Case 9:  Appendicitis

The appendix is filled with fluid. It measures greater than 6 mm.  There is enhancement of the mucosa.  There is stranding in the surrounding fat.  There is thickening at the base of the cecum.  Also, there is thickening of the adjacent peritoneum. 

The appendix can lie in any direction.  When it is situated laterally it will lay adjacent to the lateral conal fascia (the fascia along the postero-lateral abdominal wall below the kidneys).  When this is thickened it clues you into inflammation somewhere adjacent to the abdominal wall; in this case appendicitis.  Normally, this fascia is razor thin and nearly imperceptible.

In this case, as in the previous cases, the appendix originates several centimeters inferior to the ileocecal valve, opposite the ascending colon.  See schematic.  It courses superiorly adjacent to the ascending colon to the level of the kidney.  Then it then loops laterally and inferiorly.  This is very common place to see a large appendiceal phlegmon.  If you see a large focus of soft tissue inflammation in this area and cannot find the appendix, the diagnosis is appendiceal phlegmon or abscess.

Take home points:

• Thickening of the lateral conal fascia suggests inflammation adjacent to the abdominal wall.
• Inflammation along the lateral side of the cecum and ascending colon suggests appendicitis, colitis, or cecal diverticulitis.