Episode 94 UTI Myths and Misconceptions

This is EM Cases Episode 94 - UTI Myths and Misconceptions In 2014, the CDC reported that UTI antibiotic treatment was avoidable at least 39% of the time. Why? Over-diagnosis and treatment results from the fact that asymptomatic bacteriuria is very common in all age groups, urine cultures are frequently ordered without an appropriate indication, and urinalysis results are often misinterpreted. Although we still appropriately manage most patients with UTI, we need to learn about some subtleties of clinical diagnosis, urine test interpretation and antibiotic choice to improve our management of UTI. So with these goals in mind, EM Cases' Dr. Justin Morgenstern (@First10EM) and Dr. Andrew Morris (@ASPphysician), an infectious disease specialist and medical director of the antimicrobial stewardship program at Sinai Health System and University Health Network in Toronto, will help fine-tune your approach to the diagnosis and management of UTI as well as dispel some common UTI myths and misconceptions. Think of the last time you prescribed antibiotics to a patient for suspected UTI – what convinced you that they had a UTI? Was it their story? Their exam? Or was it the urine dip results the nurse handed to you before you saw them? Does a patient’s indwelling catheter distort the urinalysis? How many WBCs/hpf is enough WBCs to call it a UTI? Can culture results be trusted if there are epithelial cells in the specimen? Can a “dirty” urine in an obtunded elderly patient help guide management?... Podcast production, editing and sound design by Anton Helman. Written summary and blog post by Shaun Mehta, Alex Hart, Lorraine Lau and Anton Helman, edited by Anton Helman.  Cite this podcast as: Helman, A, Morgenstern, J, Morris, A. UTI Myths and Misconceptions. Emergency Medicine Cases. https://emergencymedicinecases.com/uti-myths-misconceptions/. Accessed [date]. History taking in patients who present with suspected UTI While there is no single clinical symptom, sign or lab test that is accurate enough to rule in or rule out a UTI, certain symptoms in combination greatly increase the likelihood of a UTI. Even though only about half of patients who present with dysuria and frequency have a UTI, if you add the absence of symptoms suggesting vaginitis or cervicitis (vaginal irritation, bleeding, and discharge) the likelihood increases to over 90% with a +LR =24.6. Other helpful historical features include a self diagnosed UTI which has a +LR = 4 and urine cloudy appearance which has a specificity of 96% for UTI. Which patients with a clinical presentation consistent with a lower UTI require a work-up for UTI? Urine tests are not required for the majority of patients with suspected lower UTI (cystitis) as it is a clinical diagnosis and the urine tests can be misleading. Urinalysis is most useful for intermediate-risk patients. Urine tests are not necessary for low-risk patients (they probably don’t have a UTI), nor for the patient with a convincing clinical presentation (you will treat regardless). Indications for urine tests for suspected lower UTI include: * Immunocompromised patients * History of multiple courses of antimicrobial therapy * History of antibiotic resistance * History of multiple drug allergies Pearl: UTI is a clinical diagnosis, not a laboratory one. Microscopy vs dipstick in UTI myths and misconceptions Microscopy is slightly more accurate than dipstick, but remember to put the results into context of the clinical picture. So the dipstick shows… * Pyuria OR nitrites - sensitivity up to 94%, but poor specificity * Pyuria AND nitrites - specificity ~100%,