Core IM: Mind the Gap on UTI’s and Delirium

September 12, 2018

Join us in this episode as we question everything you ever thought you knew about… urinary tract infections (UTI) and delirium. || By Steven R. Liu MD, Charlie Madeira MD and Dr. Janine Knudsen MD || Graphic Design by Ramon Thompson

Time Stamps:

  1. The basics – what are the official (IDSA) definitions for bacteriuria, pyuria, and UTI? (02:07)
  2. The lay of the land – how common are bacteriuria and delirium? (07:09)
  3. The big money question – do UTIs really cause delirium and what does the evidence tell us? (10:50)
  4. Review of teaching points (15:59)

Thank you to infectious disease attendings from NYU and Bellevue Hospitals, Dr. Ellie Carmody and Dr. Tania Kupferman, for peer reviewing this podcast!

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Show Notes:

  1. Definitions:
    • Asymptomatic bacteriuria is defined as more than 100,000 colony forming units of a bacteria growing in a urine culture, in a patient without symptoms. (IDSA)
    • Sterile pyuria is defined as 5-10 white blood cells per high powered field in a urine sample, without bacteria present.
    • A urinary tract infection (UTI), specifically uncomplicated cystitis, is a clinical diagnosis. Any patient with UTI symptoms such as dysuria, polyuria, or lower abdominal pain who has any bacteria growing in their urine culture – even as low as 100 colony forming units – can have a UTI.
    • Patients can have asymptomatic bacteriuria AND pyuria at the same time. They still need symptoms to have a diagnosis of UTI.
  2. Clinicians should treat patients with a UTI, but only in rare instances should they treat patients with asymptomatic bacteriuria. These include pregnant patients or patients awaiting a urologic procedure.
  3. Leukocyte esterase and nitrites on urinalysis have around 70-80% sensitivity and specificity for UTI.
  4. Bacteriuria is very common in the elderly, nearing 20% prevalence in some studies.
  5. Delirium is also very common in the elderly (up to 50% in certain hospitalized non-critically ill patients) and has many other causes besides infection such as medications, electrolyte abnormalities, and heart failure.
  6. On the surface, studies seem to show that delirium can be associated with UTIs. However most studies failed to adjust for confounders, were plagued by confirmation bias, and relied on poor data sources like billing codes.
  7. Other studies showed that treating delirious patients for their bacteriuria didn’t lead to better outcomes in a statistically significant way.  


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