Effervescence sign - a new sonographic sign of gastric outlet obstruction: A case report and literature review of superior mesenteric artery syndrome.

Introduction: Superior mesenteric artery syndrome is a rare pathological cause of gastric outlet obstruction. Traditionally, computer tomography and magnetic resonance imaging scans have been diagnostic investigations of choice. However, due to vague symptoms of gastric outlet obstruction, there is a delay to diagnosis of superior mesenteric artery syndrome in acute setting. This case describes the use of point-of-care ultrasound scan for diagnosis of superior mesenteric artery syndrome in the emergency department.

Case presentation: We present a case of a 25-year-old woman presenting to the emergency department with signs and symptoms of gastric outlet obstruction caused by superior mesenteric artery syndrome. Point-of-care ultrasound scan demonstrated a fluid-filled stomach with continuous bubbling of air (effervescence sign) and a loop of duodenum compressed between the aorta and the superior mesenteric artery, suggesting a diagnosis of superior mesenteric artery syndrome. Subsequent computed tomography scan confirmed the point-of-care ultrasound scan findings.

Discussion: Ultrasound has been described as a reliable diagnostic modality to diagnose the radiological signs of superior mesenteric artery syndrome. Our newly identified sign of continuous bubbling of air (effervescence sign) on point-of-care ultrasound scan, due to fermentation of stomach contents, and its ability to identify diagnostic features of superior mesenteric artery syndrome demonstrate its utility as a diagnostic tool in the emergency department reducing time delays and costs associated with traditional diagnostic modalities. Point-of-care ultrasound scan can aid in the diagnosis of superior mesenteric artery syndrome in the emergency department.

Conclusion: Increased awareness of the capabilities of using point-of-care ultrasound scan in the emergency department and our newly identified 'effervescence sign' will enable timely and low-cost diagnoses, while closing current literature gap and establishing point-of-care ultrasound scan as a feasible diagnostic tool for gastric outlet obstruction secondary to superior mesenteric artery syndrome.