What is the appropriate next step in management for a patient with suspected acute appendicitis and a palpable mass in the right iliac fossa?

Management of Suspected Complicated Appendicitis with Right Iliac Fossa Mass

CT abdomen with contrast should be obtained as the next step in management for this patient with a palpable right iliac fossa mass and clinical signs of complicated appendicitis. 1

Clinical Context and Rationale

This patient presents with classic features suggesting complicated appendicitis rather than uncomplicated disease:

• Palpable mass in the right iliac fossa (suggesting phlegmon or abscess formation) 1
• Peritoneal signs (rebound tenderness) 2
• Progressive symptoms over 3 hours 2

The presence of a palpable mass fundamentally changes the management approach from simple appendicitis, making imaging essential before any surgical intervention. 1, 3

Diagnostic Imaging Algorithm

First-line imaging should be CT abdomen with IV contrast, which provides:

• High diagnostic accuracy with sensitivity 85.7-100% and specificity 94.8-100% 1
• Critical information about the presence of abscess, phlegmon, or appendicolith 2
• Guidance for determining whether immediate surgery versus initial non-operative management is appropriate 3

While ultrasound is recommended as first-line for uncomplicated appendicitis, CT is superior when a mass is palpable because:

• It better characterizes the extent of complicated disease 1
• Ultrasound has limited accuracy in obese patients and may miss abscess formation 1
• CT findings directly influence the treatment strategy (immediate surgery vs. percutaneous drainage + antibiotics) 4, 3

Why Not the Other Options

Exploratory laparotomy (Option B) is premature without imaging because:

• CT findings of abscess or large phlegmon may indicate that initial non-operative management (percutaneous drainage + antibiotics followed by interval appendectomy) has better outcomes than immediate surgery 3
• Urgent appendectomy for complicated appendicitis with abscess has higher complication rates compared to elective surgery after initial antibiotic therapy 3
• The patient is hemodynamically stable, allowing time for diagnostic imaging 5

Biopsy (Option C) has no role in acute appendicitis management 5

Discharge (Option D) is inappropriate given clear signs of acute surgical pathology with peritoneal irritation 2, 4

Management Algorithm Based on CT Findings

Once CT is obtained, management depends on findings:

If large abscess (>3-5 cm) or phlegmon:

• Initial treatment with IV antibiotics and percutaneous drainage 4, 3
• Interval appendectomy after 6-8 weeks 3
• This approach reduces postoperative complications compared to urgent surgery 3

If perforated appendicitis without organized abscess:

• Proceed to urgent laparoscopic appendectomy 5
• Laparoscopic approach preferred over open surgery for better outcomes 5, 6

If appendicolith present on CT:

• Surgical management strongly recommended as antibiotics-first approach has ~40% failure rate 2

Critical Pitfalls to Avoid

• Do not proceed directly to surgery without imaging when a mass is palpable - this may lead to unnecessary complications if an abscess could be drained percutaneously first 3
• Do not use ultrasound as the sole imaging modality when complicated appendicitis is suspected clinically - CT provides superior characterization 1
• Do not delay imaging in stable patients - the 2020 WSES guidelines emphasize that cross-sectional imaging is recommended before surgery when complications are suspected 5