RSV Bronchiolitis

Respiratory syncytial virus bronchiolitis is bronchiolitis caused by respiratory syncytial virus, the leading viral cause of lower respiratory infection and hospitalisation in infants worldwide.

• Nearly all children are infected by age 2 years, and reinfection is common throughout life.
• Epidemics occur seasonally (in the cool rainy season in many tropical regions).
• Spread is by droplets, contaminated surfaces and hands. The virus survives for hours on surfaces.
• Severe disease is commoner in premature babies, young infants, congenital heart disease, chronic lung disease, immunodeficiency, Down syndrome and neuromuscular disease.
• Infection is associated with later recurrent wheeze.

Presentation is a coryzal illness that progresses to lower airway obstruction, with some distinguishing features.

• Rhinorrhoea, cough and low-grade fever progress over 2 to 3 days to tachypnoea, wheeze and crackles.
• Apnoea is a prominent early feature in young and premature infants.
• Poor feeding, irritability and lethargy.
• Conjunctivitis and otitis media may co-exist.
• Severe disease: hypoxia, cyanosis, grunting, nasal flaring and subcostal recession.
• Adults and older children have cold-like illness. The elderly and immunocompromised can develop pneumonia.
• Differential diagnosis: other viral bronchiolitis, pneumonia, pertussis, asthma, heart failure, foreign body and cystic fibrosis.
• Complications: respiratory failure, apnoea, secondary bacterial pneumonia, otitis media, atelectasis, recurrent wheeze, and rare death.

Diagnosis is clinical, with virology where it changes management.

• Assess work of breathing, saturation and hydration.
• Rapid antigen test or polymerase chain reaction on nasopharyngeal aspirate for confirmation, infection control and cohorting.
• Chest X-ray: hyperinflation, patchy atelectasis or consolidation. Needed only if severe or atypical.
• Full blood count and C-reactive protein if secondary bacterial infection is suspected.
• Blood gas in severe disease.

Support is the mainstay.

• Supportive: nasal suction, oxygen for saturation below 92 percent, nasogastric or intravenous fluids if feeding is under half of usual, frequent small feeds, and contact isolation.
• Pharmacological: no routine bronchodilators, corticosteroids or antibiotics. Antibiotics for secondary bacterial infection (amoxicillin-clavulanate 15 mg/kg of amoxicillin component every 8 hours).
• Ribavirin is reserved for severely immunocompromised patients with documented disease and specialist guidance.
• Respiratory support: high-flow nasal oxygen, continuous positive airway pressure, ventilation for respiratory failure.
• Prevention: palivizumab 15 mg/kg intramuscularly monthly (up to 5 doses) for high-risk infants during the season where available; nirsevimab 50 mg (under 5 kg) or 100 mg (5 kg or more) once intramuscularly for infants in their first season; maternal vaccination in late pregnancy where available.
• Hand hygiene, avoiding smoke exposure, breastfeeding, and avoiding contact with sick people.
• Special groups: infants born premature, with congenital heart disease or chronic lung disease should be admitted early. Older children with underlying disease need monitoring.
• Red flags: apnoea, cyanosis, saturation below 92 percent, severe recession, feeding under half of usual, exhaustion and age under 6 weeks.
• Follow-up: discharge when feeding is adequate and saturation stable. Primary care review at 48 hours. Monitor for recurrent wheeze.