Upside down stomach sign | Radiology Signs

Upside down stomach is caused by a severe form of paraesophageal hiatal hernia characterized by organoaxial gastric volvulus, where the entire stomach herniates into the thoracic cavity through the esophageal hiatus. This malrotation leads to displacement of the greater curvature superior to the lesser curvature. It is associated with clinical conditions such as postprandial chest discomfort, dysphagia, vomiting, anemia from chronic mucosal bleeding, and may present acutely with complications like strangulation, obstruction, gastric ischemia, necrosis, or perforation. This condition is rare but considered a surgical emergency when acute.

Why is it called so?

The term “upside down stomach” refers to the stomach’s abnormal rotation along its longitudinal (organoaxial) axis, leading to inversion of normal anatomy with the greater curvature positioned above the lesser curvature, effectively turning the stomach “upside down” within the thoracic cavity.

Pathophysiology

The pathophysiology involves a large paraesophageal hiatal hernia that permits the stomach to migrate through the widened esophageal hiatus into the posterior mediastinum. Organoaxial volvulus occurs as the stomach rotates more than 180 degrees around its long axis, causing obstruction of the gastric inlet or outlet and impairing blood flow. This torsion results in the entire stomach lying in the chest, often compressing adjacent thoracic structures and potentially leading to ischemia or strangulation due to compromised gastric vasculature.

Alternative names

• Organoaxial gastric volvulus (when describing the rotation type)
• Type IV paraesophageal hernia (when classification emphasizes hernia type)

Other associated named signs

No specific named radiological signs exclusive to upside down stomach, but related findings include a retrocardiac air-fluid level on chest X-ray and “beaking” at the twist point on contrast fluoroscopy.