From the Guidelines
Achalasia is classified as an esophageal motility disorder. It is characterized by impaired relaxation of the lower esophageal sphincter and loss of peristalsis in the distal esophagus, as described in the Chicago Classification system 1. This condition results from degeneration of inhibitory neurons in the myenteric plexus, leading to unopposed excitatory stimulation. Patients with achalasia typically experience progressive dysphagia to both solids and liquids, regurgitation of undigested food, chest pain, and weight loss.
Key Characteristics of Achalasia
- Impaired relaxation of the lower esophageal sphincter
- Loss of peristalsis in the distal esophagus
- Degeneration of inhibitory neurons in the myenteric plexus
- Unopposed excitatory stimulation
Comparison with Other Conditions
Unlike the other options listed, which are structural abnormalities, achalasia represents a functional disorder of esophageal motility.
- Esophageal stricture is a narrowing of the esophagus
- Esophageal web is a thin membrane of tissue that protrudes into the esophageal lumen
- Schatzki ring is a circumferential mucosal structure at the gastroesophageal junction
- Zenker diverticulum is an outpouching of the posterior pharyngeal wall These conditions cause mechanical obstruction rather than disordered motility. The diagnosis of achalasia is typically established using high-resolution manometry (HRM) to demonstrate impaired deglutitive lower esophageal sphincter (LES) relaxation and absent peristalsis, as recommended in the AGA clinical practice update 1.
Diagnosis and Treatment
A comprehensive evaluation is paramount in patients to confirm the diagnosis before consideration of treatment options such as per-oral endoscopic myotomy (POEM) 1. The role of POEM in the treatment of achalasia has been expanding, with recent studies suggesting its effectiveness in type III achalasia and other non-achalasia spastic motility disorders 1. However, careful consideration of potential false positives and confirmatory compliance testing are mandatory to exclude other conditions such as gastroesophageal reflux disease (GERD) and document symptomatic delayed esophageal emptying.
Recent Developments
Recent studies have reported reasonable outcomes in carefully selected patients with EGJOO and other non-achalasia spastic motility disorders treated with POEM, although the long-term success rates appear somewhat lower compared with POEM for the classic achalasia sub-types 1. Overall, achalasia is a distinct esophageal motility disorder that requires careful diagnosis and treatment, and POEM has emerged as a promising treatment option for selected patients.
From the Research
Esophageal Motility Disorders
- Esophageal motility disorders (EMDs) are a group of conditions that affect the movement of food through the esophagus, including achalasia, esophagogastric junction outflow obstruction, absent contractility, distal esophageal spasm, hypercontractile esophagus, and ineffective esophageal motility 2.
Classification of Achalasia
- Achalasia is classified as an esophageal motility disorder, characterized by abnormalities in peristalsis and lower esophageal sphincter (LES) relaxation 3, 4, 5, 6.
Diagnosis and Management
- The diagnosis of achalasia depends on classic findings using high-resolution manometry, showing either failed or simultaneous contractions with associated normal or high LES pressures with no or incomplete relaxation with swallows 3.
- Treatment options for achalasia include pneumatic dilation, surgical myotomy, per-oral endoscopic myotomy, and botulinum toxin (Botox) or other medical therapies 3, 4, 5, 6.
Comparison with Other Conditions
- Esophageal stricture, esophageal web, Schatzki ring, and Zenker diverticulum are not classified as esophageal motility disorders, but rather as structural or anatomical abnormalities of the esophagus.
- Achalasia is the only condition listed that is classified as an esophageal motility disorder, according to the provided studies 2, 3, 4, 5, 6.