Functional assessment of achalasia
The treatment of achalasia is dependent on evaluation of esophageal function of patients with this progressive disorder. This begins with an evaluation of its symptoms and their severity. The Eckardt scale is the most widely used, though it has limitations. Timed barium swallow evaluation provides a simple inexpensive means to evaluate esophageal emptying across a non-relaxing lower esophageal sphincter, before and after therapy. High resolution esophageal manometry has improved our ability to assess both esophageal body and sphincteric function. It has allowed identification of manometric phenotypes, which help prognosticate response to therapy. Esophageal impedance measurements of liquid swallows and esophageal emptying are a new and promising advance. Endoscopic ultrasound can measure esophageal muscle thickness, but has an adjunctive role mainly aimed at excluding structural abnormalities, such as malignancy causing secondary achalasia.