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 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.
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.