Bronchiolitis

Bronchiolitis is an acute viral infection of the small airways (bronchioles), primarily affecting infants and children under 2 years old. It peaks between 2–6 months and is most common in winter or rainy seasons.

How It Develops
• Caused by a virus (most often RSV, but also rhinovirus, adenovirus, parainfluenza, and others).
• The infection inflames and swells bronchioles, leading to mucus buildup and airway narrowing.
• This causes breathing difficulties, wheezing, and cough.

Key Risk Factors
• Age under 2 years, especially under 3 months
• Premature birth
• Underlying heart or lung conditions, weakened immunity
• Exposure to tobacco smoke or crowded environments
• Not being breastfed, attending daycare, or having older siblings

Symptoms & Progression
Symptoms start like a cold (runny nose, mild fever, cough), then may worsen with increased cough, wheezing, rapid or labored breathing, nasal flaring, and chest retractions. Poor feeding and dehydration are common. Most children recover in 5–7 days, though cough and wheeze can linger for weeks. Severe cases can lead to respiratory distress, apnea, or very rarely, respiratory failure.

Diagnosis
Clinically diagnosed through history and physical exam, focusing on breathing sounds and distress. Tests like viral swab, chest X-ray, or pulse oximetry are used only if symptoms are severe or atypical.

Treatment & Care
Supportive care is the mainstay:
• Ensure hydration and nutrition
• Relieve nasal congestion with saline drops and suction
• Administer oxygen if blood oxygen is low
• Use humidified air and, occasionally, nebulized saline in hospitalized infants
• Fever may be managed with age-appropriate acetaminophen or ibuprofen
Antibiotics, steroids, and bronchodilators are not routinely recommended. Hospitalization is needed for severe dehydration or breathing issues; some infants may require non-invasive or mechanical ventilation. A monoclonal antibody (palivizumab or nirsevimab) is used preventively for high-risk babies during RSV season.

Prevention & Self-care
• Frequent handwashing and cleaning shared surfaces
• Keep sick individuals away from infants
• Avoid exposing babies to cigarette smoke
• Promote breastfeeding
• Immunize pregnant individuals and vulnerable infants against RSV where available

Prognosis & Impact
Most children recover fully without lasting effects. A small proportion (about 2–3%) require hospitalization; serious complications are rare in healthy infants. However, it’s a leading cause of hospitalization in infants globally—especially in low- and middle-income countries—with hundreds of thousands of hospitalizations and deaths annually. Follow-up is advised for recurrent wheezing.