44. Achalasia

1. Definition

• Achalasia → primary oesophageal motility disorder with failure of the lower oesophageal sphincter (LOS) to relax on swallowing and loss of peristalsis in the oesophageal body
• Pseudoachalasia → same picture caused by a tumour at the cardia

2. Epidemiology

• Incidence about 1 per 100,000 a year
• Men and women equally
• Mean age at diagnosis about 50 years; peaks at 30 and 60 years
• Chagas disease → common cause in South America

3. Aetiology and risk factors

• Primary → cause unknown:
  • Autoimmune reaction, possibly after a viral infection (herpes, varicella-zoster)
  • Genetic susceptibility (HLA types), Down's syndrome, Allgrove syndrome
• Secondary:
  • Chagas disease → Trypanosoma cruzi destroys ganglion cells (also megacolon, cardiomyopathy)
  • Pseudoachalasia → cancer of the cardia, lymphoma, paraneoplastic (small cell lung cancer)
  • After fundoplication or gastric banding

4. Pathogenesis

1. Inflammation and loss of inhibitory neurons in the myenteric (Auerbach's) plexus
2. These neurons release nitric oxide and vasoactive intestinal peptide → needed for LOS relaxation and peristalsis
3. Excitatory (acetylcholine) neurons are spared → LOS stays closed, often hypertensive
4. No peristalsis → food and fluid stay in the oesophagus
5. Oesophagus dilates and lengthens → megaoesophagus, sigmoid oesophagus
6. Stasis → oesophagitis → higher risk of squamous cell carcinoma

5. Classification

High-resolution manometry (Chicago classification v4.0)

• Diagnosis → raised integrated relaxation pressure (IRP) plus absent peristalsis
• Type I (classic) → no pressure in the oesophageal body; dilated oesophagus
• Type II → pan-oesophageal pressurisation; best response to any treatment
• Type III (spastic) → premature spastic contractions; best treated by a long myotomy (POEM)

Radiological stage (by oesophageal diameter)

• I < 4 cm, II 4–6 cm, III > 6 cm, IV sigmoid oesophagus

Related motility disorders

• Diffuse oesophageal spasm → premature (simultaneous) contractions; chest pain and dysphagia; "corkscrew" oesophagus on barium
• Hypercontractile ("jackhammer") oesophagus
• Oesophagogastric junction outflow obstruction

6. Clinical picture

Symptoms

• Dysphagia to both solids and liquids from the start (fluids can be worse early) → typical of a motility disorder
• Regurgitation of undigested food, often at night
• Chest pain (more in type III)
• Weight loss
• Heartburn → from fermenting food, not reflux; many are wrongly treated with PPIs first
• Nocturnal cough, aspiration pneumonia
• Patients eat slowly, drink to wash food down, stretch or stand to swallow

Signs

• Often normal
• Weight loss, malnutrition
• Signs of aspiration in the chest
• Eckardt score → dysphagia, regurgitation, chest pain, weight loss (0–12); used to judge response

7. Diagnosis

Imaging

• Barium swallow (timed):
  • Dilated oesophagus with an air-fluid level
  • "Bird's beak" or "rat's tail" smooth narrowing at the cardia
  • Slow emptying; absent gastric air bubble on chest X-ray
  • Sigmoid shape in late disease
• CT → if pseudoachalasia is suspected (age > 60, short history, rapid weight loss)

Endoscopy

• Upper GI endoscopy in every patient → exclude cancer of the cardia (pseudoachalasia) and stricture
• Food residue, dilated oesophagus; scope "pops" through the tight LOS

Physiology

• High-resolution manometry → gold standard; gives the type
• pH monitoring → to separate achalasia from GORD; also after treatment

8. Differential diagnosis

• Pseudoachalasia → cancer of the cardia
• Peptic stricture, eosinophilic oesophagitis
• Diffuse oesophageal spasm, jackhammer oesophagus
• Scleroderma → weak LOS, reflux, absent peristalsis
• Oesophageal cancer
• Chagas disease

9. Treatment

• Aim → relieve the obstruction at the LOS; none restores peristalsis
• Choice depends on type, age, fitness and local skill

Conservative

• Drugs → nifedipine or nitrates before meals; short effect, side effects; for patients unfit for anything else
• Botulinum toxin → 100 units injected into the LOS at endoscopy:
  • Blocks acetylcholine release
  • Relief in about 80% at 1 month, 40% at 1 year
  • For the elderly or unfit; scars the planes and makes later myotomy harder
• Pneumatic dilatation:
  • Graded balloons (30 → 35 → 40 mm) under X-ray
  • Success about 80–85%; about 25% need repeat dilatation
  • Perforation in about 2–4%
  • Poorer results → age < 40, men, type I and III

Surgical

• Laparoscopic Heller myotomy + partial fundoplication → standard operation:
  1. Divide the muscle layers (longitudinal and circular) down to the mucosa
  2. Length → about 6 cm on the oesophagus and 2–3 cm onto the stomach
  3. Add an anterior (Dor) or posterior (Toupet) partial fundoplication → reflux falls from about 48% to 9%
  4. Success about 90%
  5. Complications → mucosal perforation (repaired at once), reflux, recurrent dysphagia
• Peroral endoscopic myotomy (POEM):
  • Submucosal tunnel from inside the oesophagus; circular muscle divided
  • Success > 90%; best for type III (long myotomy)
  • Main drawback → reflux in about 50% (no fundoplication)
• End-stage sigmoid oesophagus or failed treatments → oesophagectomy
• Follow-up → endoscopy surveillance is debated; cancer risk stays raised

10. Complications

Of disease

• Aspiration pneumonia, lung abscess
• Malnutrition, weight loss
• Squamous cell carcinoma → about 10–50 times more risk; late
• Megaoesophagus

Of treatment

• Perforation → dilatation (2–4%), myotomy, POEM
• GORD, peptic stricture, Barrett's oesophagus
• Recurrent dysphagia → incomplete myotomy, scar, tight wrap