Perforated mucinous diverticulitis of the appendix: a case report

Acute right lower quadrant (RLQ) abdominal pain typically raises the suspicion of appendicitis and must be ruled out, as the treatment is primarily surgical. Other differentials, many of which are medically treated, ought to also be considered. Right sided diverticulitis, although uncommon, often mimics appendicitis due to its inflammatory nature and its location of pain. A 37-year-old woman with a history of recurrent right-sided diverticulitis presented with rapidly escalating RLQ pain. While appendicitis was a prime suspect, additional imaging was refused due to radiation concerns, hence clinical judgement had to be aptly applied. Facing diagnostic ambiguity, Hickam's dictum (seeking the most probable cause) pointed towards appendicitis, while Ockham's razor (favouring the simplest explanation) supported recurrent right sided diverticulitis. This uncertainty necessitated a definitive approach, weighing up the risks and benefits of medical vs surgical treatment for an unconfirmed pathology. To resolve the uncertainty, a diagnostic laparoscopy was performed. Contrary to expectations, it revealed a perforated diverticulum of the appendix with a mucinous tip and free-floating mucin, making both leading differentials, that is, right sided diverticulitis and appendicitis, correct. We explore the diagnostic reasoning used in the case, including the anticipated management strategies and outcomes, if other differentials were encountered. This case aims to support clinicians in pursuing further investigations, or need be, a diagnostic laparoscopy, in order to prioritise patient safety, if clinical concern is present.