Editing Urinary Tract Infections (section)

==== Emphysematous pyelonephritis ====
* '''An acute necrotizing parenchymal and peri-renal infection caused by gas-forming uropathogens'''
* '''Pathogens'''
** '''E. coli is the most common cause of emphysematous pyelonephritis and emphysematous cystitis'''
* '''Usually occurs in diabetic patients'''
* '''Diagnosis and Evaluation'''
** '''Almost all patients display the classic triad of fever, vomiting, and flank pain'''
** '''Imaging'''
*** '''The diagnosis is established radiographically by the presence of gas in the parenchyma or collecting system.'''
**** '''A crescentic collection of gas over the upper pole of the kidney is more distinctive.'''
**** As the infection progresses, gas extends to the perinephric space and retroperitoneum.
**** '''This distribution of gas should not be confused with cases of emphysematous pyelitis in which air is in the collecting system of the kidney. Emphysematous pyelitis is secondary to a gas-forming bacterial UTI, often occurs in non-diabetic patients, is less serious, and usually responds to antimicrobial therapy.'''
* '''Management'''
** '''Requires urgent management'''.
*** '''Most patients are septic, and fluid resuscitation and broad-spectrum antimicrobial therapy are essential.'''
** '''If a kidney is obstructed, urinary diversion (stent or nephrostomy) must be instituted'''
** '''If the kidney is functioning, medical therapy can be considered.'''
** '''Indications for nephrectomy (2):'''
**# '''Affected kidney is non-functioning and not obstructed''' because medical treatment alone is usually lethal
**# '''Failure to improve after a few days of therapy'''