Management of Abdominal Pain with Trace Hematuria
For a patient with abdominal pain and trace (microscopic) hematuria, the primary differential is urolithiasis, and ultrasound of the kidneys and bladder should be the initial imaging modality, with CT reserved for cases where ultrasound is negative but clinical suspicion remains high.
Clinical Context and Differential Diagnosis
The combination of abdominal pain and hematuria most commonly suggests urolithiasis as the primary diagnosis, though tumor and ureteropelvic junction obstruction must also be considered 1. Importantly, a significant number of pediatric patients with urolithiasis do not have hematuria, so its presence is supportive but not required for the diagnosis 1.
Initial Diagnostic Approach
History and Physical Examination Focus
- Document the character and location of pain: Colicky flank pain radiating to the groin suggests stone disease, while constant suprapubic pain may indicate bladder pathology 1
- Assess for trauma history: Even minor trauma can cause significant injury if renal anomalies are present (occurring in 1-4% of the population) 1
- Exclude infection: Obtain urine culture even with negative dipstick, as lower bacterial levels may be clinically significant 2
- Rule out benign causes: Recent vigorous exercise, medications (anticoagulants), and menstruation can cause transient hematuria 3
Laboratory Evaluation
- Urinalysis with microscopy: Assess RBC morphology (dysmorphic RBCs suggest glomerular source), presence of casts, proteinuria, and white blood cells 3
- Urine culture: Mandatory to exclude infection as the cause 2
- Serum creatinine: To assess renal function and help differentiate glomerular from non-glomerular causes 3
Imaging Strategy
First-Line Imaging: Ultrasound
Ultrasound of the kidneys and bladder is the appropriate initial imaging test for most patients with painful hematuria 1. While US has limited sensitivity for detecting stones (finding only 75% of all urinary tract stones and 38% of ureteral stones), it avoids radiation exposure and is widely available 1.
When to Proceed to CT
CT without contrast should be obtained when 1:
- Ultrasound is negative but clinical suspicion for urolithiasis remains high
- Detection of a stone would impact treatment decisions
- The patient has recurrent symptoms with negative prior workup
CT has sensitivity and specificity both above 90% for stone detection and can be performed with very low radiation doses using modern iterative reconstruction algorithms 1.
Critical Decision Points Based on Hematuria Severity
Trace/Microscopic Hematuria (Your Patient)
- Does NOT require emergency imaging in the absence of trauma, hemodynamic instability, or concerning mechanism of injury 1
- Start with ultrasound as described above 1
- Conservative management is appropriate while awaiting imaging results
Gross Hematuria
- Requires urgent evaluation with contrast-enhanced CT and urologic referral due to high malignancy risk (30-40%) 3
- Mandatory urologic consultation even if bleeding is self-limited 3
Trauma-Related Considerations
If there is ANY history of trauma (even seemingly minor):
- Isolated microscopic hematuria without clinical findings of visceral trauma does not need emergency investigation 1
- Imaging is indicated only if: ≥50 RBCs per high-power field, hypotension, or significant deceleration mechanism 1
- Gross hematuria after trauma mandates contrast-enhanced CT to evaluate for renal injury 1
Common Pitfalls to Avoid
- Do not assume anticoagulation explains the hematuria: All hematuria requires evaluation regardless of anticoagulant use 3
- Do not skip urine culture: Infection must be definitively excluded even with negative dipstick 2
- Do not order MRI, VCUG, or arteriography: These are not appropriate for initial evaluation of painful hematuria 1
- Do not use plain radiography alone: It has only 59% sensitivity for stone detection 1
Follow-Up Protocol
For patients with negative initial evaluation: