Historically appendiceal diverticulitis has been thought to be a rare diagnosis. However a study from 2015 which retrospectively reviewed the pathological specimens in 451 patients that had appendectomies found that 9.7% were actually appendiceal diverticulitis .
The presentation is very similar to acute appendicitis, and occasionally an acute appendiceal diverticulitis will be the cause of right iliac fossa pain in an acutely unwell patient.
Appendiceal diverticula are false diverticula in that they represent focal protrusions of the mucosa and submucosa through a muscle defect; this is histologically identical to colonic diverticula.
In appendiceal diverticulitis there is acute inflammation of the diverticulum with very little or completely absent inflammation of the appendiceal wall (cf. appendicitis) .
An acutely inflamed diverticulum arising from the appendix will be seen in uncomplicated cases. However when there is an abscess it can be impossible to differentiate an appendiceal diverticulitis from an appendicitis.
Compared to acute appendicitis, the following features are more likely to be seen:
- periappendiceal fluid
- periappendiceal fat stranding
- larger caliber of the appendix
Compared to acute appendicitis, the following features are less likely to be seen:
- loculated intraluminal fluid
- appendiceal abscess
History and etymology
The first case description of diverticulitis of the appendix was published in 1893 by British physician Theophilus Nicholas Kelynack .