1. RSV Respiratory Syncytial Virus

2. What is RSV? • A respiratory virus that infects the lungs and breathing passages • Contributes to most cases of Bronchiolitis in young children • Viral-induced lower RTI that occurs almost exclusively in infants and young children • Can contribute to Croup • Acute laryngotracheobronchitis, common in kids 6mo-5 years, caused by a virus like Flu A or RSV • Can be a recurrent problem in children

3. How often does it occur? • Infects nearly 100% of children in the US by 2-3 years of age • Usually occur during fall, winter and early spring

4. Etiology • Cause and site of respiratory infections, such as Bronchiolitis and Croup are due to: • Age of the child • Seasonal variables • Environmental exposures (siblings, daycare)

5. Pathophysiology of RSV Bronchiolitis • RSV –› inflammation & edema of bronchiolar epithelial cells • Membranes of infected cells fuse to adjacent cells –› “syncytia” (mass of cells) • Bronchiole mucosa swells & lumina fills with exudate and mucus • Inflammatory cells infiltrate area –› shedding of dead epithelial cells –› obstruction of small airway passages • Hyperinflation & areas of atelectasis are seen • The inflammation and exudate caused by RSV infection –› bronchiole obstruction during expiration, air trapping, poor gas exchange, increased work of breathing and classic expiratory wheezes

6. Pathophysiology of RSV related Croup • Subglottic edema from viral infection –› upper airway obstruction –› increased resistance to air flow –› increased intrathoracic negative pressure –› collapse of upper airway –› respiratory failure

7. Clinical Presentation of RSV Bronchiolitis • Tachypnea • Expiratory wheezing • Cough • Rhinorrhea • Mild fever • Varying degrees of respiratory distress • CXR: • Hyperexpanded lungs • Patchy or peribronchial infiltrates • Atelectasis of right upper lobe

8. Clinical Presentation of RSV related Croup • Rhinorrhea • Sore throat • Low grade fever • Seal like barking cough • Inspiratory stridor (severe cases)

9. Diagnosis of Bronchiolitis and Croup • Bronchiolitis • CXR • Clinical findings • Nasal wash for RSV antigen • Croup • Xray of soft tissues in neck • Clincal findings • Nasal wash for RSV antigen

10. Treatment of RSV Bronchiolitis • Prophylactic treatment with Synagis for high risk infants under 2 • Determined by severity of illness • Supportive Care • Hospital admission if severe • O2 if needed • Adequate hydration • Bronchodilators • No consistent significant benefit • Widely used on empiric basis

11. Treatment of RSV related Croup • Demonstrable benefit by 6 hours after single dose of either dexamethasone OR nebulized Pulmicort for moderate to severe croup • Nebulized Epi for significant respiratory distress • Mist?? • Studies neither support or refute its benefit

12. Prognosis of RSV • Most children make a full recovery in 1-2 weeks • Can be fatal for some infants (rare), especially if • Premature • chronic lung disease • certain heart diseases • Immunodeficiency • Increased risk for Asthma???

13. References Centers for Disease Control (2010). RSV. Retrieved March 15, 2010 from www.cdc.gov/rsv/index.html Medline Plus (2010). RSV. Retrieved March 15, 2010 from www.nlm.nig.gov/medlineplus/ency/article/001564.htm McCance, K.L. & Huether, S.E. (2006). Pathophysiology: The biologic basis for disease in adults and children. St. Louis: Elsevier Mosby.