Friday, March 29, 2024

Bronchiolitis

Practice Essentials

Bronchiolitis is an acute inflammatory injury of the bronchioles that is usually caused by a viral infection (most commonly respiratory syncytial virus). This condition may occur in persons of any age, but severe symptoms are usually evident only in young infants, as seen in the image below.

A chest radiography revealing lung hyperinflation

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. Image courtesy of Wikipedia Commons.

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Signs and symptoms

Because bronchiolitis primarily affects young infants, clinical manifestations are initially subtle, such as the following:

May become increasingly fussy and have difficulty feeding during the 2 to 5-day incubation period

Low-grade fever (usually < 101.5°F); possible hypothermia in infants younger than 1 month

Increasing coryza and congestion

Apnea: May be the presenting symptom in early disease

Severe cases of bronchiolitis may progress over 48 hours to the following signs and symptoms:

Respiratory distress with tachypnea, nasal flaring, retractions

Irritability

Possibly cyanosis

See Clinical Presentation for more detail.

Diagnosis

The diagnosis of bronchiolitis is based on clinical presentation, the patient’s age, seasonal occurrence, and findings from the physical examination, which may reveal the following:

Tachypnea

Tachycardia

Fever (38-39°C)

Retractions

Fine rales (47%); diffuse, fine wheezing

Hypoxia

Otitis media

Laboratory tests

When the clinical presentation, patient’s age, seasonal occurrence, and findings from the physical examination are consistent with the expected diagnosis of bronchiolitis, few laboratory studies are necessary.
Diagnostic testing is controversial but is typically used to exclude other diagnoses (eg, bacterial pneumonia, sepsis, or congestive heart failure) or to confirm a viral etiology and determine required infection control for patients admitted to the hospital.

Commonly used tests in the evaluation of patients with bronchiolitis include the following:

Rapid viral antigen or nucleic acid amplification testing of nasopharyngeal secretions for respiratory syncytial virus

Arterial blood gas analysis

White blood cell count with differential

C-reactive protein level

Pulse oximetry

Blood cultures

Urine analysis, specific gravity, and culture

Cerebrospinal fluid analysis and culture

Serum chemistries

Electrocardiography or echocardiography should be reserved for those few children who display arrhythmias or cardiomegaly.

Imaging studies

Chest radiographs are not routinely necessary.
A practical approach is to obtain a chest radiograph in children who appear ill, are experiencing clinical deterioration, or are at high risk (eg, those with underlying cardiac or pulmonary disease).

This imaging modality is most useful in excluding unexpected congenital anomalies or other conditions
; it may also yield evidence of alternative diagnoses (eg, lobar pneumonia, congestive heart failure, or foreign body aspiration).

Procedures

In rare situations (eg, severe immunodeficiency, strong history of possible foreign body aspiration), bronchoscopy may be indicated for diagnostic bronchoalveolar lavage or therapeutic foreign body removal.

See Workup for more detail.

Management

Among numerous 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. Otherwise-healthy children with bronchiolitis usually have limited disease and do well with supportive care only.

The following medications are used in selected patients with bronchiolitis:

Alpha/beta agonists (eg, albuterol, racemic epinephrine)

Monoclonal antibodies (eg, palivizumab)

Antibiotics (eg, ampicillin, cefotaxime, ceftriaxone)

Antiviral agents (eg, ribavirin)

Intranasal decongestants (eg, oxymetazoline)

Corticosteroids (eg, dexamethasone, prednisone, methylprednisolone)

See Treatment and Medication for more detail.

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