Acute bronchiolitis

By: Hisham Alrabty(pediatrics
consultant).
drhishamalrabty-10-4-2014

WHAT IS ACUTE
BRONCHIOLITIS?
Bronchiolitis is an acute
inflammatory injury of the
bronchioles that is usually caused by
a viral infection (most commonly
respiratory syncytial virus and
human metapneumovirus).

EPIDEMIOLOGY:
Bronchiolitis is a significant cause of respiratory
disease worldwide.
According to WHO bulletin, an estimated 150
million new cases occur annually.
About 75% of cases of bronchiolitis occur in
children younger than 1 year and 95% in children
younger than 2 years.
Incidence peaks in those aged 2-8 months.
Bronchiolitis as 1.25 times more common in
males than in females.
Death is 1.5 times more likely in males.
Lower socioeconomic status may increase the
likelihood of hospitalization.

WHAT CAUSES
BRONCHIOLITIS?
Typically caused by viruses
1. RSV-most common(64%).
2. Para influenza.
3. Human Metapneumovirus(9-30%).
4. Influenza(6%).
5. Rhinovirus(16%).
6. Adenovirus.
Occasionally associated with
Mycoplasma pneumonia infection

RSV:
 RSV causes 20-40% of all cases and 44% of
cases that involve children younger than 2
years.
 Two RSV subtypes, A and B, have been
identified on the basis of structural
variations in the G protein.
 Subtype A causes the most severe
infections.
 One subtype or the other usually
predominates during a given season; thus,
RSV disease has “good” and “bad” years.
 Viral shedding in nasal secretions continues
for 6-21 days after symptoms develop. The
incubation period is 2-5 days.

PATHOPHYSIOLOGY:
Bronchiolar injury and the consequent
interplay between inflammatory and
mesenchymal cells can lead to diverse
pathologic and clinical features:
 Increased mucus secretion.
 Bronchial obstruction and constriction.
 Alveolar cell death, mucus debris, viral
invasion.
 Air trapping.
 Atelectasis.
 Reduced ventilation that leads to ventilation-
perfusion mismatch.

RISK FACTORS :
for the development of bronchiolitis include the
following :
 Low birth weight, particularly premature infants.
 Lower socioeconomic group.
 Crowded living conditions, daycare, or both.
 Parental smoking.
 Chronic lung disease, particularly bronchopulmonary
dysplasia.
 Severe congenital or acquired neurologic disease.
 Congenital heart disease (CHD) with pulmonary
hypertension.
 Congenital or acquired immune deficiency diseases.
 Age less than 3 months.
 Airway anomalies.

CLINICAL PRESENTATION:
 Begin with upper respiratory tract
symptoms:
nasal congestion, rhinorrhea, mild cough,
low-grade fever.
 Progress in 3-6 days to rapid respirations,
chest retractions, wheezing.
 Tachypnea.
 Prolonged expiratory phase, rhonchi,
wheezes and crackles.
 Possible dehydration.
 Possible conjunctivitis or otitis media.
 Possible cyanosis or apnea.

DIAGNOSIS:
 diagnosis is based on history and
physical exam on other words it is
clinical diagnosis.
CBC could show lymphocytosis.
ABG for hypoxia and hypercapnia.
CxR shows hyper inflated chest and
atelectasis.
Rapid antigen detection for RSV,
Para influenza, influenza, adenovirus
(sensitivity 80-90%).
Immunofluorescence for viral
detection and viral culture,PCR.

DIFFERENTIAL DIAGNOSIS:
1. Pneumonia viral and
bacterial.
2. Asthma.
3. FB aspiration.
4. Pulmonary edema( a
cyanotic CHD).
5. Gastroesophygeal reflux.

ADMISSION CRITERIA:
 Persistent resting oxygen saturation below 92% in
room air.
 Markedly elevated respiratory rate (>70-80
breaths/min).
 Dyspnea and intercostal retractions, indicating
respiratory distress.
 cyanosis.
 Chronic lung disease.
 Congenital heart disease.
 Prematurity.
 Age younger than 3 months, when severe disease is
most common.
 Inability to maintain oral hydration in patients
younger than 6 months.
 Parent unable to care for child at home.

TREATMENT:
Among many medications and
interventions used to treat
bronchiolitis, thus far, only
oxygen appreciably improves the
condition of young children.
Therefore, therapy is directed
toward symptomatic relief and
maintenance of hydration and
oxygenation.

