Appendicitis?

CTUSWSES Jerusalem 2020

Right lower quadrant pain; the surgeon is deciding whether to book the OR tonight.

Answer the surgeon

Operative vs non-operative management. An organized abscess may be treated with antibiotics ± image-guided drainage, while laparoscopy remains appropriate where advanced expertise is available.

Your answer must state:

Acute appendicitis: yes, no, or equivocal
Perforated or not — extraluminal gas, abscess or phlegmon, focal wall defect
Abscess size and location if present (drainable?)
Appendicolith present or absent — raises failure risk of non-operative management
Inflammation at the appendiceal base / cecum — affects stump closure

Key and direct findings

1.Dilated appendix with wall thickening and hyperenhancementCT
Outer diameter >6 mm with mural thickening and hyperenhancing wall on CT; 6–10 mm is borderline — weigh the secondary signs.
Pitfall: A gas-filled appendix >6 mm with no wall thickening or fat stranding is usually normal — do not call appendicitis on diameter alone.
2.Periappendiceal fat strandingCT
Inflamed fat around the appendix is the most reliable secondary sign on CT.
Pitfall: Early appendicitis can show a dilated appendix with minimal stranding — absence of stranding does not exclude it.
3.Non-compressible appendix >6 mm on USUS
Blind-ending, non-compressible tubular structure >6 mm outer diameter with hyperemia and echogenic inflamed periappendiceal fat.
Pitfall: A perforated appendix can decompress and measure normal — look for the periappendiceal changes.
4.Perforation signsCT
Extraluminal gas, periappendiceal abscess or phlegmon, focal defect in the enhancing wall, or an extraluminal appendicolith.

Supportive signs & checks

1.AppendicolithCT
Calcified intraluminal stone; note it explicitly — it predicts failure of antibiotic-only management.
2.Trace the full length to the tip
Tip appendicitis spares the base; a normal proximal appendix does not clear the study.
Pitfall: The commonest false negative on both CT and US is not following the appendix to its tip.
3.Check the mimics before signing
Cecal diverticulitis, mesenteric adenitis, Crohn's terminal ileitis, right-sided colitis, and gynecologic causes in women.

Wet-read snippets

Fill the blanks, then copy into your preliminary report.

Positive

Acute appendicitis: appendix ___ mm with periappendiceal fat stranding; no extraluminal gas or organized collection to suggest perforation. Appendicolith: ___.

Negative

Normal appendix identified (___ mm, compressible/gas-filled, no periappendiceal inflammation). No evidence of acute appendicitis; no alternative inflammatory cause identified.

Equivocal

Borderline appendix (___ mm) without periappendiceal inflammation — equivocal for early appendicitis. Suggest clinical correlation and reassessment or short-interval follow-up imaging.

Sources

WSES Jerusalem guidelines for acute appendicitis (2020 update) — Di Saverio S et al. World J Emerg Surg (2020)
ACR Appropriateness Criteria: Right Lower Quadrant Pain — American College of Radiology (2022)

Content review: Content pending clinical review · 2026-07-15

Educational reference for trained clinicians. Verify every result against the cited original guideline before use. Not a substitute for clinical judgment or medical advice.