Table 1.

Etiologies of esophagogastric junction outflow obstruction

Condition	Comments
Early or incompletely expressed achalasia	The so called functional EGJOO, akin to achalasia
Mechanical process	Examples include EoE, esophagitis, hiatal hernia, strictures, rings, tumors at the EGJ, obstructing esophageal varices.
Esophageal wall stiffness	Infiltrative esophageal processes, fibrosis, or malignancy
Extrinsic vascular compression	e.g., aneurysmal dilatation of the aorta
Central obesity	Due to increased intra-abdominal pressure
Opiate effect	EGJOO is more prevalent in chronic opiate users
Anatomical changes	Examples: Operations that affect EGJ (e.g., fundoplication, bariatric surgery), paraesophageal hernia
False-positive finding (normal variant)	Measurement error

EGJ: Esophagogastric junction; EGJOO: Esophagogastric junction outflow obstruction; EoE: Eosinophilic esophagitis.