What is the appropriate evaluation and management for a patient presenting with right-sided abdominal pain and a remote history of appendectomy?

Evaluation and Management of Right-Sided Abdominal Pain with Remote Appendectomy History

Order CT abdomen and pelvis with IV contrast immediately—this is the definitive diagnostic test that will identify the cause of pain, whether stump appendicitis, adhesive bowel obstruction, or alternative pathology, with 85.7-100% sensitivity and 94.8-100% specificity. 1, 2

Why CT is Essential in This Clinical Scenario

Your patient's history of appendectomy years ago does not exclude appendiceal pathology. Two critical entities must be considered:

• Stump appendicitis occurs when residual appendiceal tissue (>5mm retained stump) becomes inflamed, presenting identically to acute appendicitis with right lower quadrant pain 3, 4
• Adhesive small bowel obstruction is the most common cause of bowel obstruction in patients with prior abdominal surgery, accounting for 55-75% of small bowel obstructions, and a history of prior surgery has 85% sensitivity and 78% specificity for predicting adhesive obstruction 5

CT with IV contrast will simultaneously evaluate both possibilities and identify alternative diagnoses in 23-45% of cases presenting with right-sided abdominal pain 1, 2

Critical Physical Examination Findings to Document Now

Before imaging, assess for:

• Peritoneal signs: rebound tenderness, involuntary guarding, or rigidity in the right lower quadrant—these indicate peritoneal inflammation requiring urgent surgical evaluation 5, 1
• Bowel sounds: absent or high-pitched tinkling sounds suggest obstruction 5
• Distension: visible abdominal distension with tympany suggests bowel obstruction 5
• Vital signs: fever >38°C and tachycardia increase likelihood of complicated pathology, though fever is absent in ~50% of appendicitis cases 1

Laboratory Tests to Order Immediately

• Complete blood count with differential: leukocytosis >14,000/μL suggests inflammation, though normal WBC does not exclude stump appendicitis or early obstruction 5, 1
• C-reactive protein: elevated CRP >50 mg/L increases diagnostic probability, but CRP <0.4 mg/dL does not rule out early appendicitis 2
• Beta-hCG if patient is female of reproductive age—mandatory before imaging to exclude ectopic pregnancy 1, 2

The Stump Appendicitis Diagnostic Challenge

Stump appendicitis is rare but dangerous, with these key features:

• Presents with identical symptoms to acute appendicitis: right lower quadrant pain (59% of cases), periumbilical pain radiating to RLQ (14%), nausea, and vomiting 3
• Diagnosis is almost always delayed because clinicians incorrectly assume prior appendectomy excludes appendiceal pathology 3, 4
• CT scan is the diagnostic tool of choice, identifying the inflamed residual appendiceal stump and surrounding inflammation 3, 4
• Perforation risk is higher due to diagnostic delay—surgeons must maintain high clinical suspicion 4

CT Protocol Specifications

Order the study as follows:

• CT abdomen and pelvis with IV contrast only—do not delay for oral contrast, as IV contrast alone provides equivalent diagnostic accuracy without treatment delays 1, 2
• Whole abdomen/pelvis coverage is mandatory—limiting CT to pelvis only misses 7% of surgical pathology located in the abdomen 2
• IV contrast enables detection of mucosal hyperenhancement, wall thickening, periappendiceal inflammation, and abscess formation 1, 6

Management Algorithm Based on CT Findings

If CT Shows Stump Appendicitis (Inflamed Residual Appendix >8.2mm)

• Immediate surgical consultation for completion appendectomy—probability of true appendicitis exceeds 90% with these findings 1, 2
• Start broad-spectrum antibiotics covering gram-negative and anaerobic organisms 1
• If perforated with abscess >3cm, consider percutaneous drainage followed by interval appendectomy 2

If CT Shows Adhesive Small Bowel Obstruction

• Admit for surgical evaluation and initiate conservative management: NPO status, nasogastric decompression if vomiting, IV fluid resuscitation 5
• Serial abdominal examinations every 6-12 hours to monitor for peritoneal signs indicating strangulation or perforation 5, 1
• Surgical intervention is indicated if: peritoneal signs develop, clinical deterioration occurs, or obstruction fails to resolve within 24-48 hours 5

If CT Shows Alternative Diagnosis

• Right colonic diverticulitis (8% of RLQ pain cases): treat with antibiotics per World Society of Emergency Surgery classification 1, 2
• Ureteral stone (19% of right-sided inflammatory presentations post-surgery): urology consultation for stone management 2
• Gynecologic pathology (21.6% of alternative diagnoses): ovarian torsion, ruptured cyst, or pelvic inflammatory disease require gynecology consultation 1

If CT is Negative but Clinical Suspicion Remains High

• Admit for 24-hour observation with serial abdominal examinations and repeat laboratory tests 1
• Early appendicitis or stump appendicitis may lack classic CT findings—sensitivity ranges from 85.7-100%, meaning up to 14% of cases may be missed on initial imaging 1, 2
• If symptoms worsen or peritoneal signs develop, proceed to diagnostic laparoscopy 1

Common Pitfalls to Avoid

• Never assume prior appendectomy excludes appendiceal pathology—stump appendicitis is rare but well-documented and potentially life-threatening 3, 4, 7, 8
• Do not rely on absence of fever or normal WBC to exclude serious pathology—fever is absent in 50% of appendicitis cases, and inflammatory markers may be normal in early disease 1, 2
• Do not discharge without establishing 24-hour follow-up and providing explicit return precautions: worsening pain, fever, vomiting, or inability to tolerate oral intake 1
• Do not order plain abdominal radiography—it has minimal diagnostic value for evaluating RLQ pain 1

Special Consideration: Recurrent vs. Duplicated Appendix

In extremely rare cases, patients may have a duplicated appendix or full-blown recurrent appendicitis of vermiform appendix after prior appendectomy, distinct from stump appendicitis 7. CT will identify this anatomic variant, and surgical management remains appendectomy 7.