Bronchiolitis is an inflammatory disease of the small airways caused primarily by Respiratory Syncytial Virus (RSV) in infants under 1 year old. It leads to obstruction of the small airways due to inflammation, mucus production, and edema. Clinically, infants present with rhinorrhea, cough, tachypnea, wheezing and respiratory distress. Chest X-ray may show hyperinflated lungs. Management is supportive with oxygen, hydration and sometimes bronchodilators. Most infants recover within 2 weeks but some may develop long-term wheezing.

1. Bronchiolitis in
Paediatrics
Prepared by
malek ahmad
University of malaya

3. Introduction
Acute infectious inflammatory disease of the URT and
LRT that result in obstruction of the small airways
Occur in all age gp, larger airways of older children
and adults better accommodate mucosal edema,
severe respiratory symptoms limited to young infants
90% are aged 1-9 months (rare after 1 year of age),
boys affected more than girls
Major concern not only the acute effects bronchiolitis
but the possible development of chronic airway
hyperreactivity (asthma)
Infants a affected most often because of their small
airways, high closing volumes, and insufficient
collateral ventilation

5. Aetiological agents
• Isolated agent in 75% of children younger than 2 years and highly contagious
• Enveloped RNA virus that belongs to the Paramyxoviridae family within the
Pneumovirus genus
• Two RSV subtypes A (severe) and B (structural variations in the G protein)
• Viral shedding in nasal secretions for 6-21 days after symptoms develop. IP
=2-5 days
• Complex immunologic mechanisms play a role in RSV bronchiolitis. Type I
allergic reactions mediated by the IgE antibody account for significant
bronchiolitis thus breastfed babies (colostrum-IgA) relatively protected
Respiratory Syncytial Virus (RSV)
Human metapneumovirus, parainfleunze, influenza, rhinovirus, adenovirus
• accounts for 5-15% particularly among older children and adults
Mycoplasma pneumoniae

6. Risk factors
Low birth weight
(PREM)
Lower
socioeconomic gp
Parental smoking
Crowded
condition, daycare
Chronic lung
disease-
bronchopulmonary
dysplasia
CHD + pulmonary
hypertension
<3 months old Aiways anomalies
Congenital/
acquired
immunedeficiency
disease

7. Pathophysiology
Acquisition of infection
Necrosis of respiratory
epithelium (<24h)
Proliferation of goblet
cells > excessive mucus
production
Nonciliated epithelium
cell regeneration >
impaired secretion
elimination (removed
by macrophages)
Lymphocytic infiltration
> submucosal edema
Cytokine and
chemokines released >
Increased cellular
recruitment
Obstruction due to
inflammatory cells
debris + fibrin + mucus +
edema fluid (not due to
bronchoconstriction)
Bronchioles obstruction
lead to hyperinflation +
increase airways
resistance + atelactasis +
V/Q mismatch
Recovery with
bronchiolar epithelium
regeneration after 3-4
days

8. Clinical presentation
History
Coryza –
rhinorrhea, fever
Dry cough
Progressive
breathlessness
Wheezing
Feeding difficulty
Hypothermic (<1
month)
Respiratory distress-
tachypnea, nasal flare,
recession, irritability
and cyanosis
Physical
Sharp and dry
cough
Tachypnoea and
tachycardia
Recession
Hyperinflated chest
– sternum
prominent + liver
displaced
Fine end
inspiratory crackles
High pitched
wheezes-
expiratory >
inspiratory
Cyanosis / pallor

10. Differential diagnosis
Aspiration
syndrome
Asthma
Pertussis
(bronchitis)
Pneumonia

11. Investitigation
• Lymphocytosis
FBC
• To detect RSA antigen in epithelial cell from secretion
• Direct immunofluorescent antibody (IFA) staining or
ELISA, PCR
Nasopharyngeal
swab/ nasal wash
• Hyperinflated lung due to airways obstruction, air
trapping and focal atelectasis (arterial desaturation)
• Increased interstitial marking and peribronchiol cuffing
Chest Xray
• In severe cases show lowered arterial oxygen and raised
CO2 tensionBlood gas analysis
• May display arrhythmias or cardiomegaly
ECG, ECHO

12. A chest
radiography
revealing lung
hyperinflation
with a flattened
diaphragm and
bilateral
atelectasis in
the right apical
and left basal
regions in a 16-
day-old infant
with severe
bronchiolitis

13. Management
Supportive (viral) provide adequate fluid (NG/IV) to maintain hydration and
monitor for apnea (infant)
Humidified O2 delivered via nasl cannulae determined by pulse oximetry
Mist/ antibiotics/ steroids not helpful
Nebulised bronchodilator (salbutamol/ipratropium) often used but not reduce
severity / illness duration
Prophylaxis- good hand hygiene and monoclonal antibody prophylaxis (im
palivizumab)
Prognosis Recover with 2w
Half will have recurrent
cough + wheeze
Following adenovirus
infection > permanent
airways damage
(bronchiolitis
obliterans)

14. Bronchitis (whooping cough / pertussis)
•Inflammation of brochi produce mixture of wheeze and coarse crackles
•Main symptoms: cough(<2w if >2w caused by pertussis/ mycoplasma) and fever
•Complication: pneumonia, convulsion, bronchiectasis and death (infants with apnea)
Highly infectious caused by bordetella pertussis
•Catarrhal phase (1w): coryza
•Paroxysmal phase (3-6w): paroxysmal/spasmodic cough then inspiratory whoop, cough
worse at night + vomit, can go red/blue, mucus flow from nose and mouth, apnea (infant),
epistaxis (nosebleed) and sunconjuctival haemorrhage
•Convalescent phase (persist months): symptoms decrease
Phases
•Culture of nasal swab
•FBC: marked lymphocytosis
Investigation
•Erythromycin for eradicates organism, closed contact and prophylaxis
•Immunisation reduce risk developed pertussis but not 100%
Treatment and management