From the Guidelines
A mildly positive leukocyte esterase with otherwise negative urinalysis findings in an HIV patient suggests possible asymptomatic pyuria, and I recommend collecting a clean-catch urine culture to determine if bacteria are present before starting antibiotics. This finding warrants further evaluation but doesn't necessarily indicate a urinary tract infection requiring immediate treatment. The patient's HIV status, particularly their CD4 count and viral load, should be considered, as immunosuppression can alter the presentation of infections 1. According to the guidelines for the management of persons infected with HIV, kidney function is abnormal in up to 30% of HIV-infected patients, and HIV-associated nephropathy is a relatively common cause of end-stage renal disease in this population 1.
The positive leukocyte esterase indicates the presence of white blood cells in urine, which can occur due to UTI, but also from contamination during collection, inflammation near the urinary tract, or other infections related to HIV. If the patient has symptoms like dysuria, frequency, or urgency, empiric treatment with trimethoprim-sulfamethoxazole (one double-strength tablet twice daily for 3-5 days) or nitrofurantoin (100mg twice daily for 5-7 days) could be considered while awaiting culture results. Regular follow-up is essential, especially if symptoms develop or persist. Additionally, screening for chronic kidney disease (CKD) is crucial in HIV-infected patients, and an estimate of creatinine clearance or GFR should be annually performed to screen for renal dysfunction 1.
Key considerations in managing this patient include:
- Collecting a clean-catch urine culture to determine if bacteria are present
- Considering the patient's CD4 count and viral load status
- Screening for CKD and estimating creatinine clearance or GFR annually
- Monitoring for symptoms like dysuria, frequency, or urgency, and treating empirically if necessary
- Regular follow-up to assess for development or persistence of symptoms.
From the Research
Urinalysis Results
- A mildly positive leukocyte esterase result with all other items on urinalysis negative in a patient with HIV may indicate a potential urinary tract infection (UTI) 2, 3.
- However, a negative urinalysis result does not rule out a UTI, especially if the patient has a strong suspicion of a UTI 2.
- The presence of leukocyte esterase in the urine can be a predictive value to detect bacterial growth in urine culture 3.
Leukocyte Esterase and HIV
- Elevated urinary leukocyte esterase has been associated with increased HIV sexual transmission risks in men receiving antiretroviral therapy 4.
- A simple over-the-counter urine test for leukocyte esterase may serve as an indicator of sexual HIV infectiousness 4.
Diagnostic Value of Leukocyte Esterase
- The sensitivity and specificity of a urine leukocyte esterase dipstick test for the diagnosis of UTI have been reported to be 63.6% and 44.2%, respectively 5.
- The presence of pyuria has been shown to have a higher sensitivity (95.6%) and specificity (60.9%) for positive urine culture compared to the dipstick test 5.
- A false positive leukocyte esterase test can be associated with vulvovaginitis in prepubertal girls and phimosis in boys 6.
Clinical Implications
- A detailed history and physical examination can help avoid unnecessary tests and treatments for UTI in patients with a false positive leukocyte esterase test 6.
- The clinical predictive value of the urine leukocyte esterase test positivity should be considered in the context of other clinical and laboratory parameters 6.