Other Differential Diagnoses of Acute Abdomen Assessed with POCUS

This chapter addresses important non-classical causes of acute abdomen that can be rapidly evaluated using point-of-care ultrasound (POCUS). It focuses on high-impact and time-sensitive conditions frequently encountered in emergency and surgical settings, including ruptured ectopic pregnancy, nephrolithiasis and other renal causes, acute pyelonephritis, and mesenteric ischemia. The chapter integrates clinical context, physiological considerations, ultrasound techniques, key sonographic findings, diagnostic performance, and limitations of POCUS, emphasizing its role in early recognition, risk stratification, and decision-making when advanced imaging is unavailable or delayed.