In a 43-year-old man with right lower quadrant abdominal pain and CT showing a mildly enlarged retrocecal appendix (8–9 mm) without periappendiceal fat stranding, fluid collection, or appendicolith, and small reactive mesenteric lymph nodes, what is the appropriate management?

Management of Mildly Prominent Appendix Without Inflammatory Changes

In this 43-year-old man with right lower quadrant pain and a mildly prominent appendix (8-9 mm) without periappendiceal fat stranding, appendicolith, or fluid collection, conservative management with close clinical observation and outpatient follow-up is appropriate, as the CT findings do not meet diagnostic criteria for acute appendicitis. 1

Diagnostic Assessment

The CT findings in this case are equivocal and do not confirm acute appendicitis for the following reasons:

• Appendiceal diameter is borderline: The optimal cutoff for diagnosing appendicitis is >8.2 mm outer diameter (sensitivity 88.8%, specificity 93.4%), and this patient's appendix measures 8-9 mm, which is at the threshold 1

• Absence of critical inflammatory signs: The most diagnostically valuable CT findings for appendicitis are missing in this case:

  • No periappendiceal fat stranding (present in 87-100% of appendicitis cases, with 80-87% specificity) 2, 3
  • No appendiceal wall thickening (66% sensitivity, 96% specificity) 3
  • No appendiceal wall enhancement defects 1
  • No appendicolith (44-55% sensitivity when present, but 100% specificity and predicts perforation with OR 2.47-2.67) 1, 4, 2
  • No periappendiceal fluid 1

• The combination of findings matters most: An enlarged appendix with periappendiceal fat stranding occurs in 93% of appendicitis cases 2. When two or more CT signs are present, the odds ratio of appendicitis is 6.8 (95% CI: 3.0-15.5) 1. This patient has only borderline appendiceal enlargement without supporting inflammatory findings.

Recommended Management Strategy

Immediate Actions

• Discharge with safety-net instructions rather than surgical consultation, given the absence of inflammatory changes 1, 5

• Provide clear return precautions: Instruct the patient to return immediately if he develops:

  • Worsening or persistent right lower quadrant pain
  • Fever (temperature >38°C/100.4°F)
  • Nausea, vomiting, or inability to tolerate oral intake
  • Development of peritoneal signs (guarding, rebound tenderness, rigidity) 5

• Consider alternative diagnoses: The small reactive mesenteric lymph nodes (4 mm) suggest possible mesenteric adenitis or a self-limited viral process 1

Follow-Up Plan

• Clinical reassessment within 24-48 hours either in person or by telephone to evaluate symptom progression 5

• Repeat imaging only if symptoms worsen or persist: If pain intensifies or new symptoms develop, repeat CT with IV contrast (without oral contrast) has 96% sensitivity and 93% specificity for appendicitis 1

• No empiric antibiotics are indicated in the absence of confirmed appendicitis, as antibiotic therapy is reserved for proven uncomplicated appendicitis (70% success rate) or as adjunct to surgery 4, 6

Critical Clinical Pitfalls to Avoid

• Do not operate based on borderline appendiceal diameter alone: The frequently referenced 6 mm cutoff has poor specificity (59.6%) and would lead to unnecessary appendectomies 1. The optimal cutoff of 8.2 mm has much better diagnostic accuracy 1

• Do not dismiss the absence of fat stranding: Fat stranding is present in 87-100% of appendicitis cases and has 74-80% specificity 2, 3. Its absence in the setting of borderline appendiceal enlargement makes acute appendicitis unlikely 7

• Recognize that retrocecal position does not change diagnostic criteria: While the appendix is retrocecal in this patient, the same CT diagnostic criteria apply, and the absence of inflammatory changes remains the key finding 1

• Avoid over-reliance on clinical scoring systems alone: The Alvarado score and similar tools are useful for risk stratification but should not replace imaging interpretation in equivocal cases 5

When to Escalate to Surgery

Immediate surgical consultation is mandatory if 1, 4, 6:

• Fat stranding develops on repeat imaging (indicates acute inflammation) 7, 2, 3
• Appendicolith appears (predicts perforation and treatment failure with antibiotics) 1, 4
• Appendiceal diameter increases to >13 mm (associated with 40% antibiotic failure rate) 4
• Signs of perforation emerge (extraluminal air, abscess, phlegmon, wall defect) 1, 6
• Clinical deterioration occurs with peritoneal signs 5