Uncomplicated Urinary Tract Infection in Older Adults: Diagnosis and Treatment (Part 1)
It seems like a simple enough question: How do you diagnose and treat uncomplicated UTIs in older adults? The answer is: It depends. Part 1 of this post will discuss diagnosis of UTIs in this population, and part 2 will address treatment.
UTIs are the most common bacterial infection diagnosed in older adults (age 65 and over)1 and the most common reason for antibiotic use in this population.2 They account for 5% of ED visits by older adults.2
Bacteria in the urine occur on a spectrum from asymptomatic bacteriuria (ASB), uncomplicated UTI, to complicated UTI. It is important to distinguish between these three entities in order to guide therapy and prevent inappropriate antibiotic use.
1. Asymptomatic Bacteriuria (ASB)
This is defined as more than 100,000 cfu/mL of urine in 2 consecutive urine samples in women, or 1 sample in men in the absence of any symptoms that would suggest a UTI (we’ll come back to this). ASB is enormously prevalent, with rates in community-dwelling older adults around 5% for men and 6-10% for women. For institutionalized adults, the rates are as high as 15-35% for men and 25-50% for women.2 Pyuria with or without bacteriuria is also common in asymptomatic older adults, particularly those with chronic incontinence. Distinguishing ASB from UTIs is important to prevent unnecessary antibiotic use.
2. Uncomplicated UTIs
These are defined as the presence of genitourinary symptoms with pyuria (>10 WBC/mm/HPF) and bacteriuria (>100,000 cfu for a clean catch urine or >100 cfu for an in-and-out catheter specimen).2 In a cognitively normal older adult, this definition should work well most of the time. Typical symptoms include dysuria, suprapubic discomfort, urinary frequency, and urgency. However, the diagnostic challenge arises in older adults who have underlying cognitive impairment who may not have these typical symptoms, or may not be able to communicate it. In these patients, additional symptoms can be considered.
One diagnostic algorithm that has been proposed2 suggests obtaining a urine dipstick if the patient has:
- Fever OR
AND one of the following (or two of the following alone):
- CVA tenderness
- New or increased suprapubic tenderness
- Gross hematuria
- New or increased incontinence
- New or increased urgency
- New or increased frequency
- Change in character of the urine with a change in mental status
For men they also recommended checking a urine dipstick for:
- Pain, swelling, or tenderness of the testes, epididymis, or prostate, OR
- Acute dysuria AND one of the following:
- A change in the appearance or smell of the urine
- Mental status change
If the dipstick is positive for nitrites or leukocyte esterase in both women and men, the authors recommended obtaining a UA and culture, with treatment if there was pyuria and a positive culture. However, older men with a UTI are considered to have a complicated UTI.
In the ED, however, we have to decide empirically whether to treat, without the benefit of culture results. However, we can use this symptom list to help guide our medical decision making. If older adult patients present with the symptoms listed above, and if their UA is positive for bacteria and pyuria, consider treating even without classic genitourinary symptoms. If they have none of the symptoms listed above, and have only bacteriuria, it is more likely ASB, and may not require treatment.
- Bacteriuria + pyuria + symptoms = UTI = antibiotics
- Bacteriuria + no symptoms= ASB = no antibiotics
3. Complicated UTIs
Complicated UTIs include patients who have indwelling catheters, structural or functional genitourinary abnormalities, signs or symptoms of upper urinary tract infection (pyelonephritis), and those with signs of severe infection or sepsis. Also, all older adult men with UTIs are considered complicated. This has to do with prostatic enlargement, that can cause urinary retention. Without any of these features, well-appearing patients with bacteriuria have either uncomplicated UTIs or asymptomatic bacteriuria.
- UTIs and ASB are common in older adults, particularly those in long-term care facilities.
- ASB does not require treatment.
- To diagnose a UTI the patient should have pyuria, bacteriuria, and some symptoms. In cognitively intact older adults, symptoms are usually GU-related, such as dysuria, frequency, pelvic discomfort, incontinence, and change in the urine. In older adults with cognitive impairment, also consider non-specific symptoms such as altered mental status, functional decline, anorexia, and behavioral changes.
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