Radiology · Year 4 · from Radiology

Case 3: Acute Appendicitis with Perforation

Patient Demographics

  • Age: 34 years
  • Sex: Male

Chief Complaint

Right lower quadrant pain for 3 days, worsening

Presenting Symptoms

The patient reports abdominal pain that began 3 days ago as vague periumbilical discomfort. Over the first 24 hours, the pain migrated to the right lower quadrant and became sharper. He initially thought it was "something he ate" and delayed seeking care. For the past 24 hours, the pain has become more diffuse and severe. He has had low-grade fevers, anorexia, and one episode of diarrhea. He reports temporary improvement in pain yesterday followed by significant worsening - concerning for perforation.

Physical Exam Findings

  • Vital Signs: BP 108/68 mmHg, HR 112 bpm, RR 22/min, Temp 38.9C
  • General: Ill-appearing, lying very still
  • Abdomen: Diffuse tenderness, most pronounced in right lower quadrant, involuntary guarding, rebound tenderness, Rovsing sign positive, psoas sign positive
  • Laboratory: WBC 18,400/uL with 92% neutrophils, CRP 186 mg/L

Imaging Findings and Interpretation

CT Abdomen/Pelvis with IV Contrast:

  • Appendix: Dilated, thick-walled appendix measuring 14 mm in diameter
  • Perforation: Focal defect in the appendiceal wall with adjacent extraluminal gas bubbles
  • Appendicolith: 8 mm calcified appendicolith present within the proximal appendix
  • Abscess: 4.2 x 3.8 cm rim-enhancing fluid collection adjacent to the appendiceal tip in the right lower quadrant
  • Periappendiceal Changes: Extensive fat stranding and inflammatory changes in the right lower quadrant mesentery
  • Reactive Changes: Thickening of the terminal ileum and cecal wall due to adjacent inflammation
  • Free Fluid: Moderate amount of free fluid in the pelvis
  • No Free Air: No large volume pneumoperitoneum

Staging of Appendicitis: Based on CT findings, this represents complicated appendicitis with perforation and abscess formation (Grade 5 per the CT-based grading system).

Diagnosis

Perforated appendicitis with periappendiceal abscess

Management

  1. IV fluid resuscitation addressing sepsis (crystalloid bolus)
  2. Broad-spectrum IV antibiotics: Piperacillin-tazobactam
  3. Two management options discussed:

Option A - Immediate Surgery:

  • Laparoscopic appendectomy with peritoneal lavage
  • Abscess drainage at time of surgery
  • Higher risk of complications (wound infection, conversion to open)

Option B - Interval Appendectomy Approach (Selected):

  • CT-guided percutaneous drainage of abscess by interventional radiology
  • IV antibiotics for 7-10 days followed by oral antibiotics
  • Interval appendectomy in 6-8 weeks after inflammation resolves
  • Colonoscopy recommended before interval surgery (age-appropriate, rule out occult malignancy)
  1. Patient underwent successful percutaneous drainage with 8 French catheter
  2. Clinical improvement over 5 days, abscess cavity collapsed on follow-up imaging
  3. Interval laparoscopic appendectomy performed 8 weeks later without complications

Radiological Image

Image Description: CT scan demonstrating acute appendicitis with perforation. The dilated, thick-walled appendix is visible with an adjacent rim-enhancing abscess cavity. Periappendiceal fat stranding and an appendicolith are present.

Source: Wikimedia Commons - "CT scan of appendicitis" URL: https://commons.wikimedia.org/wiki/File:Appendicitis_CT.jpg License: Creative Commons Attribution-Share Alike 3.0 Unported

Learning Points

  1. Transition Point Identification: In small bowel obstruction, identifying the transition point on CT is crucial for determining the cause and planning intervention. Adhesions are the most common cause in patients with prior abdominal surgery.
  1. Sonographic Murphy Sign: The combination of gallstones + gallbladder wall thickening (>3 mm) + pericholecystic fluid + positive sonographic Murphy sign is highly specific for acute cholecystitis and usually sufficient for diagnosis without additional imaging.
  1. Complicated vs. Uncomplicated Appendicitis: CT can distinguish uncomplicated appendicitis (amenable to surgery or antibiotics alone in select cases) from complicated appendicitis with perforation, abscess, or phlegmon, which may benefit from initial drainage and interval appendectomy.
  1. Signs of Strangulation: In bowel obstruction, CT findings suggesting strangulation include bowel wall thickening, decreased wall enhancement, mesenteric haziness, pneumatosis intestinalis, and portomesenteric venous gas. These findings mandate urgent surgical intervention.

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