6 UTI Myths - From EMedHome

A 2014 CDC report noted that “UTI” treatment was avoidable at least 39% of the time (1). A just-published article reviews common myths regarding UTI (2). Given that Emergency Medicine providers make the diagnosis of UTI on a daily basis, this week’s Clinical Pearl is a synopsis of these UTI myths:

Myth: The Urine Is Cloudy and Smells Bad so The Patient Has a UTI.  Visual inspection of urine clarity is not helpful in diagnosing UTI in women (2). Foul-smelling urine is an unreliable indicator of infection in catheterized patients, and is usually dependent on patients' hydration status and concentration of urea in the urine (2,3).

Myth: The Urine Has Bacteria Present so The Patient Has a UTI.  The presence of bacteria in the urine on microscopic examination or by positive culture without UTI symptoms is NOT an indication of a UTI due to the possibility of contamination and asymptomatic bacteriuria. Asymptomatic bacteriuria is common in all age groups and is frequently over-treated. Recent evidence suggests that in younger women with true recurrent UTI, bacteriuria may be “protective” for future UTI with more pathogenic organisms (4). Virtually 100% of patients with an indwelling Foley catheter are colonized within 2 weeks of placement with 2–5 organisms (2).

Myth: Pyuria defines UTI. In leukopenic patients, the WBC count may be artificially low. Borderline WBC counts of 6–10 cells/mL may reflect the patient's state of hydration. Noninfectious conditions (e.g. acute renal failure, STD, or nonifectious cystitis from a catheter) may result in pyuria.

Myth: The Urine Has Nitrates Present so The Patient Has a UTI. Urine nitrates should not be used alone to start antibiotics. Urine nitrate has a high true-positive rate for bacteriuria, but bacteriuria, as noted above, does not define a clinically significant UTI. In a study of elderly nursing home residents, even if both leukocyte esterase AND nitrite analyses were positive, the sensitivity for UTI was only 48%, indicating the need to correlate with clinical symptoms that suggest a UTI (5).

Myth: Falls and Acute Mental Status Changes in the Elderly Are Usually Caused by UTI. Attribution of altered mental status to bacteriuria can result in failure to identify the true cause (2). Elderly patients with acute mental status changes accompanied by bacteriuria and pyuria, without clinical instability or other signs or symptoms of UTI, can reasonably be observed for resolution of confusion for 24-48 hrs without antibiotics, while searching for other causes of confusion (2).

Myth: The Presence of Yeast or Candida in the Urine, Especially in Patients with Indwelling Catheters, Needs to Be Treated. The occurrence of candiduria in the catheterized patient is common, and most often reflects colonization or asymptomatic infection (2,6). Treatment of candida in the urine should occur only in rare situations, such as clear signs and symptoms of infection and no alternative source of infection. Isolation of candida in the urine of noncatheterized patients should raise concerns about vaginal or external contamination.

References:
(1) Fridkin S, et al. MMWR Morb Mortal Wkly Rep. 2014; 63: 194–200.
(2) Schulz L, et al. Journal of Emerg Med, April 7 2016. [Epub]
(3) Nicolle LE, et al. Clin Infect Dis. 2005; 40: 643–654.
(4) Cai T, et al. Clin Infect Dis. 2012; 55: 771–777.
(5) Sundvall PD, et al. BMC Geriatr. 2009; 9: 32.
(6) Kauffman CA, et al. Clin Infect Dis. 2000; 30: 14–18.