A 21-Year-Old Woman With Dysuria and Vaginal Discharge

Melanie Malloy, MD, PhD; Richard H. Sinert, DO

Disclosures

August 21, 2017

Discussion

The diagnosis of cystitis in this case relies on a combination of history, physical examination findings, and laboratory findings. In young female patients with dysuria, four symptoms significantly increase the probability of UTI: dysuria, frequency, hematuria, and back pain. Flank pain, abdominal pain, and fever have not been found to be predictive of UTI.

The typical presentation of UTI includes a range of symptoms, including dysuria, urgency, frequency, back pain, abdominal pain, fever, hematuria, and costovertebral angle tenderness. Vaginal irritation or discharge makes the diagnosis less likely; however, these symptoms do not entirely rule out UTI as a diagnosis.

Some women present with asymptomatic bacteriuria, and UTI is discovered only by happenstance. A common example of this occurs in pregnancy, during which urinalysis may incidentally reveal bacteriuria. Treatment of asymptomatic bacteria is generally unnecessary except in the case of pregnancy, because in nonpregnant adults no clinical benefit has been found.[1] Pregnant women with such bacteria may be treated due to an increased risk of UTI and because UTI in pregnancy is more likely to be complicated by pyelonephritis.

The incidence of UTI in young, sexually active women is 0.5-0.7 cases per person-year, with an increase in relative risk with recent sexual intercourse, history of recurrent infection, and recent use of a diaphragm with spermicide.[2] Contrary to popular opinion, no increased risk is associated with delayed postcoital voiding. In one study, the incidence was highest in adults who were aged 23-30 years, never married, and white and had a history of more than two previous UTIs.[2]

No single historical or physical examination finding can reliably predict UTI in a symptomatic woman. However, certain findings in combination can effectively diagnose the condition. In a patient presenting with at least one symptom of UTI but also with vaginal discharge, a urine assay is recommended to confirm the diagnosis.

The patient in this case has vaginal discharge, which has been found to have a positive likelihood ratio of 0.4; this decreases the post-test probability of UTI to approximately 30%. A test/treatment algorithm has been developed that takes into account the improvement of some UTIs without treatment, the benefit of treating infected people, and the risk of treating uninfected people.[3] Using this algorithm, at this range (post-test probability of 1.5%-33%), further testing is warranted to avoid the risk for treatment of an uninfected patient and the risk of letting an infected patient go untreated. In a patient with UTI symptoms, equivocal urinalysis, and vaginal discharge, urine assay and testing for Neisseria gonorrhoeae (GC)/chlamydia are appropriate steps to pursue before treatment.

A pelvic examination without cervical motion tenderness or adnexal mass or tenderness, even in the presence of cervical discharge, made the alternative diagnosis of PID less likely. The increase in vaginal discharge in this case was probably not due to an infectious source, but rather to the action of the patient's oral contraceptive pills.

The absence of fever and other systemic symptoms, such as nausea and vomiting, led the diagnosis away from pyelonephritis, and the lack of flank pain and predisposing factors made nephrolithiasis less likely, even in the face of hematuria. With a moderate post-test probability, clinical judgment dictates whether to treat the patient or wait for the results of the urine assay.

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