Pediatric Round Pneumonia

• Etiology: Streptococcus pneumoniae in 90%
• Imaging:
  — Due to absence or poor development of collateral airways due to immature lung anatomy
  — Inflammation spreads centrifugally giving round appearance
  — In superior segments of lower lobes
  — Solitary round opacity that is a mean of 3-4 centimeters in size
• Note: Collateral airways allow ventilation of alveoli through the channels bypassing the normal airway but are poorly developed in infants
• Note: Channels of Lambert and pores of Khan for intralobular collateral circulation, Pathway of Martin for interlobular circulation
• DDX: Pulmonary mass so must get CXR 1 month post treatment to document resolution of mass and document it is not a malignancy
• Complications:
• Treatment: Antibiotics
• Clinical: Seen in less than 8 years old and peaks at 3-5 years old

Radiology Cases of Round Pneumonia