Urinary tract infections (UTIs) include cystitis (infection of the bladder) and pyelonephritis (infection of the kidney). Most episodes of cystitis and pyelonephritis are generally considered to be uncomplicated in otherwise healthy nonpregnant adults. A complicated urinary tract infection, whether localized to the lower or upper tract, is associated with an underlying condition that increases the risk of failing therapy.
Issues related to acute complicated cystitis and pyelonephritis will be reviewed here. Issues related to acute uncomplicated cystitis and pyelonephritis in women are discussed separately, as are issues related to UTIs in pregnant women, in men, and in the setting of indwelling urethral catheters. (See "Urinary tract infections and asymptomatic bacteriuria in pregnancy" and "Acute uncomplicated cystitis, pyelonephritis, and asymptomatic bacteriuria in men" and "Urinary tract infection associated with urethral catheters" and "Acute uncomplicated cystitis and pyelonephritis in women".)
A complicated urinary tract infection, whether localized to the lower or upper tract, is associated with an underlying condition that increases the risk of failing therapy, including the following:
- Symptoms for seven or more days before seeking care
- Hospital acquired infection
- Renal failure
- Urinary tract obstruction
- Presence of an indwelling urethral catheter, stent, nephrostomy tube or urinary diversion
- Recent urinary tract instrumentation
- Functional or anatomic abnormality of the urinary tract
- History of urinary tract infection in childhood
- Renal transplantation
Infection with a uropathogen with broad-spectrum antimicrobial resistance is also considered complicated although there are no data to suggest that such infections are more likely to fail if an antimicrobial to which the infecting pathogen is susceptible is used.