What is the most appropriate management for a patient with increasing right lower quadrant pain and rebound tenderness, suspected of having acute appendicitis?

Management of Suspected Acute Appendicitis with Classic Presentation

For a patient presenting with increasing right lower quadrant pain and rebound tenderness, CT abdomen and pelvis with IV contrast is the most appropriate next step, not immediate appendectomy. 1, 2

Rationale for Imaging Before Surgery

The negative appendectomy rate without preoperative imaging is unacceptably high at 14.7-25%, which exposes patients to unnecessary surgical morbidity and mortality. 1 With preoperative CT, this rate drops dramatically to 1.7-7.7%, representing a critical improvement in patient outcomes. 1

Diagnostic Performance of CT

• CT abdomen and pelvis with IV contrast demonstrates sensitivity of 85.7-100% and specificity of 94.8-100% for acute appendicitis. 1
• CT without enteral contrast (oral or rectal) achieves sensitivity of 90-100% and specificity of 94.8-100%, avoiding delays associated with oral contrast administration. 1
• CT identifies alternative diagnoses in 23.2-45.3% of patients presenting with right lower quadrant pain and classic symptoms, fundamentally changing management in a substantial proportion of cases. 1

Critical Value of Preoperative Imaging

Even with classic clinical presentation including right lower quadrant pain and rebound tenderness, imaging is essential because:

• The classic presentation (periumbilical pain migrating to right lower quadrant, anorexia, nausea/vomiting, fever) is present in only approximately 50% of appendicitis cases. 1, 3
• Fever is absent in approximately 50% of confirmed appendicitis cases, making clinical diagnosis unreliable. 2, 4
• Rebound tenderness alone, even without fever or inflammatory markers, can represent appendicitis but requires imaging confirmation. 4

Alternative Diagnoses Detected by CT

CT frequently identifies other surgical and non-surgical conditions requiring different management: 1

• Right colonic diverticulitis (8% of cases) 1
• Ureteral stones 1
• Intestinal obstruction (3% of cases) 1
• Gynecologic pathology (21.6% of alternative diagnoses) 1
• Gastrointestinal conditions (46.0% of alternative diagnoses) 1

When to Proceed Directly to Surgery

Direct surgical consultation without imaging may be considered only in patients with:

• High clinical suspicion (Alvarado Score ≥7) AND
• Hemodynamic instability or peritonitis suggesting perforation 5

However, even in high-risk patients who are hemodynamically stable, CT provides critical information about perforation status, abscess formation, and surgical planning. 1

CT Findings That Guide Management

Specific CT findings stratify surgical urgency and approach: 6

• Appendiceal diameter ≥7 mm confirms appendicitis 6
• Appendicolith presence predicts 40% failure rate with antibiotic-first approach 6
• Appendiceal diameter >13 mm with mass effect indicates complicated appendicitis requiring surgery 6
• Focal wall defect has 98.8% specificity for perforation 1

Common Pitfalls to Avoid

Do not rely on absence of fever to exclude appendicitis or delay imaging. 2 Fever is present in only 50% of cases, and waiting for fever development risks perforation. 1, 3

Do not proceed to appendectomy based solely on clinical examination, even with classic findings. 1 The 14.7-25% negative appendectomy rate without imaging represents preventable surgical morbidity. 1

Do not order CT with oral contrast, as this delays diagnosis and treatment without improving diagnostic accuracy. 1, 3 CT with IV contrast alone is preferred. 1

Recommended Imaging Protocol

Order CT abdomen and pelvis with IV contrast without enteral contrast for: 1

• Rapid acquisition (no waiting for oral contrast transit)
• Excellent sensitivity and specificity (90-100% and 94.8-100% respectively)
• Detection of alternative diagnoses
• Assessment of perforation and abscess formation

The optimal CT technique uses: 1

• Maximal outer diameter cutoff of 8.2 mm (sensitivity 88.8%, specificity 93.4%)
• Evaluation for periappendiceal fat stranding
• Assessment for intraluminal gas absence
• Detection of appendicoliths