Join us in this episode as we question everything you ever thought you knew about… urinary tract infections (UTI) and delirium. 

Time Stamps

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

Show Notes

• 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.
• 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.
• Leukocyte esterase and nitrites on urinalysis have around 70-80% sensitivity and specificity for UTI.
• Bacteriuria is very common in the elderly, nearing 20% prevalence in some studies.
• 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.
• 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.
• Other studies showed that treating delirious patients for their bacteriuria didn’t lead to better outcomes in a statistically significant way.  

References

• Lindsay E. Nicolle, Suzanne Bradley, Richard Colgan, James C. Rice, Anthony Schaeffer, Thomas M. Hooton. IDSA Guidelines for the Diagnosis and Treatment of Asymptomatic Bacteriuria in Adults. Clinical Infectious Diseases, Volume 40, Issue 5, 1 March 2005.
• Kalpana Gupta, Thomas M. Hooton, Kurt G. Naber, Björn Wullt, Richard Colgan, Loren G. Miller, Gregory J. Moran, Lindsay E. Nicolle, Raul Raz, Anthony J. Schaeffer, David E. Soper. IDSA Guidelines for the Treatment of Acute Uncomplicated Cystitis and Pyelonephritis in Women: A 2010 Update. Clinical Infectious Diseases, Volume 52, Issue 5, 1 March 2011.
• St John A, Boyd JC, Lowes AJ, Price CP. “The Use of urinary dipstick tests to exclude urinary tract infection: a systematic review of the literature.” Am J Clin Pathol. 2006 Sep; 126(3):428-36.
• Hooton T, Gupta K, et al. Acute simple cystitis in women. UpToDate. Waltham, MA: UpToDate Inc. http://www.uptodate.com (Accessed on August 30, 2018)
• Nicolle LE “Asymptomatic bacteriuria: when to screen and when to treat.”  Infect Dis Clin N Am 17 2003 (367-394).
• Nicolle LE. Asymptomatic bacteriuria in the elderly. Infect Dis Clin North Am , 1997, vol. 11 (pg. 647-62).
• Inoye SJ. “Delirium in Older Persons.” N Engl J Med. 2006 Mar 16. 354:11
• Sakaguchi T, Watanabe M, Kawasaki C, et al. “AA novel scoring system to predict delirium and its relationship with the clinical course in patients with acute decompensated heart failure.” J Cardiol. 2018 Jun;71(6):564-569.
• Riquelme R, Torres A, el-Ebiary M, et al. “Community-acquired Pneumonia in the Elderly Clinical and Nutritional Aspects” Am J Respir Crit Care Med. 1997 Dec;156(6):1908-14.
• Pieralli F, Vannucchi V, Mancini A. “Delirium is a predictor of in-hospital mortality in elderly patients with community acquired pneumonia.” Intern Emerg MEd. 2014 Mar;9(2):195-200.
• Balogun SA, Philbrick JT. “Delirium, a Symptom of UTI in the Elderly: Fact or Fable? A Systematic Review.” Can Geriatr J 2013 Mar 5;17(1):22-6.
• Erickson et al. “Prevalence and factors associated with urinary tract infections in very old women” Arch Gerontol Geriatr. 2010.
• Levkoff SE, Evans DA, Liptzin B, et al. “Delirium: the occurrence and persistence of symptoms among elderly hospitalized patients.” Arch Intern Med. 1992 Feb 152.
• Rudberg MA, Pompei P, Foreman MD, Ross RE, Cassel CK. The natural history of delirium in older hospitalized patients: a syndrome of heterogeneity. Age Ageing. 1997;26:169-174.
• Dasgupta M, Brymer C, Elsayed S. Treatment of asymptomatic UTI in older delirious medical in-patients: A prospective cohort study. Arch Gerontol Geriatr. 2017;72:127.
• Uthamalingham S, Gurm GS, Daley M, et al. Usefulness of acute delirium as a predictor of adverse outcomes in patients >65 years of age with acute decompensated heart failure. Am J Cardiol 2011;108:402–8.
• Kennedy M, Enander RA, Tadiri SP, Wolfe RE, Shapiro NI, Marcantonio ER. Delirium risk prediction, healthcare use and mortality of elderly adults in the emergency department. J Am Geriatr Soc 2014;62:462-469