Management of Microscopic Hematuria in a 37-Year-Old Female with Hydronephrosis
The next step in managing this 37-year-old female with microscopic hematuria, occasional right flank pain, and mild bilateral hydronephrosis should be to proceed with the planned CT abdomen/pelvis without contrast to evaluate for urolithiasis, followed by the scheduled urinalysis, urine culture, and urine cytology. 1
Diagnostic Approach for Microscopic Hematuria
Initial Evaluation
- The patient's presentation with microscopic hematuria (RBCs 3-5), occasional right flank pain, and bilateral hydronephrosis (right > left) strongly suggests urolithiasis as a potential cause 1, 2
- CT imaging without contrast is the preferred initial study for suspected urolithiasis, with sensitivity of 94-98% for detection of renal stones compared to 52-59% for intravenous urography and 19% for ultrasonography 1
- The scheduled urinalysis, urine culture, and urine cytology are appropriate follow-up tests to rule out infection and evaluate for potential malignancy 1, 3
Risk Stratification
- This patient would be classified as low-risk for urothelial malignancy based on her age (<50 years), RBC count (3-10 RBC/HPF), and absence of gross hematuria or significant smoking history 1
- Despite being low-risk, the presence of hydronephrosis warrants thorough evaluation as it suggests possible obstructive uropathy 3, 4
Imaging Considerations
CT Protocol Selection
- For this patient with suspected urolithiasis, a non-contrast CT is appropriate as the initial imaging study 1
- If the non-contrast CT demonstrates urolithiasis in a patient who is at low risk for underlying malignancy (as in this case), no further scanning is needed 1
- If no urinary calculi are detected, consideration should be given to CT with intravenous contrast to better evaluate the urothelium 1, 5
Rationale for Non-Contrast CT
- Non-contrast CT has the highest sensitivity for detecting urinary stones and is the best modality for evaluation of urolithiasis, renal and perirenal infections, and associated complications 1
- Research shows that patients with microscopic hematuria but without stones on imaging may have a higher rate of moderate-to-severe hydronephrosis (42%) compared to those with microscopic hematuria and stones (25%) 4
Additional Evaluation Considerations
Cystoscopy Recommendations
- Based on the patient's age (<40 years) and low risk for bladder cancer, initial cystoscopy may be deferred, but urinary cytology should be performed as planned 1
- Cystoscopy is recommended for patients >40 years of age or those with risk factors for bladder cancer, but may not be necessary in this 37-year-old female without risk factors 1
Follow-up Plan
- If the CT scan confirms urolithiasis, management should focus on stone treatment and prevention 3
- If the CT is negative for stones but hydronephrosis persists, further imaging with contrast-enhanced CT or MR urography may be warranted to evaluate for other causes of obstruction 1
- For patients with persistent microscopic hematuria after negative evaluation, repeat urinalysis at 6,12,24, and 36 months is recommended 6
Common Pitfalls and Caveats
- Do not assume that microscopic hematuria during menstruation is solely due to menstrual contamination; proper urologic evaluation is still necessary 3
- Patients without microscopic hematuria can still have significant urologic disease, as studies show that patients with ureterolithiasis without hematuria may have larger stones and more severe hydronephrosis 4
- Avoid unnecessary testing in low-risk patients; selective ordering of tests based on clinical presentation can result in significant cost savings without compromising patient care 7
- Be aware that while CT urography has high sensitivity for upper tract imaging, non-contrast CT may miss some urothelial lesions, though the risk is very low (0.2%) in patients presenting with symptoms of urolithiasis 5