American Registry of Radiologic Technologists (ARRT) Practice Exam

Achalasia is a disorder characterized by the inability of the esophagus to move food down to the stomach due to the failure of the lower esophageal sphincter to relax properly. This results in the dilation of the esophagus above the sphincter as food accumulates because it cannot pass through into the stomach.

The condition typically leads to symptoms such as difficulty swallowing, regurgitation of undigested food, and chest pain. Over time, the lack of proper movement and pressure changes in the esophagus cause it to widen, or dilate, above the obstruction created by the sphincter not functioning correctly.

While swelling, contraction, and infection of the esophagus could relate to various other conditions, they do not capture the essence of what occurs in achalasia, which is primarily the failure of peristalsis (the rhythmic contractions that propel food) and the resultant accumulation and dilation. Therefore, dilation is the key feature of achalasia.