What is the appropriate workup and initial management for a 55-year-old man presenting with flank pain and gross hematuria?

Workup and Management of Flank Pain with Gross Hematuria in a 55-Year-Old Male

Order a non-contrast CT scan of the abdomen and pelvis immediately—this is the gold-standard imaging modality with 98-100% sensitivity and specificity for detecting urinary stones and will identify alternative diagnoses in approximately one-third of patients. 1

Immediate Clinical Assessment

Vital Signs and Red Flags

• Check vital signs immediately to exclude shock, hemodynamic instability, or fever, all of which mandate urgent hospital admission. 1, 2
• Fever ≥38°C with flank pain suggests acute pyelonephritis or obstructive pyelonephritis (a urologic emergency requiring immediate antibiotics and decompression). 3
• In patients over 60 years, maintain high suspicion for leaking abdominal aortic aneurysm, which can present with flank pain and hematuria. 2

Pain Characteristics

• Classic renal colic presents as severe, colicky, wave-like pain independent of body position, radiating to the groin or genitals with abrupt onset. 1
• Pain that varies with position suggests musculoskeletal origin rather than urolithiasis. 1

Rapid Analgesia

• Administer intramuscular diclofenac 75 mg (or equivalent NSAID) within 30 minutes of presentation. 1, 2
• Reassess pain control at 1 hour—failure to achieve adequate analgesia mandates immediate hospital admission. 1, 2

Laboratory Evaluation (Obtain Before or Concurrent with Imaging)

• Urinalysis with microscopy: Look for hematuria (present in 77-85% of stone cases), pyuria, bacteriuria, red blood cell casts (suggesting glomerulonephritis), and crystals. 3, 4
• Critical caveat: More than 20% of patients with confirmed urinary stones have negative urinalysis for hematuria—absence does not exclude stone disease. 1
• Urine culture: Obtain if fever, dysuria, or pyuria present. 1
• Serum creatinine: Assess baseline renal function. 1
• Complete blood count: Identify leukocytosis suggesting infection. 1

Imaging Strategy

First-Line: Non-Contrast CT Abdomen/Pelvis

• This is the definitive test with 98-100% sensitivity and specificity for stones of any size, location, or composition. 1
• Identifies alternative diagnoses (diverticulitis, appendicitis, AAA, renal cell carcinoma, pyelonephritis) in roughly one-third of patients presenting with flank pain. 1, 5
• Use low-dose CT protocols when available—these maintain 92-99% sensitivity while reducing radiation exposure. 1

When to Add Contrast-Enhanced CT

• Reserve contrast for suspected complicated infection (pyelonephritis with abscess, perinephric abscess) when fever and systemic symptoms are present. 1
• Use contrast if non-contrast CT is nondiagnostic or if clinical improvement does not occur after initial therapy. 1
• Contrast adds diagnostic information in only 5-18% of cases and alters management in merely 2-3% of patients. 1

Alternative Imaging (Ultrasound)

• Ultrasound has only 24-57% sensitivity for direct stone visualization, especially for stones <5 mm. 1
• However, ultrasound demonstrates up to 100% sensitivity for hydronephrosis, ureterectasis, and perinephric fluid. 1
• Absence of hydronephrosis on ultrasound makes larger ureteral stones (>5 mm) unlikely. 1
• Important pitfall: Within the first 2 hours of presentation, secondary signs of obstruction may not yet be apparent on ultrasound. 1

Differential Diagnosis Beyond Urolithiasis

Urologic Causes

• Acute pyelonephritis: Fever, flank pain, pyuria, bacteriuria—requires urgent antibiotics and admission if obstructed. 3
• Renal cell carcinoma: Can present with flank pain and hematuria; ultrasound may reveal abnormal masses prompting further investigation. 6
• Page kidney: Subcapsular hematoma causing renal compression and secondary hypertension—consider in hypertensive patients without trauma history. 7

Non-Urologic Causes (Identified on CT)

• Diverticulitis: Left-sided colonic diverticulitis frequently mimics renal colic. 1
• Abdominal aortic aneurysm: Especially in patients >60 years with cardiovascular risk factors. 2
• Inflammatory bowel disease: Can present with flank discomfort. 1

Management Based on CT Findings

If Urolithiasis Confirmed

• Stones <5 mm: Typically pass spontaneously—discharge with analgesia, alpha-blocker (tamsulosin), hydration instructions, and urine straining. 1
• Stones ≥5 mm or complete obstruction: Urgent urology referral within 7-14 days for consideration of intervention (ureteroscopy, lithotripsy). 1
• Infected obstructed system (fever + stone + hydronephrosis): Immediate admission for IV antibiotics and urgent decompression (percutaneous nephrostomy or ureteral stent). 1

If No Stone Found

• Manage according to alternative diagnosis identified on CT. 1
• If CT is entirely normal but gross hematuria persists, urgent urologic referral is mandatory because gross hematuria confers >10% risk of underlying urinary tract malignancy. 3
• Critical pitfall: Malignancy-related hematuria is typically painless, but the combination of pain and gross hematuria in a 55-year-old male still requires cystoscopy and upper tract imaging to exclude bladder cancer or upper tract urothelial carcinoma. 8, 3

Follow-Up and Safety Net

• Telephone follow-up 1 hour after initial analgesia administration. 1
• Fast-track radiology within 7 days if managed outpatient. 1
• Instruct patient to return immediately if fever develops, pain becomes uncontrollable, or inability to urinate occurs. 1
• Do not attribute hematuria solely to stones—comprehensive urologic evaluation is required, especially in patients >35 years with risk factors for malignancy (smoking, occupational exposures). 3