A Study to Evaluate the Combined Use of Alvarado Score and Imaging for Diagnosis of Acute Appendicitis.

Acute appendicitis is one of the most common abdominal emergencies encountered in surgical practice. The diagnosis of acute appendicitis is an enigmatic challenge. Several studies have reported a variable diagnostic accuracy with a negative appendicectomy rate varying from 3% up to 20% using combined diagnostic modalities or using Alvarado score alone. The present study was carried out to evaluate the diagnostic efficacy of combined use of Alvarado score and imaging modalities (USG and / or CECT abdomen) for preoperative diagnosis of acute appendicitis.METHODSThe present study was a prospective observational study carried out in a tertiary hospital of a metropolitan city. The study period extended over two years, from January 2016 till December 2018. The study included 118 adults who presented with clinical features of acute appendicitis. Alvarado scoring system based mainly on clinical features was applied and graded. Compression USG was performed on all patients. CECT of abdomen was done in 30 patients having inconclusive results on USG. Appendicectomy was performed on all the patients after the Alvarado scoring and imaging. The histopathological findings of the surgical specimens were noted to confirm the pathological diagnosis. The sensitivity, specificity, PPV, NPV and accuracy of the diagnostic methods were calculated.RESULTSOut of 118 appendicectomies, 104 were found to be positive on histopathology, with an overall 11.86% negative appendicectomy rate. Combined use of imaging with a high Alvarado score (7-10) had a sensitivity of 95.74%, specificity of 100%, accuracy of 95.8%. Combined use of imaging with a low Alvarado score (3-6) had a sensitivity of 89.47%, specificity of 53.8%, accuracy of 82.85%. Alvarado score alone had a sensitivity of 45.19%, specificity of 92.85% and accuracy of 50.8%. USG alone showed a sensitivity of 71.15%, specificity of 71.42% and accuracy of 71.18%. CECT alone had a sensitivity of 88%, specificity of 60% and accuracy of 83.3%.CONCLUSIONSImaging modalities have a valuable role in terms of diagnostic accuracy particularly in cases having low Alvarado score. CECT though expensive is preferable to USG. However, the combined methodology of Alvarado scoring, and imaging is a rational approach for accurate diagnosis preventing surgical complications and minimizing negative appendicectomy rate.