Definition

Achalasia is a primary esophageal motor disorder in which there is impaired relaxation of the esophagogastric junction and absent normal esophageal peristalsis.

Pathophysiology

The fundamental abnormality involves dysfunction and loss of inhibitory neurons within the myenteric plexus.

• Loss of inhibitory neural input
• Impaired EGJ relaxation
• Loss of normal peristalsis
• Progressive esophageal dilatation

Clinical Presentation

The classical presentation includes dysphagia to both solids and liquids, regurgitation and retrosternal discomfort.

• Dysphagia
• Regurgitation
• Retrosternal chest pain
• Weight loss
• Nocturnal cough
• Aspiration

Differential Diagnosis

Important differentials include mechanical obstruction, esophageal malignancy, benign stricture, Chagas disease and pseudoachalasia.

• Esophageal carcinoma
• Gastroesophageal junction malignancy
• Benign esophageal stricture
• Chagas disease
• Pseudoachalasia
• Other motility disorders

Endoscopy

Upper GI endoscopy is important to exclude mechanical obstruction and malignancy, especially at the gastroesophageal junction.

Retained food or fluid may be seen. The EGJ can be tight, although the endoscope can often be passed with gentle pressure in uncomplicated achalasia.

Barium Swallow

The classic contrast-study finding is smooth tapering of the distal esophagus at the gastroesophageal junction, producing the characteristic bird-beak appearance.

• Distal esophageal narrowing
• Proximal esophageal dilatation
• Delayed esophageal emptying
• Bird-beak appearance

Timed Barium Esophagram

Timed barium esophagram objectively assesses esophageal emptying by measuring retained contrast at predetermined time points.

It can be particularly useful when assessing response to treatment or investigating persistent or recurrent symptoms.

High-Resolution Manometry

High-resolution esophageal manometry is the key physiological investigation for confirming achalasia and classifying it into Type I, Type II and Type III.

• Elevated integrated relaxation pressure
• Absent normal peristalsis
• Assessment of panesophageal pressurization
• Assessment of premature or spastic contractions

Type I Achalasia

Type I, or classic achalasia, is characterized by impaired EGJ relaxation with absent normal peristalsis and without significant panesophageal pressurization.

Type II Achalasia

Type II achalasia is characterized by absent normal peristalsis with panesophageal pressurization.

Type III Achalasia

Type III is the spastic subtype of achalasia and is characterized by premature or spastic contractions of the esophageal body.

Eckardt Score

The Eckardt score is used to assess symptom severity and response to treatment.

Each component is scored from 0 to 3, giving a maximum score of 12.

FLIP

Functional Luminal Imaging Probe, or FLIP, assesses esophageal and EGJ distensibility.

FLIP can complement manometry and may provide additional physiological information in selected patients.

Pseudoachalasia

Pseudoachalasia is an achalasia-like presentation caused by another disease, particularly malignancy involving the gastroesophageal junction.

Suspicion should increase with older age, rapid progression, significant weight loss and difficulty passing the endoscope through the EGJ.

Treatment Overview

Definitive treatment aims to reduce the functional obstruction at the gastroesophageal junction.

• Pneumatic dilatation
• Laparoscopic Heller myotomy
• Peroral endoscopic myotomy

Botulinum toxin and pharmacological treatment have more limited roles and may be considered in selected patients.