Achalasia is a primary esophageal motility disorder that is characterized by a loss of inhibitory neurons in the esophagus with subsequent tonic contraction of the lower esophageal sphincter (LES) and loss of esophageal peristalsis.¹,²Although achalasia is a rare disorder, with an incidence of 1:100,000, recent reports suggest a two- to fourfold increase in incidence due to unclear reasons.¹,²,³,⁴,⁵ Typically, achalasia is idiopathic without a clear inciting cause. However, achalasia can be termed secondary achalasia or pseudoachalasia if a defined etiology causing achalasia is found.⁶ Causes of secondary achalasia range from neoplastic disorders, infiltrative disorders such as amyloidosis, Chagas disease, or circulating antibodies, such as with small-cell lung cancer.¹,⁶

Patients with achalasia typically present with dysphagia to liquids and solids and regurgitation of undigested foods.¹,⁷ Since patients often present with dysphagia, an upper endoscopy, endoscopic ultrasound, and/or a barium esophagram are obtained to rule out a mechanical or infiltrative process. Endoscopic findings that are suggestive of achalasia include mega esophagus or significant dilation of the esophagus, presence of stasis-type mucosal changes, and in some cases, a subjective feeling of difficulty passing the endoscope through the LES.¹,⁷ Barium esophagram will often show a dilated esophagus with an air-fluid level and narrowing at the gastroesophageal junction (GEJ), typically described as a “bird-beak” appearance.¹,³,⁷ However, neither endoscopy nor barium esophagram can make a definitive diagnosis of achalasia, and esophageal manometry is considered the gold standard for diagnosis.

Based on the Chicago Classification of esophageal motility disorders, there are three types of achalasia: (1) type 1, characterized by an elevated median integrative relaxation pressure (IRP) with 100% failed peristalsis; (2) type 2, characterized by an elevated median IRP with 100% failed peristalsis and intermittent
pan-esophageal pressurization, involving greater than or equal to 20% of swallows; (3) type 3, characterized by an elevated median IRP, premature/spastic contractions involving greater than or equal to 20% of swallows, and no normal peristalsis.⁸ There are times where the results of esophageal impedance do not clearly indicate that a patient has achalasia. In those settings, the use of a functional lumen imaging probe (FLIP, Crospon, Galway, Ireland) can be performed. FLIP allows direct measurement of GEJ distensibility and diameter and can serve as a complementary test to aid in the diagnosis of achalasia.¹,⁸

Treatment of achalasia aims at disrupting the hypertonic LES and include medical therapy, botulinum toxin, pneumatic dilation, per-oral endoscopic myotomy (POEM), and Heller myotomy. Since POEM offers achalasia patients a chance at durable symptom control, pneumatic dilation is typically used if a patient is not a candidate for POEM or the patient prefers dilation over POEM. Although patients often require multiple dilations with progressively larger balloons, it serves as an option for treatment of achalasia.