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Emphysematous Pyelonephritis

Created: 9/1/2006


Emphysematous Pyelonephritis



A life-threatening, fulminant, necrotising upper urinary tract infection associated with gas within the kidney and/or perinephric space

NB. Gas confined to the renal pelvis should be called emphysematous pyelitis



Male to female 1:2

Mean age 54 years

Mortality up to 80%

EPN is bilateral in 5-7% patients


Aetiological Risk Factors

Diabetes mellitus (up to 90%)

Obstructive uropathy

Urinary calculi

Calyceal stenosis



Signs and symptoms

Pyrexia, rigors, flank/loin pain, lethargy, and confusion not responding to treatment

PUO (18% of patients)

Septicaemic shock and abdominal symptoms are less common manifestations

Crepitant mass may be present

Bacteriuria, positive blood culture and leukocytosis are often present



Air in the renal collecting system


Renal enlargement with delayed or absent excretion


CT (examination of choice)

Intraparenchymal, intracalyceal, and intrapelvic gas and extension into perinephric space are readily identified on nonenhanced CT scans

Mottled areas of low attenuation extend radially along the pyramids

Pus may be seen extending into the renal veins


Differential diagnosis

Retroperitoneal perforation of an abdominal viscus

Psoas abscess secondary to gas-forming organisms

Reflux of air from the bladder

Bronchorenal, enterorenal, or cutaneorenal fistulae

Air in a focal renal abscess (not life threatening)



Most patients require immediate surgical intervention

Aggressive antibiotic therapy,

Drainage procedures to relieve obstruction

Prompt nephrectomy in life-threatening situations

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