• Clinical science

Achalasia

Abstract

Achalasia is a failure of the lower esophageal sphincter (LES) to relax that is caused by the degeneration of inhibitory neurons within the esophageal wall. It is classified as either primary (idiopathic) or secondary (in the context of another disease). In patients with achalasia, the chief complaint is dysphagia to both solids and liquids, although regurgitation, retrosternal pain, and weight loss may also occur. Upper endoscopy, barium esophagram, and manometry play complementary roles in the diagnosis of achalasia. While upper endoscopy and/or barium esophagram are often obtained initially, manometry usually confirms the diagnosis, and upper endoscopy is indicated to rule out a malignant underlying cause. In good surgical candidates, achalasia is usually treated with pneumatic dilation or myotomy. In most other cases, an injection of botulinum toxin is attempted. If these measures fail to provide relief, medical therapy (e.g., nifedipine) is indicated.

Epidemiology

  • Rare disorder (∼ 1.6/100,000 individuals)
  • Most commonly occurs in middle-aged individuals

References:[1]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

References:[1]

Pathophysiology

  • Swallowing is controlled through excitatory (acetylcholine, substance P) and inhibitory (NO, VIP) neurohumoral substances.
  • Degeneration of inhibitory neurons within the myenteric plexuses (Auerbach's plexus) → deficient inhibitory neurotransmitters → failure to relax and higher resting pressure of the LES, as well as dysfunctional peristalsis → esophageal dilation proximal to LES

References:[1]

Clinical features

  • Dysphagia to solids and liquids
  • Regurgitation
  • Retrosternal pain and cramps
  • Weight loss

References:[1]

Diagnostics

  • Approach:
    • In general, all patients with suspected achalasia should initially undergo upper endoscopy and/ or barium esophagram; findings may support the diagnosis.
    • Manometry is indicated to establish the diagnosis (confirmatory test of choice), irrespective of the initial imaging findings.
    • If manometry is inconclusive and a barium esophagram was not obtained initially, esophagram can also play a confirmatory role.
    • Endoscopy should be performed to rule out pseudoachalasia because the presentation and manometric findings of a mechanical cause of obstruction (e.g., a malignancy) may mimick achalasia.
  • Barium esophagram: supportive and/or confirmatory test
    • "Bird-beak appearance": dilation of the distal esophagus with narrowing of the gastroesophageal junction
    • Delayed barium emptying or barium retention
  • Upper endoscopy: to rule out pseudoachalasia
    • Usually normal
    • May show retained food in esophagus or increased resistance of LES during passage with endoscope
    • If malignancy is suspected, biopsy and endoscopic ultrasound are indicated
  • Manometry: confirmatory test of choice
    • Lack of peristalsis in the lower two-thirds of the esophagus
    • Incomplete or absent relaxation of the LES
    • Increased resting pressure
    • No evidence of mechanical obstruction
  • Chest x-ray
    • Widened mediastinum
    • Air-fluid level on lateral view
    • Possible absence of gastric air bubble

References:[1][2]

Differential diagnoses

Differential diagnosis of esophageal motility disorders

Esophageal motility disorders range from hypomotile dysfunction (achalasia) to hypermotile dysfunction (diffuse esophageal spasm, nutcracker esophagus); of the esophagus. They have similar symptoms with dysphagia, chest pain, and regurgitation of food, but are differentiated based on findings in esophagograms and esophageal manometry.

Normal esophagus

Achalasia

Diffuse esophageal spasm

(Corkscrew esophagus/rosary bead esophagus)

Hypertensive peristalsis

(Supersqueeze esophagus/nutcracker esophagus)

Symptoms
  • None
  • Progressive dyphagia
  • Regurgitation of undigested food/saliva
  • Weight loss
  • Dysphagia
  • Retrosternal chest pain Squeezing type, occurs with eating
  • Regurgitation

Lower esophageal sphincter (LES) pressure and relaxation

  • Normal
  • LES pressure: high (failure to relax)
  • LES relaxation: incomplete/absent
  • Normal
  • Normal

Contraction waves

  • Progressive (towards the LES)
  • Simultaneous, non-progressive

  • Simultaneous, non-progressive, repetitive
  • Long duration
  • High pressure waves
  • Amplitude of the contractions exceed 2 standard deviations from the norm

Esophagogram

  • Normal
  • Dilated esophagus which tapers distally (Bird's beak appearance/rat tail appearance)
  • LES spasm and delayed barium emptying
  • Normal progressive contractions, but high amplitude (supersqueeze, nutcracker)

Esophageal manometry

  • Normal (40–100 mm Hg)
  • High LES pressure
  • High esophageal body pressure
  • Low peristaltic contraction pressure
  • Simultaneous multi-peak contractions
  • High pressure contractions
  • Intermittent normal peristalsis
  • Hypertensive contractions (> 400 mm Hg)
Treatment
  • See “Treatment”
  • Medical
  • Endoscopic
    • Bougie dilation (severe dysphagia)
    • Botox injections
  • Surgery: long esophagomyotomy (for severe symptoms)
  • Medical

The differential diagnoses listed here are not exhaustive.

Treatment

If a low surgical risk

The preferred treatment often depends on the surgeon and the patient's situation. However, attempting pneumatic dilation before myotomy is gaining popularity because it is less invasive and the time of recovery is faster. This approach is already more popular in Europe.

  • Pneumatic dilation
    • Endoscope-guided graded dilation of the LES that tears the surrounding muscle fibers with the help of a balloon
    • The success rate at one month is ∼ 85%; perforation risk is ∼ 2%. Because of the risk of perforation, which necessitates a second surgery, only good surgical candidates can undergo pneumatic dilation
    • Approx. one-third of patients relapse within four to six years and require treatment again
  • LES myotomy (Heller myotomy)

If a high surgical risk

  • Botulinum toxin injection in the LES
    • Less invasive compared to pneumatic dilation and Heller myotomy
    • A good choice for patients who are poor surgical candidates
    • Unsatisfying results in young patients and long-term treatment
    • More than 50% of patients require treatment again within 6–12 months.
    • Can cause scarring; may complicate future myotomy
  • If other measures are unsuccessful: nifedipine or calcium channel blockers

References:[2][3]

Complications

References:[1][3]

We list the most important complications. The selection is not exhaustive.