CT Interpretation for Left Flank Pain with Intermittent Hematuria
For this 67-year-old woman with persistent left flank pain and history of intermittent hematuria, the ordered CT scan should be a non-contrast CT abdomen and pelvis as the initial study, which is the reference standard for detecting urolithiasis with 97% sensitivity and will also identify most alternative causes of her symptoms 1.
Primary Diagnostic Approach
The clinical presentation—left flank pain, intermittent hematuria over years, and deeper pain distinct from her known disc disease—strongly suggests urolithiasis as the leading diagnosis. Non-contrast CT is currently the reference standard for evaluating suspected stone disease 1. This protocol will:
- Detect nearly all types of urinary calculi regardless of composition
- Assess stone burden and location
- Identify hydronephrosis or obstruction
- Reveal alternative diagnoses in 5-18% of cases 1
Key CT Findings to Evaluate
When interpreting the CT results, systematically assess:
For urolithiasis (most likely):
- Stone location, size, and density (Hounsfield units)
- Degree of hydronephrosis or hydroureter
- Perinephric stranding indicating acute obstruction
- Secondary signs: rim sign, tissue rim sign around ureter
For alternative diagnoses:
- Adrenal pathology: Carefully examine both adrenal glands, as hemorrhagic adrenal infarction can present with acute flank pain and may show only subtle enlargement or reduced enhancement on initial imaging 2. This is an important pitfall—early unilateral adrenal infarction may be missed.
- Pyelonephritis: Look for striated nephrogram, wedge-shaped areas of decreased enhancement, perinephric fat stranding 3
- Emphysematous infection: Gas in collecting system, ureter, or renal parenchyma 4
- Renal masses: Any solid or complex cystic lesions requiring further characterization 5
- Vascular causes: Renal infarction, hemorrhage
Important Clinical Caveats
The recent cervical epidural (3 days prior) is a red flag. While her pain predates this procedure, ensure the CT extends high enough to exclude retroperitoneal hematoma from the epidural procedure, though this would typically cause more diffuse symptoms.
The history of intermittent hematuria over many years makes this evaluation appropriate even without current hematuria. For patients with risk factors and recurrent symptoms, CT remains indicated 6.
Regarding contrast administration: The non-contrast study ordered is appropriate for initial evaluation. Adding IV contrast would change management in only 2-3% of stone cases 1, but if the non-contrast CT is negative for stones, consider CT urography (CTU) with contrast to evaluate for urothelial malignancy given her age and chronic intermittent hematuria history 5, 7, 8. CTU is highly accurate for detecting upper tract urothelial carcinomas and would be the next step if stones are excluded.
Interpretation Algorithm
If stones are present: Document size, location, density. Stones >5mm or causing significant obstruction may require intervention. Assess for complications (infection, complete obstruction).
If no stones identified: The differential broadens significantly. Review for:
If CT is negative: Given chronic intermittent hematuria, strongly consider CTU with contrast as follow-up to exclude urothelial malignancy, which is a critical diagnosis not to miss in this age group 8.
Pre-Travel Considerations
Given her imminent international travel, expedite the CT interpretation and ensure follow-up labs (CBC, CMP, calcium, uric acid, CRP) are reviewed concurrently. If a stone is identified but small (<5mm) without obstruction, she may travel with analgesics and hydration instructions. If obstruction, infection, or alternative serious pathology is found, travel should be deferred until definitively managed.
The combination of imaging and laboratory results will guide whether she can safely travel or requires urgent intervention before departure.