NONPHARMACOTHERAPY:
Supportive care for patients with
bronchiolitis may include the following:
Supplemental humidified oxygen.
Maintenance of hydration.
Mechanical ventilation.
Nasal and oral suctioning.
Apnea and cardiorespiratory
monitoring.
Temperature regulation in small
infants.

PHARMACOTHERAPY:
Medications have a limited role in the
treatment of bronchiolitis.
Healthy children with bronchiolitis usually
have limited disease and usually do well with
supportive care only.
The following medications are used in
selected patients with bronchiolitis:
 Alpha/beta agonists (eg, racemic
epinephrine, albuterol).
 Monoclonal antibodies (eg, palivizumab).
 Antiviral agents (eg, ribavirin).

GUIDELINES FOR TREATMENT:
In 2006, the AAP, in conjunction
with the American Academy of
Family Physicians (AAFP), the
American College of Chest
Physicians (ACCP), and the
American Thoracic Society (ATS),
published the following
recommendations :

1. Diagnosis and severity should be based on history and
physical findings.
2. Bronchodilators should not be routinely used.
3. Corticosteroids should not routinely be used.
4. Ribavirin should not be used routinely.
5. Antibacterials should be used only upon proven
coexistence of bacterial infection.
6. Hydration and the ability to take oral fluids should be
assessed
7. Supplemental oxygen should be supplied for saturations
below 90% on pulse oximetry.
8. Palivizumab prophylaxis should be administered to
selected children
9. Hand decontamination is indicated to prevent nosocomial
spread.
10. Infants should not be exposed to secondary smoking, and
breastfeeding is recommended.
11. Clinicians should inquire about use of complementary and
alternative medicine therapies.

ALPHA/BETA AGONISTS:
studies have reported that their use ranges
from approximately 50% of cases to more than
90%.
They act by decreasing muscle tone in both
small and large airways in the lungs, thus
increasing ventilation.
Most controlled studies have failed to show a
benefit in terms of oxygen saturation, rate of
hospitalization, or length of hospital stay.
Some studies showed salbutamol better than
adrenaline and other studies showed the
opposite.

RIBAVIRIN:
 It is a synthetic nucleoside analogue that
resembles guanosine and inosine.
 It is believed to act by interfering with
expression of messenger RNA and inhibiting
viral protein synthesis.
 Ribavirin appears safe but is expensive.
 Its efficiency and effectiveness have not
been clearly demonstrated in large,
randomized, placebo-controlled trials.
 At present, routine use of ribavirin cannot
be recommended.

CHEST PHYSIOTHERAPY:
A 2012 Cochrane review, which included
9 studies of children younger than 2
years with acute bronchiolitis,
confirmed that chest physiotherapy
does not decrease the severity of the
disease, improve respiratory
parameters, shorten the hospital stay,
or reduce oxygen requirements in
nonventilated hospitalized patients.

HYPERTONIC SALINE AS TREATMENT:
A Randomized Trial of Nebulized 3% Hypertonic
Saline With Epinephrine in the Treatment of Acute
Bronchiolitis in the Emergency Department.
Simran Grewal, MD; Samina Ali, MD; Don W. McConnell,
MD; Ben Vandermeer, MSc; Terry P. Klassen, MSc, MD.
Conclusion:
in the treatment of acute bronchiolitis, hypertonic
saline and epinephrine did not improve clinical outcome
any more than normal saline and epinephrine in the
emergency setting.
This differs from previously published results of
outpatient and inpatient populations and merits further
evaluation.

Nebulized hypertonic saline solution for acute
bronchiolitis in infants.
Zhang L1, Mendoza-Sassi RA, Wainwright C,
Klassen TP- 2013 Jul 31.
Conclusion:
Current evidence suggests nebulized 3% saline
may significantly reduce the length of hospital
stay among infants hospitalized with non-
severe acute viral bronchiolitis and improve the
clinical severity score in both outpatient and
inpatient populations.

PREVENTION:
 Palivizumab is a humanized monoclonal
antibody directed against the F
(fusion) protein of RSV.
 Given monthly through the RSV
season 15 mg/kg IM q1Month ,
 it has been demonstrated to decrease
chances of RSV hospitalization in
premature babies who are at increased
risk for severe RSV-related illness.

Acute bronchiolitis

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