What is the most appropriate investigation for a 67‑year‑old man presenting with hematuria, right flank pain and tenderness, and an enlarged prostate?

Most Appropriate Investigation for Hematuria with Flank Pain in a 67-Year-Old Male

CT KUB (non-contrast) is the most appropriate initial investigation for this patient presenting with hematuria, right flank pain and tenderness, and an enlarged prostate.

Rationale for CT KUB as First-Line Investigation

This 67-year-old male with hematuria (20 RBC/HPF), unilateral flank pain, and flank tenderness requires urgent imaging to exclude both urologic malignancy and obstructive uropathy. 1, 2

Why CT KUB is Superior to Other Options

• Non-contrast CT KUB has sensitivity and specificity both exceeding 90% for detecting urinary tract stones, renal masses, and upper tract pathology that could explain this presentation 1

• The American College of Radiology explicitly recommends CT as the preferred imaging modality for painful hematuria with suspected urolithiasis or renal pathology, given its superior diagnostic accuracy 1

• CT KUB provides comprehensive evaluation beyond just stones—it can detect renal cell carcinoma, upper tract urothelial carcinoma, UPJ obstruction, and other anatomic abnormalities that present with hematuria and flank pain 1

• In elderly patients (≥60 years) with hematuria, malignancy risk is significantly elevated, making comprehensive upper tract imaging mandatory 2

Why Plain X-ray KUB is Inadequate

• Plain radiography has inadequate sensitivity (only 59%) for stone detection and provides no information about degree of obstruction, hydronephrosis, soft tissue masses, or renal parenchymal disease 1

• X-ray KUB cannot evaluate for renal masses or upper tract urothelial carcinoma, both critical differential diagnoses in a 67-year-old male with hematuria 1, 2

Why Cystoscopy Should Not Be First

• While cystoscopy is mandatory for complete hematuria evaluation in this age group, it must be preceded by upper tract imaging because this patient has unilateral flank pain and tenderness—localizing signs that suggest upper tract pathology (kidney or ureter) rather than bladder disease 2

• Cystoscopy evaluates only the bladder, urethra, and ureteral orifices—it cannot visualize the renal parenchyma, collecting system, or ureters where this patient's pathology likely originates 2

• The combination of flank pain with hematuria strongly suggests nephrolithiasis, renal mass, or upper tract urothelial carcinoma—all of which require CT imaging for diagnosis 1, 2

Risk Stratification and Malignancy Concern

This patient has multiple high-risk features for urologic malignancy that mandate comprehensive evaluation: 2

• Age 67 years (males ≥60 years are automatically high-risk) 2
• Gross hematuria carries 30-40% malignancy risk; even microscopic hematuria (20 RBC/HPF) in this age group carries significant cancer risk 2
• Enlarged prostate on examination raises concern for both benign prostatic hyperplasia and prostate cancer, but does not exclude concurrent bladder or upper tract malignancy 2

Complete Diagnostic Algorithm

Immediate Next Steps (After CT KUB)

1. If CT KUB shows obstructing stone: Manage according to stone size, location, and degree of obstruction; patient still requires cystoscopy within 3-6 months to complete hematuria evaluation 1, 2

2. If CT KUB shows renal mass: Urgent urology referral for further characterization (multiphasic contrast-enhanced CT or MRI) and management 1, 2

3. If CT KUB shows upper tract urothelial lesion: Urgent urology referral; may require CT urography with contrast and ureteroscopy with biopsy 3, 4

4. If CT KUB is negative: Proceed immediately to flexible cystoscopy to evaluate for bladder cancer, which is the most frequently diagnosed malignancy in hematuria cases 2

Why This Patient Needs Both CT and Cystoscopy Eventually

• Complete hematuria evaluation in a 67-year-old male requires both upper tract imaging (CT) and lower tract evaluation (cystoscopy) 2

• The flank pain localizes concern to the upper tract, making CT the logical first step 1

• Even if CT explains the hematuria (e.g., stone), cystoscopy remains mandatory because bladder cancer can coexist with other urologic pathology, and this patient's age and hematuria place him at high risk 2

Critical Pitfalls to Avoid

• Never attribute hematuria solely to benign prostatic hyperplasia without complete urologic evaluation—BPH does not exclude concurrent malignancy 2

• Do not delay imaging waiting for "conservative management" or repeat urinalysis—delays beyond 9 months are associated with worse cancer-specific survival 2

• Do not assume the enlarged prostate explains everything—upper tract pathology (stones, masses, obstruction) must be excluded first given the flank pain 1, 2

• Absence of trauma history does not reduce concern for serious pathology in a 67-year-old with hematuria 2

Summary of Investigation Sequence

The correct diagnostic pathway is:

1. CT KUB (non-contrast) NOW to evaluate kidneys, ureters, and identify cause of flank pain 1
2. Flexible cystoscopy (timing depends on CT findings—urgent if CT negative, can be scheduled if obstructing stone found) 2
3. Serum creatinine to assess renal function 2
4. Urine culture if not already done, though infection does not explain unilateral flank tenderness 2

This algorithmic approach ensures timely diagnosis of life-threatening conditions (renal cell carcinoma, upper tract urothelial carcinoma, obstructing stone with infection) while completing the mandatory hematuria evaluation for bladder cancer. 1, 2