What is the diagnosis and treatment for a patient with right-sided abdominal pain radiating to the back for 2 days?

Right-Sided Abdominal Pain Radiating to Back: Diagnosis and Management

Immediate Diagnostic Approach

Order a CT scan of the abdomen and pelvis with IV contrast immediately, as this is the gold standard imaging modality for evaluating right-sided abdominal pain with unclear etiology and will identify the diagnosis in the vast majority of cases. 1

Key Differential Diagnoses to Consider

The combination of right-sided abdominal pain radiating to the back over 2 days suggests several critical possibilities that require urgent evaluation:

• Acute appendicitis (including retrocecal appendicitis, which classically presents with right upper quadrant or flank pain radiating to the back) 2
• Acute cholecystitis or biliary pathology (right upper quadrant pain radiating to back is classic) 1, 3
• Nephrolithiasis or pyelonephritis (right flank/back pain with anterior radiation) 1, 4
• Right-sided colonic diverticulitis (less common but occurs, especially in younger patients) 1
• Pancreatitis (can present with right-sided pain radiating to back) 1
• Perforated viscus or abscess (especially if fever or peritoneal signs present) 1

Why CT with IV Contrast is Essential

• CT changes the leading diagnosis in 49% of patients and alters management in 42% of cases with nonlocalized or atypical abdominal pain 1
• CT has >95% sensitivity for detecting appendicitis, diverticulitis, and most serious abdominal pathology 1
• CT can identify alternative diagnoses in 94% of non-appendiceal cases, including renal, pancreatic, and biliary pathology 5
• Contrast enhancement is critical for detecting bowel wall inflammation, abscesses, vascular complications, and differentiating inflammatory from non-inflammatory conditions 1, 6

Clinical Assessment While Awaiting Imaging

Obtain focused history and examination for:

• Fever, tachycardia, or signs of sepsis (suggests infection, perforation, or abscess) 1
• Urinary symptoms or hematuria (suggests nephrolithiasis or pyelonephritis) 4
• Nausea, vomiting, anorexia (common in appendicitis, cholecystitis, pancreatitis) 7, 2
• Right costovertebral angle tenderness (suggests renal pathology) 4
• Murphy's sign (suggests cholecystitis) 3
• Peritoneal signs (rebound, guarding—suggests perforation or advanced inflammation) 7

Initial Laboratory Tests

Order immediately while arranging CT:

• Complete blood count (leukocytosis suggests infection/inflammation) 1
• Comprehensive metabolic panel (assess renal function, electrolytes) 6
• Lipase (if pancreatitis suspected) 1
• Urinalysis (pyuria suggests UTI/pyelonephritis; hematuria suggests stone) 4
• Pregnancy test in all women of reproductive age (mandatory before CT) 5, 6

Alternative Imaging Only in Specific Circumstances

• Ultrasound is appropriate ONLY if:

  • Pregnancy is confirmed or cannot be excluded 1, 5
  • Strong clinical suspicion for cholecystitis or biliary pathology 1
  • Patient is young and renal stone is highly suspected 6

• MRI without contrast if:

  • Patient is pregnant and ultrasound is non-diagnostic (96.8% sensitivity for appendicitis in pregnancy) 5
  • Severe renal impairment contraindicates IV contrast 6

Management Algorithm Based on CT Findings

If CT Shows Appendicitis:

• Immediate surgical consultation for appendectomy 5, 2
• Retrocecal appendicitis may present with right upper quadrant or flank pain and can be missed on ultrasound but is reliably detected on CT 2

If CT Shows Cholecystitis:

• Surgical consultation for cholecystectomy (typically within 72 hours for acute cholecystitis) 1

If CT Shows Nephrolithiasis:

• Urology consultation if stone >5mm, complete obstruction, or signs of infection 4
• Conservative management with hydration and analgesia for smaller stones 4

If CT Shows Diverticulitis:

• Antibiotics and bowel rest for uncomplicated cases 1
• Surgical consultation if perforation, abscess, or peritonitis present 1

If CT Shows Pancreatitis:

• Admit for IV fluids, bowel rest, analgesia, and monitoring 1

If CT is Negative:

• Consider functional pain, musculoskeletal causes, or early/evolving pathology 8
• Do not assume pain is benign—clinical reassessment in 12-24 hours is mandatory if symptoms persist 1

Critical Pitfalls to Avoid

• Do not delay CT beyond 12 hours if serious pathology is suspected, as conditions like perforated appendicitis, mesenteric ischemia, or abscess require urgent intervention 6
• Do not order ultrasound as the sole initial study in non-pregnant adults with unclear diagnosis, as it has inadequate sensitivity and will likely require follow-up CT anyway 5
• Do not rely on plain radiography, as it has minimal diagnostic value except for detecting free air or bowel obstruction 1
• Do not assume back pain means musculoskeletal pathology—abdominal visceral pathology frequently radiates to the back 8, 2
• Do not withhold IV contrast due to mild-moderate renal impairment unless patient is dialysis-dependent or eGFR <30, as diagnostic benefit outweighs risk 6
• Do not forget pregnancy testing in all reproductive-age women before CT, as radiation exposure and IV contrast have fetal implications 5, 6