Can UTI Cause Hematuria?
Yes, urinary tract infection is a well-established and common benign cause of hematuria, recognized by the American College of Radiology as one of the primary urogenic causes of blood in the urine. 1
Understanding UTI as a Cause of Hematuria
Infection is explicitly listed among the common benign urogenic causes of hematuria, alongside urolithiasis and benign prostatic hypertrophy. 1 The mechanism involves inflammation of the urinary tract mucosa, which leads to bleeding that can manifest as either microscopic or gross hematuria. 2
Clinical Presentation
- Hematuria from UTI typically presents with accompanying urinary symptoms including dysuria (painful urination), increased frequency, urgency, and suprapubic pain. 2
- The urine will show pyuria (white blood cells) and bacteriuria (bacteria) on urinalysis, which helps distinguish infectious hematuria from other causes. 3
- Upper tract infections (pyelonephritis) may present with hematuria plus systemic symptoms such as fever, flank pain, and costovertebral angle tenderness. 2
Critical Clinical Approach
When UTI is Suspected as the Cause
Patients with suspected UTI as the cause of microhematuria should have urine cultures performed, preferably before antibiotic therapy, to confirm the infection. 1 This confirmation is essential because:
- The definition of microhematuria specifically requires "no evidence of infection" when establishing the diagnosis, meaning true microhematuria is defined as occurring in a properly collected, noncontaminated specimen without pyuria or bacteriuria. 1
- If infection is present, the hematuria may resolve with appropriate antibiotic treatment, and further workup may be deferred. 1
Important Pitfall: Do Not Assume UTI Excludes Malignancy
The presence of a positive urine culture does NOT decrease the likelihood of having a urologic malignancy. 4 This is a critical clinical pitfall:
- In one prospective study of 161 patients with hematuria and positive urine culture, 20% had a urologic malignancy diagnosed, including 12% with metastatic disease at presentation. 4
- This risk was comparable to the 24% malignancy rate in patients without UTI. 4
- Therefore, prompt evaluation should not be delayed in patients with hematuria and concurrent UTI, particularly in those with risk factors for malignancy. 4
Risk Stratification Algorithm
Patients Who Can Defer Extensive Workup
Patients without risk factors and with an identified UTI as the benign cause of microhematuria are unlikely to benefit from complete imaging workup. 1 This applies when:
- No risk factors for malignancy are present (age <35, no smoking history, no occupational exposures)
- Urine culture confirms infection
- Hematuria resolves after treatment of the UTI
Patients Who Require Full Evaluation Despite UTI
Full urologic workup is mandatory regardless of UTI presence when: 1
- Gross hematuria is present (30-40% malignancy risk) 1
- Age >35 years 1
- Male gender 1
- Smoking history 3
- Occupational chemical exposure 1
- History of chronic urinary tract infection 1
- Irritative voiding symptoms persist after UTI treatment 1
Special Consideration in Women
Interstitial cystitis should be considered in women with chronic pelvic pain and microhematuria, as this diagnosis is prevalent but often difficult to diagnose, and hematuria may occur in up to 30-41% of these patients. 1, 5
Bottom Line for Clinical Practice
Treat the UTI first with appropriate antibiotics after obtaining urine culture. 1 If hematuria persists after documented clearance of infection, or if any malignancy risk factors are present, proceed immediately with full urologic evaluation including cystoscopy and imaging. 1, 4 Never use the presence of UTI as justification to delay evaluation in high-risk patients. 4