What is the likely diagnosis and treatment for a patient with microscopic hematuria, 2 to 4 pus cells per high power field (hpf), and leukopenia (low White Blood Cell (WBC) count)?

Urinary Tract Infection with Microscopic Hematuria

The combination of microscopic hematuria with 2-4 pus cells per HPF and low WBC count most likely indicates a urinary tract infection that requires antibiotic treatment, with the leukopenia representing a systemic finding unrelated to the urinary pathology. 1

Initial Diagnostic Interpretation

The urinalysis findings point toward a urinary tract infection as the primary diagnosis:

• Pyuria (2-4 WBC/HPF) combined with microscopic hematuria strongly suggests UTI, particularly when bacteria are present on microscopy 1
• The presence of both red blood cells and white blood cells in urine is characteristic of infectious/inflammatory processes affecting the urinary tract 1
• Leukocyte esterase serves as a surrogate marker for pyuria with 83-94% sensitivity for detecting UTIs, though specificity is lower at 78-91% 1

Important caveat: The peripheral leukopenia (low systemic WBC) is a separate finding that does not negate the local inflammatory response in the urinary tract. The pus cells in urine represent local leukocyte migration to the site of infection, independent of circulating WBC counts.

Treatment Approach

Initiate empiric antibiotic therapy immediately based on local resistance patterns 1:

• Start antibiotics without waiting for culture results in symptomatic patients
• Obtain urine culture before starting antibiotics when possible to guide therapy if symptoms persist 2
• Repeat urinalysis 6 weeks after completing antibiotic treatment to confirm resolution of hematuria 1

Post-Treatment Evaluation Algorithm

If hematuria resolves after antibiotic treatment: No additional urologic evaluation is necessary 1

If hematuria persists after treatment, proceed with complete urologic evaluation 1:

1. Measure serum creatinine to assess renal function 1
2. Examine urinary sediment for dysmorphic RBCs and red cell casts to determine if glomerular origin 1
3. Obtain upper urinary tract imaging (CT urography preferred) to detect renal cell carcinoma, transitional cell carcinoma, urolithiasis, or renal infection 1
4. Consider voided urinary cytology if risk factors present (see below) 1

Risk Stratification for Persistent Hematuria

Assess for high-risk features that warrant more aggressive evaluation if hematuria persists 2:

• Age >40 years 2
• Smoking history 2
• Occupational exposure to chemicals or dyes (benzenes, aromatic amines) 2
• History of gross hematuria 2
• History of urologic disorders 2
• Irritative voiding symptoms 2
• Analgesic abuse 2
• History of pelvic irradiation 2

Patients with these risk factors warrant thorough evaluation if hematuria persists after infection treatment 1.

Critical Clinical Pitfalls

Do not attribute hematuria solely to UTI without confirming resolution: Even when UTI is present, underlying malignancy can coexist, particularly in high-risk patients 2. The 6-week post-treatment urinalysis is mandatory to ensure the hematuria was truly infection-related 1.

Do not defer evaluation based on leukopenia: The systemic low WBC count requires separate hematologic evaluation but should not delay treatment of the urinary tract infection or subsequent hematuria workup if it persists 1.

Confirm microscopic hematuria by microscopy, not dipstick alone: Dipstick has limited specificity (65-99%) and requires confirmation with microscopic examination showing ≥3 RBCs per HPF 2.