Answer:
Emphysematous Pyelonephritis

Discussion:
Types

• Type I (33%)
  • Streaky or mottled gas in interstitium of renal parenchyma radiating from medulla to cortex
  • Crescent of subcapsular or perinephric gas
  • No fluid collection (= no effective immune response)
  • Prognosis in this type is poor (69% mortality)
• Type II (66%)
  • Bubbly and/or loculated intrarenal gas (infers presence of abscess)
  • Renal and/or perirenal fluid collection
  • Gas within collecting system in almost all