Do you treat for a Urinary Tract Infection (UTI) in a patient with symptoms but only leukocyte esterase noted on Urinalysis (UA)?

Treatment of UTI with Symptoms and Only Leukocyte Esterase on UA

Patients with UTI symptoms and only leukocyte esterase positivity on urinalysis should receive antibiotic treatment, as leukocyte esterase has good sensitivity (84%) for detecting UTIs even when nitrites are negative. 1

Diagnostic Value of Leukocyte Esterase

• Leukocyte esterase has higher sensitivity (83-84%) but lower specificity (78%) compared to nitrites (sensitivity 53%, specificity 98%) 1
• The presence of leukocyte esterase indicates pyuria, which correlates with urinary tract inflammation 1
• While the combination of both leukocyte esterase and nitrite provides the highest diagnostic utility (combined sensitivity 93%), leukocyte esterase alone is still a valuable screening tool 1, 2

Treatment Algorithm

1. Assess symptoms:

   • Typical symptoms: dysuria, frequency, urgency, incontinence
   • In older patients: may present with atypical symptoms (altered mental status, functional decline, fatigue) 3

2. Interpret urinalysis findings:

   • Positive leukocyte esterase + symptoms = treat for UTI
   • Negative leukocyte esterase AND negative nitrite + symptoms = consider alternative diagnoses 3

3. Consider patient factors:

   • Higher Charlson Comorbidity Index scores correlate with higher likelihood of true UTI 4
   • Elderly patients may have atypical presentations but still benefit from treatment when symptomatic 3

Antibiotic Selection

For uncomplicated UTIs with positive leukocyte esterase and symptoms:

• First-line options: trimethoprim-sulfamethoxazole, nitrofurantoin, or cephalexin 1
• Treatment duration: 3-5 days for uncomplicated cystitis; 7-14 days for complicated UTIs 1
• Consider local resistance patterns when selecting empiric therapy 4

Important Considerations and Caveats

• False positives: Leukocyte esterase can be falsely positive with non-infectious causes of pyuria, contamination from vaginal secretions, or certain medications 1
• Organism variation: Some organisms like Klebsiella spp. and Enterococcus spp. may cause UTIs with less pyuria (and potentially weaker leukocyte esterase positivity) 5
• Age considerations: In elderly patients, the specificity of urine dipstick tests ranges from 20% to 70%, requiring more careful interpretation 3
• Avoid overtreatment: Asymptomatic bacteriuria should not be treated, especially in elderly patients 1

When to Obtain Urine Culture

• When diagnosis is uncertain (moderate probability of UTI)
• In complicated UTIs (pregnancy, immunocompromised patients, etc.)
• When symptoms persist despite empiric therapy
• In patients with recurrent UTIs 1, 6

By following this approach, you can appropriately identify and treat patients with UTI symptoms and positive leukocyte esterase, while avoiding unnecessary antibiotic use in those without true infection.