What is the appropriate workup and management for a patient presenting with right flank pain?

Workup and Management of Right Flank Pain

For patients presenting with right flank pain, non-contrast CT of the abdomen and pelvis is the most appropriate initial imaging study due to its high diagnostic accuracy for urolithiasis and other potential causes. 1

Initial Evaluation

• Right flank pain is a common presentation that may indicate urinary tract pathology (particularly urolithiasis) but can also represent various other conditions affecting nearby structures 1, 2
• Key clinical features to assess include:
  • Pain characteristics (sudden onset, colicky, radiation to groin)
  • Associated symptoms (hematuria, nausea, vomiting, fever)
  • Vital signs (hypertension may suggest conditions like Page kidney) 3

Diagnostic Imaging Algorithm

First-Line Imaging

• Non-contrast CT of abdomen and pelvis is the imaging modality of choice for right flank pain evaluation 1
  • Advantages:
    • Detects ureteral stones with 98-100% sensitivity and specificity regardless of size, location, or composition 1
    • Identifies extraurinary causes of flank pain in approximately one-third of patients 1
    • Does not require contrast agent (avoiding nephrotoxicity and allergic reactions) 1
    • Time-efficient (completed within 5 minutes) 1

Alternative Imaging Options

• Ultrasonography may be considered in specific situations:

  • When combining findings of pyeloureteral dilation, direct stone visualization, and absence of ureteral ejaculation, sensitivity can reach 96% 1
  • When combined with KUB (kidney, ureter, bladder) radiography, specificity reaches 100% with 89% sensitivity 4
  • Particularly useful when radiation exposure is a concern 5

• MRI may be appropriate in cases where CT is contraindicated:

  • Similar sensitivity (85%) and specificity (81%) to ultrasonography for certain conditions 5
  • Useful for visualizing hepatic and biliary abnormalities not well-characterized on ultrasound 5

Differential Diagnosis

• Urolithiasis: Most common cause of acute flank pain 1, 2

  • Presents with sudden-onset, severe pain that may radiate to groin
  • Often associated with hematuria and nausea/vomiting

• Other urinary tract conditions:

  • Pyelonephritis
  • Renal abscess
  • Page kidney (compression of renal parenchyma causing secondary hypertension) 3

• Non-urinary causes:

  • Right colonic diverticulitis 5
  • Appendicitis (especially retrocecal) 5
  • Intestinal obstruction 5
  • Hepatobiliary conditions 5

Management Approach

• For confirmed urolithiasis:

  • Small stones (<5mm): Conservative management with pain control and hydration to facilitate passage 2, 6
  • Larger stones or those causing significant obstruction: Urological intervention may be necessary (stenting, lithotripsy, or surgical removal) 2
  • Antibiotics if signs of infection are present 2

• For non-stone pathology:

  • Treatment directed at the specific diagnosis identified by imaging
  • Surgical consultation for conditions like appendicitis or diverticulitis 5
  • Hypertension management for conditions like Page kidney 3

Important Considerations and Pitfalls

• Do not assume all flank pain with hematuria is urolithiasis - consider the full differential diagnosis 3
• Hydronephrosis on imaging requires urgent attention as it may lead to kidney damage if obstruction is not relieved 2
• Traditional intravenous urography (IVU) has been largely replaced by CT due to contrast-related risks and lower diagnostic accuracy 1
• When evaluating right flank pain that could be referred from the lower quadrant, consider appendicitis in the differential diagnosis, especially with fever and leukocytosis 5