Diagnostic Approach for Right Iliac Fossa Pain

Initial Diagnostic Approach

The American College of Radiology recommends Point-of-care Ultrasound (POCUS) as the most appropriate first-line diagnostic tool in adults with suspected appendicitis when imaging is indicated based on clinical assessment 1, 2
Ultrasound has satisfactory sensitivity and specificity in diagnosing acute appendicitis, allowing for swift decision-making 1
In obese patients, the diagnostic performance of US may be limited, with higher false diagnosis rates compared to non-obese patients (46.2% vs 38.5% in females) 3, 4

The World Journal of Emergency Surgery suggests that the first step in the diagnostic algorithm should be Ultrasound evaluation 5
The graded compression technique should be used to displace intervening organs and simulate clinical deep abdominal palpation 4
If US is inconclusive or negative, a contrast-enhanced low-dose CT scan should be performed, which provides diagnostic accuracy not inferior to standard CT while reducing radiation exposure 1, 2
CT has high sensitivity (85.7-100%) and specificity (94.8-100%) for diagnosing appendicitis 6
If imaging remains inconclusive but clinical suspicion is high, diagnostic laparoscopy is recommended to establish/exclude the diagnosis of acute appendicitis or alternative diagnoses 1, 2

Obesity is a significant limiting factor for US accuracy, with higher false diagnosis rates in obese patients 3, 4
Diagnostic laparoscopy has both diagnostic and therapeutic value, allowing for immediate intervention if appendicitis is confirmed 5

The American College of Radiology recommends contrast-enhanced CT abdomen and pelvis as a diagnostic imaging modality for suspected appendicitis, with high diagnostic yield: sensitivity 85.7-100% and specificity 94.8-100% 7, 8
CT has a high diagnostic accuracy, with a negative appendectomy rate of 1.7-7.7%, compared to historical rates of 14.7% without imaging 7, 8
Low-dose contrast-enhanced CT provides diagnostic accuracy not inferior to standard CT while reducing radiation exposure 7

Without preoperative imaging, the negative appendectomy rate is 16.7% with clinical evaluation alone versus 8.7% with CT 8
Preoperative imaging, such as CT, can help reduce the negative appendectomy rate and associated long-term morbidity 7, 8

For obese patients with suspected appendicitis, CT with IV contrast achieves sensitivities of 90-100% and specificities of 94.8-100% 7