Presentation
Left flank pain and a mild fever.
Patient Data
Calculus in the left renal pelvis.
The calyces are dilated with foci of gas within the collecting system and renal parenchyma.
Thinning of the left renal cortex. No peri-nephric collection.
Case Discussion
This is a case of emphysematous pyelonephritis. This constitutes only a small percentage of pyelonephritis, largely occurring in diabetic patients and others with an immunosuppressive state. E. coli is a the commonest responsible organism.
It is most commonly depicted on CT - the gas component being very difficult to observe on ultrasound, even though this modality is very frequently first performed.
Urolithiasis is very often observed in this group of patients, as in this case.