Introduction

Pyuria is defined as the presence of 10 or more white cells per cubic millimetre in a urine specimen, 3 or more white cells per high-power field of fresh urine, a positive result on Gram staining of a fresh urine specimen, or a urinary dipstick test that is positive for leukocyte esterase.

Pyuria prevalence in the elderly increases with age. A study on 245 urine samples from elderly patients in a long-term care facility showed that 88% of the samples had ≥10 white blood cell counts per millimetre square, thus defining pyuria. Another 80% of the samples were without significant bacteria in the urine, and still defined the presence of pyuria. This suggests that pyuria is widespread and can occur in the absence of urinary tract infections (UTIs).¹

An estimated 30-50% of people in long-term care facilities had positive urine cultures at any given time, which are almost always related to pyuria. This high prevalence affects both men and women, and it increases with functional disability.²

Interpreting it in the elderly can be challenging due to various factors that may confuse, including silent bacteriuria, age-related changes in the urinary tract and bladder, and common comorbidities.¹

Common conditions contributing to pyuria in older adults

The following conditions are contributors to pyuria in older adults, this includes:

Urinary tract infection(UTI)

The most prevalent cause of pyuria in older persons is urinary tract infection (UTI), which is also the most commonly treated bacterial infection in the elderly in hospitals.3 The incidence of urinary tract infections is predicted to be 140:1000 in women and 50:1000 in males over the age of 75.³ 

The incidence of urinary tract infection in older adults increases with age due to some factors such as the use of prolonged ureteral catheter, estrogen deficiency in postmenopausal women, incomplete bladder from conditions like benign prostatic hyperplasia, and comorbidities such as diabetes.⁴

Nonspecific symptoms are often present in the elderly, such as delirium, falls, generalised weakness, increased incontinence, and reduced mobility. Other classical symptoms of urinary tract infection are dysuria, urgency, or suprapubic discomfort, and they may be unreported due to cognitive impairment or communication gaps.⁵

Diagnosis of urinary tract infection in older adults can be confirmed by the following: 

• Presence of relevant clinical symptoms and 
• Positive urine culture showing significant bacteriuria.

While pyuria is common in infection, its presence alone is not sufficient for diagnosing urinary tract infection, because it is seen in many non-infectious conditions; 90% can be asymptomatic bacteriuria.⁶

Elderly people in nursing homes present with pyuria with no symptoms and may be misdiagnosed with urinary tract infection (UTI), which can lead to misuse of antibiotics, emergence of multidrug-resistant organisms, and adverse drug reactions. ⁷

Asymptomatic bacteriuria (ASB) 

This is defined as the presence of bacteria in the urine without signs and symptoms of UTIs.

Asymptomatic bacteriuria (ASB) is very common but often misdiagnosed in older adults: About 20– 50% of women in long-term care facilities, 10 – 40% of hospitalised elderly men, and especially in those with urinary catheters, diabetes, or neurogenic bladder^.8

The diagnostic criteria include:

• Two consecutive clean-catch urine samples that show the same bacterial strains in counts ≥ 105 CFU/mL in women or men ⁸

Pyuria frequently coexists with Asymptomatic bacteriuria in older adults. However, pyuria does not indicate infection and should not prompt antibiotic treatment on its own. When bacteria are absent from a culture is called Sterile pyuria and can occur from non-infectious diseases such as chronic kidney disease, malignancy, or interstitial cystitis.⁴

 Urinary incontinence and catheterisation

Urinary incontinence and the use of urinary catheters are common and key drivers of chronic pyuria in the elderly, especially those with:

• Advanced age of frailty
• Dementia
• Reduced mobility
• Long-term hospital stay
• Long-term indwelling catheters

Pyuria is mostly seen in individuals with urinary catheters. The presence of pyuria in these patients is often not predictive of symptomatic infection. Many catheterised patients have Asymptomatic bacteriuria with accompanying pyuria, which does not require treatment in the absence of symptoms. ⁹

The major reason for chronic pyuria in catheterisation is the formation of biofilm on the surface of the catheter; these biofilms cause:

• Harbours bacteria
• Chronic low-grade inflammation
• Resistant to antibiotics and immune clearance
• Leads to persistent pyuria and bacteriuria despite a lack of overt infection

Recommendation guidelines by the Infectious Disease Society of America (IDSA) in the management of urinary catheterisation in the elderly: 

Patients with pyuria and bacteriuria should not be treated unless there are signs and symptoms of a UTI, such as fever, suprapubic tenderness, flank pain, or change in mental status.

Routine screening for pyuria or bacteriuria in catheterised patients is not recommended.

Change the catheter once an infection is suspected, as this may disrupt biofilms and improve diagnostic accuracy.

Urinary incontinence does not cause pyuria directly, but is associated with:

• Increase poor perineal hygiene
• Increase the risk of urinary catheter use
• Increase the likelihood of asymptomatic bacteriuria
• Unnecessary urinalysis and antibiotic usage.

Proper continence guidelines and preventing needless catheterisation are crucial to decreasing pyuria-related misdiagnosis and overtreatment.⁹

Atrophic vaginitis

In postmenopausal women, a decrease in estrogen levels causes atrophic changes in the vaginal and lower bladder tissue. Patients usually will complain of the following:

• Frequent urination
• Urgency
• Mild pain on urination
• Vaginal dryness, burning, or pain
• Pyuria on urinalysis will yield no urine culture (sterile pyuria).

The dryness and discomfort can be managed with a topical vaginal estrogen. Antibiotics are not encouraged except in the presence of infection

Interstitial cystitis

Interstitial cystitis is also known as bladder pain syndrome, a persistent, non-infectious disease characterised by:

• Suprapubic pain or pelvic pain
• Increase urinary frequency
• Urgency
• Absence of infection

Some patients experience sterile pyuria, which is likely caused by persistent inflammation of the bladder wall.

Women are mostly affected, particularly older women, and often underdiagnosed due to symptoms overlapping with urinary tract infections.

Diagnosis is done with urine cultures, and results are persistently negative; cystoscopy may reveal bladder abnormalities such as Hunner’s lesions.

Use of antibiotics is prohibited because it can increase antimicrobial resistance if taken unnecessarily¹¹

Summary

Pyuria in older adults is a common condition with multifactorial causes. It is important to have an understanding of pyuria, differentiating between infectious and non-infectious pyuria. A treatment-based approach, supported by urine culture and consideration of comorbidity, is a key to management in older adults.