Achalasia is an uncommon disorder of the esophagus. The disorder makes it difficult for food to pass from the esophagus into the stomach.
The esophagus is a muscular tube. It carries food from the mouth to the stomach.
Normally, coordinated contractions of smooth muscle move food through the esophagus. These contractions are called peristaltic waves.
Between the esophagus and stomach is a muscle called the esophageal sphincter (LES). The sphincter surrounds the esophagus. It keeps the esophagus closed. This prevents food and acid from splashing back up into the esophagus from the stomach.
When you swallow, this sphincter relaxes. It opens to allow food to pass into the stomach. At the same time, nerves coordinate the contractions of the esophagus. This moves food into the stomach when the sphincter opens.
In achalasia, the nerve cells in the lower two-thirds of the esophagus and the sphincter are abnormal. This causes uncoordinated or weak peristaltic waves. It also causes the sphincter to remain closed.
The cause of achalasia is unknown. It does not run in families.
Most people with achalasia develop symptoms between the ages of 25 and 60.