Pediatric Viral Pneumonia

  • Etiology:
    — Respiratory syncytial virus infection leads to
    — Disease of airways and airway inflammation which leads to bronchial wall thickening which leads to ball-valve effect which leads to air trapping
    — Increased mucous production leads to mucous plugs
  • Imaging CXR:
    — Airway thickening
    — Hyperinflation = flattened diaphragm
    — Shifting subsegmental atelectasis from mucous plugs
  • Note: A normal CXR does not rule out viral pneumonia as CXR is insensitive to the detection of viral pneumonia
  • DDX: Asthma, congenital heart disease
  • Complications: Small percentage get concurrent bacterial pneumonioa superinfection
  • Treatment: Antivirals in some cases
  • Clinical:

Radiology Cases of Viral Pneumonia

CXR of respiratory syncytial virus pneumonia
CXR PA and lateral shows airway thickening and lung hyperexpansion with flattening of the hemidiaphragms.
CXR of viral pneumonia
CXR PA (left) and lateral (right) shows thickening of the airways centrally and hyperexpansion of the lungs bilaterally leading to flattening of the diaphragm.

Radiology Cases of Viral Pneumonia with Subsegmental Atelectasis

CXR of pediatric viral pneumonia with subsegmental atelectasis
CXR AP (left) and lateral (right) shows thickened central airways and bilateral lung hyperexpansion causing flattening of the diaphragm. There is an opacity in the medial aspect of the right middle lobe causing the right heart border to be obscured (silhouette sign).

Radiology Cases of Viral Pneumonia with Bacterial Suprainfection

CXR of adenovirus pneumonia with bacterial superinfection
Initial CXR PA (left) shows central airway thickening and bilateral lung hyperinflation resulting in flattening of the diaphragm. CXR PA obtained 3 days later (right) shows new dense opacities obscuring the left and right heart borders (silhouette sign).
CXR of viral pneumonia with a bacterial suprainfection
CXR shows diffuse airway thickening and hyperexpansion along with an infiltrate obscuring the right heart border and the medial hemidiaphragms bilaterally.

Radiology Cases of Viral Pneumonia Causing Thymus Involution and Thymus Rebound

CXR of thymus rebound
CXR AP (left) shows central airway thickening and lung hyperexpansion. The thymus is not visible. Repeat CXR AP obtained 3 months after resolution of respiratory symptoms (right) shows normal central airways and lung expansion. The thymus is now well visualized and is normal in appearance.