Computed tomography of renal emergencies: A comprehensive diagnostic guide for radiology residents

Table 3 Imaging findings and management of infectious renal pathologies

Pathology	Imaging findings	Management
Pyelonephritis	Multifocal wedge-shaped hypoattenuation extending from the renal papilla to cortex. Round hypoattenuation rim-enhancing collections indicate abscess formation	Antibiotics and percutaneous or surgical abscess drainage
Emphysematous pyelonephritis	Gas locules within the renal collecting system with or without extension to the renal parenchyma, perinephric space, or pararenal space	Grade I, II: Antibiotics, percutaneous drainage of abscess, and decompression of urinary tract obstruction, if any. Grade III: Immediate nephrectomy and antibiotics. Grade IV: Same as grade I and II; nephrectomy if the initial treatment fails
Xanthogranulomatous pyelonephritis	Enlarged kidney with dilated renal calyces and a large staghorn calculus	Nephron-sparing nephrectomy in focal disease and total nephrectomy in diffuse involvement
Pyonephrosis	Complex fluid within the renal collecting system with or without internal septations	Urgent decompression with percutaneous or retrograde stent placement. Nephrectomy in advanced cases with irreversible renal damage