Achalasia is a rare and complex swallowing disorder characterized by the inability of the lower esophageal sphincter (LES) to relax properly, combined with a loss of coordinated muscular contractions in the esophagus.

This dysfunction leads to impaired passage of food and liquids from the esophagus into the stomach, creating significant challenges with swallowing and digestion.

Pathophysiology and Mechanisms

The crux of achalasia lies in a disruption of nerve signaling within the esophageal muscles. Normally, swallowing initiates a well-coordinated chain reaction where muscles of the esophageal body contract sequentially (peristalsis) to propel ingested food downward while the LES simultaneously relaxes to allow passage into the stomach.

In achalasia, there is degeneration of the myenteric plexus neurons, especially those that inhibit muscular contraction. This loss leads to a hypertensive, unrelaxed LES that acts almost like a closed valve, alongside a failure of the esophageal muscles to generate effective peristaltic waves.

The precise cause of this nerve degeneration remains unclear. Hypotheses include autoimmune responses targeting the esophageal nerve cells, viral infections triggering inflammation, or genetic susceptibility influencing immune or neural pathways. Secondary achalasia can sometimes result from infections like Chagas disease or malignancies infiltrating esophageal tissue.

Clinical Manifestations

Symptoms of achalasia typically arise subtly and evolve over several years. The most common complaint is dysphagia, or difficulty swallowing, which affects both solids and liquids. Affected individuals may frequently feel as though food is stuck in the chest or throat. Regurgitation of undigested food is common due to the obstruction and accumulation within the esophagus, which can also cause halitosis or a bitter taste.

Additional symptoms often include chest discomfort or pain that can mimic heart-related conditions, persistent heartburn, and increased belching. As food accumulates and risks aspiration, coughing—especially nocturnal may occur.

Diagnostic Insights

Diagnostic evaluation typically involves a combination of barium swallow imaging, esophageal manometry, and endoscopy. Barium studies reveal a characteristic dilated esophagus with a narrowed "bird-beak" appearance at the LES. Manometry is crucial for confirming achalasia by demonstrating the absence of peristalsis and failure of LES relaxation during swallowing.

Endoscopy is essential to rule out mechanical obstructions or cancer mimicking achalasia symptoms.

Types of Achalasia

Achalasia is subdivided into three types based on manometric patterns:

Type I (classic achalasia): Minimal esophageal pressurization with absent peristalsis and impaired LES relaxation.

Type II: Pan-esophageal pressurization during swallows, reflecting some retained muscle tone.

Type III: Spastic contractions or premature contractions of the esophageal body, accompanied by impaired LES relaxation.

Treatment Options and Prognosis

Though achalasia lacks a definitive cure, multiple interventions aim to relieve symptoms by reducing the LES pressure and improving esophageal emptying. Treatment modalities include pneumatic dilation, which forcibly stretches the LES muscle; Heller myotomy, a surgical cutting of the sphincter muscle; and peroral endoscopic myotomy (POEM), a minimally invasive endoscopic approach to muscle division.

Living with Achalasia

The progressive nature of achalasia can affect nutrition and psychosocial well-being due to ongoing swallowing difficulties. Dietary modifications—such as eating smaller, more frequent meals, thorough chewing, and avoiding problematic foods may help reduce symptoms alongside medical treatment. Awareness and early diagnosis are crucial, as prolonged obstruction can cause irreversible esophageal damage.

Dr. M. F. Vaezi, a highly respected physician and researcher, states "Achalasia is an esophageal motility disorder characterized by aberrant peristalsis and insufficient relaxation of the lower esophageal sphincter."

Achalasia is a rare but serious swallowing disorder arising from nerve damage that impairs esophageal muscle coordination and sphincter relaxation. Its hallmark symptoms include difficulty swallowing, regurgitation, chest discomfort, and weight loss, progressing over time without intervention.

Understanding the complex neuro-muscular dysfunction underlying achalasia provides valuable insight into its challenging clinical features and guides targeted interventions.