A 59 year-old woman with recently-diagnosed right frontal WHO grade III astrocytoma s/p subtotal resection presents to the ED with worsening left hemiparesis and is found to have worsening perilesional enhancement and edema on non-contrast head CT. In the ED, while awaiting an MRI, she undergoes a broad workup, including CBC, CMP, UA, and chest X-ray. Labs are notable for WBC 6.8, Hb 10.3, Plt 217, Na 139, K 4, Cl 110, HCO3 24, BUN 8, Cr 0.69, glucose 147. UA demonstrates pH 6.5, WBC 80, leuk esterase positive, nitrite negative, protein negative. The nurse who collected the urine said it was malodorous.
On exam, she is alert and oriented. Language is intact. Mild flattening of the left nasolabial fold. No dysarthria. LUE and LLE strength is 3/5 (had been 4/5 in the past month).
Unlikely! Any time we have patients with neurologic deficits that are worse than baseline, we always want to find an easy answer for what could've triggered the decline. Infection is an easy answer. However, the evidence presented here doesn't actually support a UTI. We already see a clear structural reason for why she's had worsening hemiparesis. Even setting that aside, however, her UA simply shows an elevated WBC with positive leuk esterase. The latter just indicates that leukocytes are present in the urine. Many would colloquially call this a "positive UA." What really matters is whether the patient has urinary symptoms (i.e. frequency, urgency, dysuria, suprapubic pain). In a consensus group paper, Nelson et al. found that the diagnostic value of UA for diagnosting UTI is limited. (The positive predictive value for positive leuk esterase ranged from 43-56%, whereas that of positive nitrite ranged from 50-83%.) Specifically, they note that "while the absence of pyuria can help rule out infection in most patient populations, the positive predictive value of pyuria for diagnosing infection is exceedingly low as it often indicates the presence of genitourinary inflammation due to many other possible noninfectious reasons." Urine odor is also commonly cited as a marker of UTI, though this isn't strictly true. Additionally, a review of patients in an incontinent long-term care population found that urine odor is not an accurate predictor of UTI.
By definition, the patient just has pyuria at this point. If she develops urinary symptoms, then we can reevaluate, as that would suggest UTI. In the absence of symptoms, if the urine culture runs and reveals some growth, that would just represent asymptomatic bactiuria, and should not be treated unless symptoms develop.
Copyright © 2024-2025 Andrew M. Nguyen, M.D. For educational use only.
This work is licensed under
CC BY-NC-SA 4.0.
