Assessment
A preliminary diagnosis of acute female cystitis (AFC) is made by assessing patient risk factors, signs and symptoms. A combination of the classic words, “I have this pain when I urinate (dysuria), urgency, burning or frequency that just started,” describes the symptoms of acute cystitis. The urgent need to urinate may allow only a few drops of urine to pass before the burning sensation occurs and the need to urinate begins again. The urine may be cloudy, bloody, or foul-smelling. Infrequently there may be a mild fever or pain in the lower back or groin area.
Dysuria
Dysuria is associated with bacterial cystitis, STDs (sexually transmitted diseases), or vaginitis. A differentiation needs to be made between location, risk factors and cause of the dysuria before treatment can be initiated. Internal dysuria is associated with urinary tract infections or STDs, while external dysuria is associated with vaginitis. Pyuria and hematuria are absent in vaginitis. Patients with vaginitis usually complain of vaginal discharge, odor, itching or burning around the vaginolabial area. Cervical cultures for N. gonorrhoeae and C. trachomatis are indicated, if the diagnosis is in question.See TABLE 4 for clinical differentiation of major causes of dysuria.
| TABLE 4: Clinical Differentiation of Major Causes of Dysuria | |||
| Clinical Features | UTI | STD | Vaginitis |
| Internal dysuria | X | X | |
| External dysuria | X | ||
| Frequency, urgency, voiding small volumes | X | ||
| Occasional history of frequency, urgency, or voiding small volumes | X | ||
| Abrupt onset | X | ||
| Gradual onset | X | X | |
| Suprapubic pain | X | ||
| Often associated with spermicide and/or diaphragm use | X | ||
| Painful intercourse | X | ||
| Presence of pyuria | X | X | |
| Presence of hematuria | X | ||
| History of new or multiple sex partners | X | X | X |
| Vaginal discharge | X | X | |
| Vaginal odor | X | ||
| Pruritus | X | ||
Urine Culture / Testing
Urine culture and susceptibility testing add little to the choice of an empiric antibiotic for treatment, because of the limited spectrum and number of acute female cystitis pathogens. Susceptibility is usually predictable, but regional variations in resistance patterns do occur. Many patients, therefore, may receive an abbreviated laboratory work-up using dipstick tests to screen for the presence of bacteria or pyuria. When combined, the two tests have a sensitivity of 70%–100% and a specificity of 60%–90%.
The leukocyte esterase (LE) dipstick test is used to screen for pyuria (presence of pus in the urine when voided). LE, an enzyme found in neutrophil granules, reacts with an impregnated reagent pad to produce a blue color within 2–5 minutes. A positive test indicates the presence of white blood cells (WBC). When compared to standard methods of defining UTIs (isolating >=10 CFU/mL of pathogenic bacteria) or significant pyuria (>=10 WBC/mm urine) the sensitivity is 75%–96% and the specificity is 94%–98%. Pyuria indicates inflammation and not necessarily an infection. This is an efficient, cost-effective method for determining the presence of pyuria when routine microscopy is unavailable, impractical or for an outpatient evaluation.Vitamin C and phenazopyridine may cause false-negative or unreadable results.
The nitrate test is also widely available, for use at home or in the office. The nitrate test is qualitative in that it is used as a surrogate to detect Gram-negative bacteria, since only Gram-negative bacteria are able to produce nitrate. An aromatic amine-impregnated pad produces an azo color within 60 seconds if urinary nitrites are present. Urinary nitrites are produced by the action of Gram-negative bacteria (Enterobacteriaceae) metabolism on dietary nitrates through nitrate reductase. False-negatives can result from recent antibiotic therapy, low urinary pH (as occurs with high doses of ascorbic acid), lack of dietary nitrates, or when diuresis has created insufficient urinary nitrate levels. False-negatives also occur when Pseudomonas sp. or Gram-positive bacteria such as Staphylococcus sp., or Enterococcus sp., which lack nitrate reductase, are unable to produce nitrite. Sensitivity of the test ranges between 35%–85%, and the specificity ranges between 92%–100%.
In summary, the diagnosis may be based on objective data, subjective signs and symptoms, or both. Women with classic signs and symptoms are often empirically treated with antibiotics. Cultures need to be performed when the diagnosis is unclear; or there are other risk factors, including a history of recurrent infections; or more than the classic signs or symptoms are involved, including symptoms such as fever, lower back or flank pain, or signs associated with vaginitis.