Emphysematous pyelonephritis is a life threatening necrotising parenchymal and peri-renal infection caused by gas-forming urinary pathogens.
Usually occurring in diabetics – hypothesis that high glucose levels are the substrate for micro-organisms like E.coli to produce carbon dioxide via the fermentation of sugar
Risk factors:
- Diabetes
- Immunosuppression
- Renal obstruction and calculi
- Papillary necrosis
- Women > men 6:1
Clinical presentation:
Presents as severe pyelonephritis – fevers, vomiting and flank pain.
Pneumaturia occasionally present if involving the collecting system.
Urine cultures invariably positive – E.coli most common culprit, followed by Klebsiella.
(Rarely proteus, enterococcus, pseudomonas, clostridium or candida).
Imaging
Diagnosis is made on CT with gas in the parenchyma which can progress to involve the perinephric space and retroperitoneum.
Look for concurrent renal obstruction and stones.
Emphysematous pyelitis involves gas in the collecting system only (cf parenchyma) and is often much less severe and responds to medical management.
Management
Manage sepsis as per pyelonephritis with IV fluid resuscitation, IV antibiotics and early ICU involvement.
Obstruction needs to be managed with either a stent or nephrostomy.
Most modern cases can be managed with antibiotics, drainage (stent or nephrostomy) +/- percutaneous drainage.
Nephrectomy was traditionally used to manage but this can be avoided in most cases now.
Modern mortality may still be around 10 %.
Emphysematous cystitis is characterised by gas in the bladder wall and can usually be managed with catheter drainage and broad spectrum antibiotics.
Gas may also just be present in the lumen of the bladder (cf intramural gas) secondary to gas producing organisms. More common in diabetics.
Cystectomy has been reported to be necessary in extreme cases.