Achalasia is an acquired disorder of the esophageal smooth muscle characterized by loss of peristalsis in the distal two-thirds of the esophagus and impaired relaxation in the lower esophageal sphincter. In the United States, the majority of cases of achalasia are idiopathic. Chagas disease is an important cause of achalasia worldwide. Patients typically present with dysphagia to both solids and liquids, accompanied by episodic regurgitation of swallowed food. Patients cope by eating slowly and drinking lots of water to wash food down. They may also cope with achalasia by repositioning the head, neck, and shoulder to facilitate the passage of a food bolus. Additionally, patients may complain of chest pain, weight loss, and recurrent pulmonary complications secondary to aspirations, leading to lung abscesses, hemoptysis, or bronchiectasis. Esophageal manometry is needed to confirm the diagnosis of achalasia and reveals incomplete relaxation of the lower esophageal sphincter, elevated resting lower esophageal sphincter pressure, and aperistalsis of the esophageal body. Treatment of achalasia includes supportive measures, medical therapy, injection of botulinum toxin into the lower esophageal sphincter during endoscopy, forceful dilatation (mechanical, pneumatic, or hydrostatic), and surgical management. Supportive measures include adaptive measures, such as chewing food to pea soup consistency before swallowing, sleeping with trunk elevation, and eating hours before sleep. Medical therapy may improve early stages of achalasia and includes antimuscarinic agents (dicyclomine), sublingual nitroglycerine, long-acting nitrates, and calcium channel blockers.

In patients with equivocal esophageal manometry results, barium esophagram (A) should be performed to assess esophageal emptying and esophagogastric junction morphology. Barium esophagram may reveal dilation of the esophagus, narrow esophagogastric junction with “bird-beak” appearance caused by persistently contracted lower esophageal sphincter, aperistalsis, and delayed emptying of barium. It is not sensitive for achalasia and may be normal in up to one-third of individuals with achalasia. Endoscopic ultrasound (B) may demonstrate a thickened circular muscle layer at the lower esophageal sphincter and through the smooth muscle esophagus. Although its ability to differentiate achalasia from pseudoachalasia has not been established, endoscopic ultrasound is still useful for characterizing tumors of the distal esophagus and gastric cardia. Upper gastrointestinal endoscopy (D) may show a dilated esophagus that contains large quantities of residual materials. In patients with achalasia, the lower esophageal sphincter does not spontaneously open to allow the effortless passage of the endoscope into the stomach but can typically be traversed easily with gentle pressure on the endoscope. In addition, gastrointestinal endoscopy often shows normal esophageal mucosa in achalasia, although it can also demonstrate nonspecific changes secondary to retained food and pills, such as erythema and ulceration. It is not the diagnostic test of choice for achalasia.