Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.
Achalasia is a rare disease of the muscle of the
esophagus (swallowing tube). The term achalasia means "failure to relax" and
refers to the inability of the lower esophageal sphincter (a ring of muscle
between the lower esophagus and the stomach) to open and let food pass into the stomach. As a result, patients with
achalasia have difficulty in swallowing food.
How does the normal esophagus function?
The esophagus has three functional parts. The uppermost
part is the upper esophageal sphincter, a specialized ring of muscle that forms
the upper end of the tubular esophagus and separates the esophagus from the
throat. The upper sphincter remains closed most of the time to prevent food in
the main part of the esophagus from backing up into the throat. The main part of
the esophagus is referred to as the body of the esophagus, a long, muscular tube
cm (8 in) in length. The third functional part of the esophagus is the lower
esophageal sphincter, a ring of specialized esophageal muscle at the junction of
the esophagus with the stomach. Like the upper sphincter, the lower sphincter
remains closed most of the time to prevent food and acid from backing up into
the body of the esophagus from the stomach.
The upper sphincter relaxes with swallowing to allow
food and saliva to pass from the throat into the esophageal body. The
muscle in the upper esophagus just below the upper sphincter then contracts,
squeezing food and saliva further down into the esophageal body. The ring-like
contraction of the
muscle progresses down the body of the esophagus, propelling the food and saliva
towards the stomach. (The progression of the muscular contraction through the
esophageal body is referred to as a peristaltic wave.). By the time the
peristaltic wave reaches the lower sphincter, the sphincter has opened, and the
food passes into the stomach.
oral medications that help to relax the lower esophageal sphincter
such as nitrates (for example, isosorbide dinitrate
[Isordil]) and calcium channel blockers (for example, nifedipine
[Procardia] and verapamil [Calan]);
dilation (stretching of the lower
esophagomyotomy (surgery to
cut the sphincter); and
the injection of botulinum toxin
(Botox) into the
All four of these treatments reduce the pressure within the lower esophageal
sphincter to allow easier passage of food from the esophagus into the stomach.