Achalasia refers to a condition characterized by the absence of peristalsis in the body of the esophagus and impaired relaxation of the lower esophageal sphincter (LES) during swallowing. Its primary clinical manifestation is intermittent dysphagia. The condition is most commonly observed in individuals aged 20–50, with a slight predominance in females.
Etiology and Pathology
The exact cause of achalasia remains unclear. It is generally believed to result from degeneration, reduction, or absence of nerve ganglia within the muscular layer of the esophagus, leading to impaired propulsion. The inability of the lower esophageal sphincter to relax causes food to accumulate within the esophagus. Over time, this leads to esophageal dilatation, hypertrophy, elongation, tortuosity, and the loss of muscle tone. Chronic food stagnation and irritation of the esophageal mucosa may result in congestion, inflammation, and occasionally ulceration. In very rare cases, there may be malignant transformation after prolonged disease.
Clinical Manifestations
The primary symptom is intermittent dysphagia accompanied by a sense of heaviness or obstruction behind the sternum. The condition often has a prolonged course, with symptoms fluctuating in severity, and episodes are often linked to psychological factors. Cold food frequently triggers symptoms, while swallowing solid food may occasionally create sufficient pressure to facilitate passage. In cases of severe esophageal dilatation, the esophagus may hold large amounts of liquid and food. Aspiration into the trachea may occur during the night, potentially leading to pneumonia as a complication.
Diagnosis
Barium swallow imaging typically shows the absence of peristalsis in the esophageal body, with a characteristic "bird beak" appearance at the distal esophagus and LES. The margins are smooth and regular, with notable dilatation of the proximal esophagus, sometimes accompanied by an air-fluid level. Passage of barium through the lower esophageal sphincter is slow or may be completely obstructed. Esophageal manometry provides a definitive diagnosis. Fiberoptic endoscopy of the esophagus assists in excluding malignancy.
Treatment
Non-Surgical Therapy
Dietary modifications include eating smaller, more frequent meals, chewing thoroughly, and avoiding excessively hot or cold foods. Some patients with mild, early-stage symptoms may benefit from esophageal dilation.
Surgical Therapy
Heller's myotomy, involving the incision of the muscle layer of the lower esophagus and LES, is a straightforward and effective treatment for achalasia, with good outcomes. The muscle incision needs to be thorough, extending to the point where the mucosa protrudes. The dissection typically covers approximately half the esophageal circumference. Care must be taken to avoid mucosal perforation or damage to the vagus nerve. In some cases, an anti-reflux procedure, such as fundoplication, may be added to the myotomy.
Conventional open surgery is usually performed via abdominal or left thoracic approaches. However, minimally invasive techniques using laparoscopic or thoracoscopic approaches are now preferred due to reduced trauma and faster recovery. With advancements in endoscopic techniques in recent years, certain cases of achalasia can also be treated endoscopically.