Bronchiolitis: Definition and Clinical Presentation

Study Notes

Definition and Etiology

Bronchiolitis is a common viral infection of the lower respiratory tract, mostly affecting infants and young children.
It typically occurs during fall and winter months.
The most common cause is Respiratory Syncytial Virus (RSV).
Other viruses, like rhinoviruses, influenza viruses, and parainfluenza viruses, can also cause bronchiolitis.
The infection primarily targets the bronchioles (small airways) in the lungs, leading to inflammation and airway narrowing.

Clinical Presentation

Common symptoms include runny nose, cough (often worse at night), wheezing, difficulty breathing (including rapid breathing, chest retractions, and nasal flaring), and fever (not always present).
Symptoms develop gradually, worsening over 2-3 days to a week, then improving.
Severe cases cause significant respiratory distress, needing hospitalization.

Diagnosis

Diagnosis relies on clinical presentation and history.
A physical exam, including listening to lung sounds, assessing breathing effort, and observing symptoms, is crucial.
Laboratory tests, such as a complete blood count (CBC), can rule out other conditions.
Chest X-rays or CT scans aren't usually needed for mild to moderate cases.
A rapid antigen test for RSV can quickly confirm RSV presence, though not always necessary for treatment.

Management

Supportive care is the primary treatment for bronchiolitis.
This involves monitoring respiratory distress (including oxygen saturation), adequate hydration (oral or intravenous fluids), symptom management (with limited effectiveness of decongestants), and oxygen therapy when needed.
Close monitoring is essential for infants and toddlers, especially for respiratory status decline.
Hospitalization is often needed for severe symptoms, such as severe respiratory distress, low oxygen levels, or poor feeding.
Antiviral medications aren't routinely used, except in specific cases determined by a healthcare professional.

Prevention

Hand hygiene is critical.
Practicing respiratory hygiene and cough etiquette is important.
Limiting contact with those showing respiratory symptoms is helpful.
RSV vaccination is available, mainly for high-risk groups like infants and older adults with pre-existing lung conditions.
Respiratory syncytial virus (RSV) immunoglobulin (IVIG) therapy is a treatment choice for severely affected infants and children.

Prognosis and Complications

Most bronchiolitis cases resolve within a few weeks.
Potential complications include pneumonia (lung infection), secondary bacterial infections, apnea (breathing cessation), and bronchiolitis obliterans (a rare, chronic lung condition).
While typically self-limiting, medical attention is important for infants and young children with noticeable symptoms, as complications are a concern.
Generally, a positive prognosis is expected for healthy children.

Associated Risk Factors

Prematurity is a significant risk factor for severe bronchiolitis.
Underlying medical conditions (especially those affecting the respiratory or immune system) increase the risk.
Contact with children showing respiratory illness increases risk exposure.
Younger age (especially under 6 months) within the first bronchiolitis season increases the chance of hospitalization.

Description

This quiz covers the definition, etiology, and clinical presentation of bronchiolitis, a common viral infection affecting infants. Learn about the symptoms, causative agents, and the typical progression of the disease. Perfect for healthcare students or anyone interested in pediatric healthcare.