RSV

1
RSV

• Respiratory syncytial virus

2
RSV

• The major cause of bronchiolitis and pneumonia
  in children lt1 yr
• The most important respiratory tract pathogen of
  early childhood.

3
RSV

• RNA virus
• Develops in the cytoplasm of infected cells and
  matures by budding from the plasma membrane

4
RSV

• Placentally transmitted anti-RSV Ab has some
  protective effect --gt low frequency of severe
  infections in the first 4-6 wk

5
RSV

• Coryza, pharyngitis, occasionally otitis media
• 10-40 bronchitis, bronchopneumonia and
  bronchiolitis

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Bronchiolitis

• The most common clinical diagnosis in infants
  hospitalized with RSV infections

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Bronchiolitis

• Virus-induced necrosis of the bronchiolar
  epithelium
• Hypersecretion of mucus
• Inflammatory cell infiltration
• Edema of the surrounding submucosa

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Bronchiolitis

• --gt Formation of mucous plugs obstructing
  bronchioles
• --gt Hyperinflation or collapse of distal lung
  tissue
• (Older children and adults tolerate bronchiolar
  edema better than infants)

9
Clinical manifestations

• Rhinorrhea, pharyngitis
• (Sneezing, low grade fever)
• 1-3 days later cough, wheezing
• Auscultation diffuse rhonchi, fine crackles,
  wheezes
• CXR normal

10
Clinical manifestations

• Cough, wheezing increase
• Air hunger--gt increased respiratory rate,
  intercostal and subcostal retractions,
  hyperexpansion of the chest, restlessness,
  peripheral cyanosis

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Clinical manifestations

• Life-threatening illness central cyanosis,
  tachypneagt70, apneic spells
• Chest hyperexpanded
• Silent to auscultation
• CXR 10 normal, 50 air trapping, 50-80
  peribronchial thickening or interstitial pneumonia

12
Clinical manifestations

• After the critical period, improvement occurs
  rapidly
• Recovery is complete in a few days

13
Diagnosis

• Bronchiolitis a clinical dx--gt symptoms, age,
  household, outbreak
• Lab--gt
• WBC normal
• bacterial culture of the throat normal flora
• hypoxemia frequent (ventilation-perfusion
  mismatch)

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Diagnosis

• Bacterial or chlamydial involvement?
• Clinically mild
• CXR infiltrates are absent
• --gt little likelihood

15
Diagnosis

• Definite diagnosis of RSV infection detection of
  virus or viral Ag in respiratory secretions

16
Treatment

• Symptomatic
• Humidified oxygen
• Adequate hydration
• NG or iv feeding when sucking is difficult due to
  tachypnea
• Propped up at an angle of 10-30 degrees

17
Treatment

• Bronchodilators
• Ribavirin (antiviral drug) shortened hospital
  stay, reduced mortality?
• --gt high-risk infants cyanotic congenital heart
  dz, bronchopulmonary dysplasia, severe
  immunodeficiency

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Prognosis

• Good
• Mortality of hospitalized infants with RSV
  infection 2
• Premature infants
• Underlying dz neuromuscular, pulmonary,
  cardiovascular or immunologic system