IS Case 233: cute appendicitis with appendicolith
Imaging Sciences URMC 2008
Publication Date: 2009-05-22
The presence of a calcification in the right lower quadrant with the appropriate clinical history is very concerning for acute appendicitis. In certain studies, abdominal pain with an appendicolith has a positive predictive value of 90% for acute appendicitis. Approximately 50% of patients who present with an appendicolith have appendicitis complicated with perforation or abscess.
Only 15% of patients with acute appendicitis have a radiographically visible appendicolith. One-third of removed appendices have an appendicolith. The location is usually in the right lower quadrant of the abdomen, however, may occur in the pelvis (as in this case), retrocecal, or in the left upper quadrant.
The differential diagnosis includes: phleboliths which usually contain a central lucency, calcified lymph nodes which usually are "popcorn" calcifications, calcification from a dermoid tumor or prior ovarian torsion, ureteral/bladder calcifications, bone islands, and fibroids in older patients.
Plain film signs of appendicitis include:
- Abnormal bowel gas pattern such as a localized ileus or bowel loop displacement by a fluid filled mass (the inflamed appendix/cecum).
- Abnormal cecum and ascending colon related to local inflammation and edema.
- A cecal air-fluid level may be present.
- Obliteration of normal fat planes due to inflammation and edema. Obscuration of the right properitoneal flank stripe, psoas muscle, or obturator muscle is possible.
- Free air is concerning for perforation.
- Johnson C, Schmit G. Mayo Clinic Gastrointestinal Imaging Review. Mayo Clinic Scientific Press, 2005.
- Messmer JM. Acute appendicitis with an appendicolith. Gastrointestinal Learning File - ACR. MedPix: Medical Image Database, Atlas, and Teaching File: Topic 1589.