hydration and avoid the risk of aspiration in infants and
children with bronchiolitis
• Intravenous fluids should be given as required, avoiding fluid overload
and pulmonary edema.
• .
28. Fluid administration
• Progressive respiratory distress (including progressive hypoxemia and
hypercapnia) and apnea are common indications for admission to the
intensive care unit and mechanical ventilation
29. Pharmacologic therapy
• Bronchodilators: We suggest that infants and children with bronchiolitis
receive a trial of inhaled bronchodilators.
• Inhaled bronchodilators: Although widely used and studied, the efficacy of
inhaled bronchodilators (albuterol, salbutamol, and epinephrine) in the
treatment of bronchiolitis is uncertain; the published results have been
variable
30. Pharmacologic therapy
• Corticosteroids: The antiinflammatory effect of corticosteroids is thought to
reduce airway obstruction by decreasing bronchiolar swelling.
• Whether corticosteroids provide benefit in different subgroups of children
with bronchiolitis is uncertain.
31. Pharmacologic therapy
• Ribavirin: Susceptibility to RSV in high-risk children is reduced by RSV
intravenous immune globulin (RSV-IVIG) or palivizumab, an injectable
monoclonal antibody to RSV F glycoprotein.
• In patients with severe bronchiolitis due to RSV, antiviral therapy may play a
role.
32. Ribavirin:
• Although ribavirin is a nucleoside analogue with good in vitro activity
against RSV, studies examining its effect in children have been
conflicting and the cost for a course of therapy is substantial.
33. Pharmacologic therapy
• RSV infection may permit early intervention with antiviral therapy
(ribavirin), especially in children with marked respiratory distress or
chronic cardiopulmonary disease.
• Children under age 6 weeks and those with underlying metabolic,
neurologic, or congenital abnormalities should also be considered for
ribavirin therapy.
34. Pharmacologic therapy
• Antibiotics: In children with bronchiolitis, antibacterial medications are
warranted only when there are specific indications of a coexisting bacterial
infection (e.g. positive urine culture, acute otitis media, consolidation on
chest radiograph)
•
35. Complications:
• Major concerns include not only the acute effects of bronchiolitis but
also the possible development of chronic airway hyper reactivity
(asthma).
• Bronchiolitis due to RSV infection contributes substantially to
morbidity and mortality in children with underlying cardiopulmonary
disorders, including bronchopulmonary dysplasia,
