Urinary Tract Infection (UTI) and Cystitis (Bladder Infection) in Females Differential Diagnoses

Updated: Aug 27, 2019
  • Author: John L Brusch, MD, FACP; Chief Editor: Michael Stuart Bronze, MD  more...
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DDx

Diagnostic Considerations

Occult pyelonephritis occurs in 15-50% (or more) of all urinary tract infections (UTIs), based on several studies on localization of organisms within the urinary tract. This usually occurs in older women. It appears that these patients are unable to mount a fever or develop an elevated white count or costovertebral angle (CVA) tenderness. These patients may present with an unexplained fall or a change in mental status.

Postmenopausal women may also experience senile urethritis. In addition to urinary burning, frequency, and urgency, these patients may complain of vaginal and vulvar itching and discharge. Physical examination reveals a dry, pale vaginal epithelium and eversion of the urethral mucosa. Senile urethritis responds to topical estrogen therapy.

The differential diagnosis for infectious causes of sterile pyuria includes perinephric abscess, urethral syndrome, renal tuberculosis, and fungal infections of the urinary tract system. Noninfectious causes of pyuria include the following:

  • Uric acid and hypercalcemic nephropathy

  • Lithium and heavy metal toxicity

  • Sarcoidosis and other granulomatous diseases (eg, tuberculosis)

  • Interstitial cystitis

  • Polycystic kidney disease

  • Genitourinary malignancy

  • Renal transplant rejection

  • Any periurethral process

Consider UTI in any condition involving pain the flank and back or pain in the abdomen and pelvis. Also consider cervicitis and Chlamydia infection. Do not assume that a sexually active female with dysuria has a UTI without first excluding the possibility of sexually transmitted disease–related cervicitis, vaginitis, or pelvic inflammatory disease.

UTIs in pregnancy have potentially adverse outcomes for both the mother and the fetus. Obtain a urine culture in all pregnant patients with suspected UTI, as the results may provide the physician or the follow-up physician with valuable information if the patient does not respond as expected to treatment. Pyuria and bacteriuria are always treated during pregnancy, regardless of whether symptoms are present.

Patients with diabetes mellitus are at increased risk for complicated UTIs. Diagnostic considerations include the following:

  • Renal and perirenal abscess

  • Emphysematous pyelonephritis

  • Emphysematous cystitis

  • Fungal infections

  • Xanthogranulomatous pyelonephritis

  • Papillary necrosis

Older patients who appear toxic are more likely to have obstruction complicating their UTI. Obtain a structural study to rule out this possibility.

Differential Diagnoses