ReviewHow to diagnose an acutely inflamed appendix; a systematic review of the latest evidence

•Acute appendicitis is the most common condition that presents to hospitals with an acute abdomen.•A delay or mis-diagnosis of appendicitis can result in severe complications.•Raised Alvarado scores and laboratory markers all contribute to the suspicion of appendicitis.•The use of USS-CT pathways or even USS-MRI pathways increases diagnostic certainty without always having to expose unclear cases to radiation.•The alternative use of repeat USS may reach a sensitivity of 100%.

Acute appendicitis is the most common condition that presents with an acute abdomen needing emergency surgery. Despite this common presentation, correctly diagnosing appendicitis remains a challenge as clinical signs or positive blood results can be absent in 55% of the patients.The reported proportion of missed diagnoses of appendicitis ranges between 20% and 40%. A delay or mis-diagnosis of appendicitis can result in severe complications such as perforation, abscess formation, sepsis, and intra-abdominal adhesions.Literature has shown that patients who had a negative appendectomy suffer post-op complications and infections secondary to hospital stays; there have even been reported cases of fatality.It is therefore crucial that timely and accurate diagnosis of appendicitis is achieved to avoid complications of both non-operating as well as unnecessary surgical intervention.The aim of this review is to systematically report and analyse the latest evidence on the different approaches used in diagnosing appendicitis. We include discussions of clinical scoring systems, laboratory tests, latest innovative bio-markers and radiological imaging.