History and exam

Key diagnostic factors

common

fever

Nonspecific evidence of systemic infection.

Patients on corticosteroids or anti-inflammatory agents, or who have advanced renal failure or sepsis syndrome, may have normal temperature.

Found in 77% of patients.[6]

Other diagnostic factors

common

nausea and vomiting

Nonspecific evidence of systemic infection. May be accompanied by dehydration and/or hypotension.

dysuria, frequency, or urgency

Usually associated with cystitis or urethritis.

Not necessarily diagnostic of upper tract infection but may be concomitant.[6]

flank pain or costovertebral angle tenderness

Usually unilateral, may or may not be present, and is often lacking in early or mild disease.

In 86%, flank pain or costovertebral angle tenderness is present.[6]

Risk factors

strong

urinary tract infection

Risk factor for acute uncomplicated case.

If female and occurs in the previous 12 months, an increased risk of developing symptoms (odds ratio of 4.4).[6]

Previous urinary tract infection may predispose to a subsequent urinary tract infection through behavioral, microbiological, or genetic factors.[6]

If occurs in the previous 30 days, associated with an increased disease risk (odds ratio of 12.5).[6]

diabetes mellitus

Medication-treated diabetes is reported as a risk factor for urinary tract infection in postmenopausal women.[25][26]

Increased prevalence of asymptomatic vaginal E coli colonization among postmenopausal women with diabetes who are receiving insulin treatment.[27]

Greater adherence of uropathogenic E coli to uroepithelial cells may be related to impaired cytokine secretion and reduced polymorphonuclear inflammatory response.[28]

stress incontinence

Risk factor for uncomplicated disease, associated with an odds ratio of 3.9.[6]

foreign body in urinary tract (e.g., calculus, catheter)

Risk factor for complicated cases.

Renal stones allow bacteria to remain hidden in the interior of the stone, whereas indwelling catheters may allow bacteria to form a biofilm, which helps resist antibiotic treatment.

anatomic/functional urinary abnormality

Risk factor for complicated disease.

Such abnormalities include polycystic kidney disease, enlarged prostate, vesicoureteric reflux, ureteroceles, and neurogenic bladder.

Anatomic problems such as renal cysts and ureteroceles allow bacteria to remain in hard-to-access locations in the body (e.g., inside cysts).

Functional abnormalities such as neurogenic bladder and reflux increase the likelihood that the kidneys will be exposed to bacteria.

immunosuppressive state (e.g., HIV, transplantation, chemotherapy, corticosteroid use)

Risk factor for complicated cases.

Immunosuppression can occur to varying degrees, which will determine the kinds of infections that are more likely and the degree of risk associated with these infections.

Corticosteroids suppress the entire cytokine and inflammatory cascade, making infections with all agents more likely, whereas only a slight decrease in CD4 count with HIV may not increase infection risk.

pregnancy

Risk factor for complicated disease.

The enlarging uterus compressing the ureters and the increasing laxity of the pelvic support system with the hormonal changes promote the likelihood of obstructive uropathy. An increased residual volume of urine in the bladder and urinary stasis results in vesicoureteral reflux which increases the risk of bacterial colonization and ascending infection of the urinary tract during pregnancy.​[10]

frequent sexual intercourse

Risk factor for uncomplicated disease.

Women reporting a frequency of sexual intercourse ≥3 times per week in the previous 30 days were more likely to develop disease (odds ratio of 5.6).[6] An odds ratio of 1 implies that the event is equally likely in both groups. An odds ratio >1 implies that the event is more likely in the first group. An odds ratio <1 implies that the event is less likely in the first group. The mechanical action of sexual intercourse may facilitate entry to Escherichia coli strains into the bladder.[29]

weak

mother with urinary tract infection history

Risk factor for uncomplicated disease (odds ratio 1.6).[6]

Suggests a role for genetic or long-term environmental exposures.[30]

new sex partner

Risk factor for uncomplicated disease, associated with an odds ratio of 2.2.[6]

spermicide use

Associated with an odds ratio of 1.7.[6]

May alter the normal lactobacillus-dominant vaginal flora and facilitate E coli colonization of the vagina.[31]

age between 18 and 50 years

Uncomplicated disease is diagnosed most often in adult women between these ages.[7]

age >60 years

Risk factor for complicated disease.

The risk of other medical problems, such as diabetes and enlarged prostate, increases with age.

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