TH7.3 Is CT a valid tool for diagnosing acute appendicitis in patients aged 40 or older?

To establish whether computerised tomography abdomen and pelvis (CTAP) with contrast is a necessary tool in the diagnosis of acute appendicitis in those aged 40 years or older compared to clinical assessment alone. The study was performed in a district general hospital in England. A retrospective analysis included 314 patients aged 40 years or older who presented between 3rd October 2020 and 31st October 2021 and received a CTAP with contrast where the request queried appendicitis. An Alvarado score was calculated for each patient as a measure of clinical likelihood of appendicitis based on documentation from their initial assessment by a General Surgeon. CTAP demonstrated evidence of acute appendicitis in 46.1% of patients. CTAP diagnosed alternative pathologies in 41.1% of patients. These included diverticulitis (10.5%), gynaecological pathology (4.5%), urological pathology (3.2%), malignancy (2.9%) and others (19.4%). 11.8% demonstrated no cause for symptoms. Furthermore, those with an Alvarado score of 9 or more, 94.9% had a CTAP reporting appendicitis. With scores of 3–8, only 49.4% had a CT finding of appendicitis and this dropped to 5.0% with scores of 0–2. This study supports using CTAP to aid in diagnosing appendicitis in patients aged 40 years or older with Alvarado scores of 8 or less. However, patients scoring 9 or more had a 94.4% positive finding of acute appendicitis on CTAP, thus potentially negating the need for a CTAP scan pre-operatively. Alvarado scores of 2 or less suggest an alternative diagnosis is more likely, however CTAP may still be a valid investigation.