Achalasia
Achalasia is an esophageal motility disorder caused by nerve degeneration, resulting in failure of the lower esophageal sphincter to relax and progressive difficulty swallowing.
Emergency Management: Esophageal perforation post-pneumatic dilation, requiring immediate NPO status, broad-spectrum IV antibiotics, and surgical consultation for repair.
A rare primary esophageal motility disorder characterized by the absence of esophageal peristalsis and impaired relaxation of the lower esophageal sphincter (LES) in response to swallowing. This leads to functional obstruction at the gastroesophageal junction. The core pathology involves the degeneration of inhibitory ganglion cells in the myenteric (Auerbach) plexus of the esophagus.
Detailed Overview
Achalasia manifests progressively with dysphagia to both solids and liquids, regurgitation of undigested food, and weight loss. The loss of inhibitory neurotransmitters (nitric oxide and vasoactive intestinal peptide) leaves unopposed excitatory tone (acetylcholine), causing LES hypertonia. Over time, the esophagus dilates and becomes tortuous (sigmoid esophagus), predisposing to aspiration and squamous cell carcinoma. Timely intervention aims to relieve the outflow obstruction, though peristalsis is rarely restored.
Epidemiology & Demographics
Incidence: 1 to 3 per 100,000 individuals annually. Prevalence: 10 per 100,000. Peak age of onset is between 25 and 60 years. Gender ratio is roughly equal (1:1). Geographically ubiquitous with no specific regional predilection.
Etiological Mechanism
Most cases are idiopathic. The underlying cause is the autoimmune or viral-mediated destruction of the myenteric plexus ganglion cells. Chagas disease (Trypanosoma cruzi infection) can cause secondary achalasia by directly destroying these nerve plexuses.
Primary Causes
Idiopathic immune-mediated destruction
Trypanosoma cruzi (Chagas disease)
Malignancy (pseudoachalasia due to tumor infiltration of GE junction)
Amyloidosis
Sarcoidosis
Inflammatory infiltrates (T lymphocytes) target the myenteric plexus, leading to apoptosis of inhibitory neurons. The loss of nitric oxide and VIP-producing neurons eliminates the relaxation reflex of the LES. Concurrently, loss of the intramural neural network abolishes organized peristaltic contractions in the esophageal body. The unopposed cholinergic action maintains the LES in a contracted state, causing dysphagia and subsequent proximal esophageal dilation.
Diagnostic Criteria & Guidelines
High-Resolution Manometry (HRM) is the gold standard: defined by an Integrated Relaxation Pressure (IRP) > 15 mmHg and 100% failed peristalsis. Supportive findings on Barium Swallow: 'bird-beak' appearance at the GE junction.
Pneumatic Dilation (PD) utilizing a 30-35 mm Rigiflex balloon, or Laparoscopic Heller Myotomy (LHM) with a partial fundoplication (Dor or Toupet). Peroral Endoscopic Myotomy (POEM) is strongly recommended for Type III Achalasia.
Second-Line & Adjunctive Therapy
Botulinum toxin A injection (100 units endoscopically into the LES) for patients who are poor surgical candidates, lasting 6-12 months. Pharmacotherapy: Nifedipine 10-20 mg sublingual or Isosorbide dinitrate 5 mg sublingual 15-30 minutes before meals.
Surgical & Procedural Management
Laparoscopic Heller Myotomy (LHM) involving incision of the circular muscle layer of the lower esophagus and proximal stomach. Esophagectomy in end-stage 'sigmoid' esophagus unresponsive to therapy.
Patient Counseling & Advice
Inform the patient that treatments aim to palliate symptoms by relieving obstruction, but they do not cure the underlying nerve damage or restore peristalsis. Warn about the increased risk of post-treatment GERD and the necessity of long-term PPI therapy after myotomy.
Follow-Up & Monitoring Schedule
Clinical assessment with the Eckardt Score every 1-2 years. Annual EGD with Lugol chromoendoscopy starting 10-15 years after symptom onset for SCC surveillance is controversial but often recommended in severe retention cases.
Preventive Strategies
No primary prevention strategies exist as the disease is largely idiopathic. Preventing Chagas disease via vector control in endemic areas is the only known preventative measure for secondary cases.
Over 90% of patients achieve significant symptom relief with LHM, PD, or POEM. However, the disease is chronic. Without treatment, severe malnutrition and fatal aspiration can occur.