Bronchiolitis in Paediatrics

Prepared bymalek ahmad

University of malaya

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

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

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

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

Clinical presentationHistory Coryza

– rhinorrhea, fever

Dry cough

Progressive

breathlessne

ss

Wheezing Feedi

ng difficu

lty

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

Differential diagnosis

Aspiration syndrome Asthma

Pertussis (bronchitis) Pneumonia

Investitigation

FBC •Lymphocytosis

Nasopharyngeal swab/ nasal wash

•To detect RSA antigen in epithelial cell from secretion•Direct immunofluorescent antibody (IFA) staining or ELISA, PCR

Chest Xray •Hyperinflated lung due to airways obstruction, air trapping and focal atelectasis (arterial desaturation)•Increased interstitial marking and peribronchiol cuffing

Blood gas analysis •In severe cases show lowered arterial oxygen and raised CO2 tension

ECG, ECHO •May display arrhythmias or cardiomegaly

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

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

Bronchitis (whooping cough / pertussis) Highly infectious caused by bordetella 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)

Phases

• 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

Investigation

• Culture of nasal swab• FBC: marked lymphocytosis

Treatment and management

• Erythromycin for eradicates organism, closed contact and prophylaxis• Immunisation reduce risk developed pertussis but not 100%