Achalasia is a disorder of esophageal motility characterized clinically by progressive.dysphagia and regurgitation of previously ingested food. It is associated with distal obstruction to emptying in the absence of an identifiable organic lesion. This condition has been recognized since Thomas Willis orginally described the clinical features and performed the first esophageal dilation with a whale bone in the 17th century.
There are two main defects in achalasia: (1) obstruction at the esophagogastric junction, and (2) abnormal esophageal peristalsis. Obstruction was initially attributed to spasm of the cardia or lower esophageal sphincter (LES), and the condition was called "cardiospasm." Subsequently, uninfused manometric techniques revealed that the LES was not hypertensive, but showed absence of relaxation with swallowing, resulting in the term "achalasia," which literally means "failure of relaxation." With refinements in manometric techniques and use of slow infusion of fluid into recording catheters, it became apparent that there was some
Castell DO. Achalasia and Diffuse Esophageal Spasm. Arch Intern Med. 1976;136(5):571-579. doi:10.1001/archinte.1976.03630050053010