Achalasia

Achalasia (primary achalasia) refers to a failure of organised oesophageal peristalsis with an impaired relaxation of the lower oesophageal sphincter (LOS), resulting in often marked dilatation of the oesophagus and food stasis. Obstruction of the distal oesophagus (often due to tumour) has been termed "secondary achalasia" or "pseudoachalasia".

Primary achalasia is most frequently seen in middle and late adulthood (age 30 to 70) with no gender predilection 6. In most cases, achalasia is idiopathic; however, an identical appearance is seen in patients with Chagas disease. Authors differ as to whether to reserve the term achalasia for idiopathic cases or to include Chagas disease.

Patients typically present with

  • dysphagia for both solids and liquids: this is in contradistinction to dysphagia for solids only in cases of oesophagal carcinoma 7
  • chest pain/discomfort
  • eventual regurgitation

Symptoms are initially intermittent. Patients may also present with complications of long-standing achalasia:

  • oesophageal carcinoma
    • the most dreaded complication, seen in approximately 5%, most often in the mid-oesophagus
    • thought to occur because of chronic irritation of the mucosa by stasis of food and secretions
  • aspiration pneumonia: the chronic presence of fluid debris in the oesophagus makes patients very prone to aspiration
  • candida oesophagitis
  • acute airway obstruction: this is a rare complication requiring immediate oesophageal decompression with a nasogastric tube

Peristalsis in the distal smooth muscle segment of the oesophagus may be lost due to an abnormality of the Auerbach plexus (responsible for smooth muscle relaxation), resulting in weak, uncoordinated contractions that are uncoordinated and therefore non-propulsive. The abnormality may also occur in the vagus nerve or its dorsal motor nucleus.

The lower oesophageal sphincter eventually fails to relax, either partially or completely, with elevated pressures demonstrated manometrically 4. Early in the course of achalasia, the lower oesophageal sphincter tone may be normal or changes may be subtle.

Achalasia characteristically involves a short segment (less than 3.5 cm in length) of the distal oesophagus.

Plain radiograph

Chest x-ray findings include:

  • right convex opacity behind the right cardiac border; occasionally left convex opacity if the thoracic aorta is tortuous
  • air-fluid level due to stasis in a thoracic oesophagus filled with retained secretions and food
  • small or absent gastric air bubble
  • anterior displacement and bowing of the trachea on the lateral view
  • patchy alveolar opacities, usually bilateral, may be seen: represent acute pneumonitis or chronic aspiration pneumonia
Fluoroscopy with barium swallow

A barium swallow is able to not only confirm that the oesophagus is dilated but is also able to assess for mucosal abnormalities. Findings include:

  • bird beak sign
  • oesophageal dilatation
  • tram track appearance 8: central longitudinal lucency bounded by barium on both sides
  • incomplete lower oesophageal sphincter relaxation that is not coordinated with oesophageal contraction
  • pooling or stasis of barium in the oesophagus when the oesophagus has become atonic or non-contractile (a late feature in the disease)
  • uncoordinated, non-propulsive, tertiary contractions (see case 1)
  • failure of normal peristalsis to clear the oesophagus of barium when the patient is in the recumbent position, with no primary waves identified
  • when the barium column is high enough (with the patient standing), the hydrostatic pressure can overcome the lower oesophageal sphincter pressure, allowing passage of oesophageal content
  • a hot or carbonated drink during the exam may help visualise sphincter relaxation and barium emptying
CT

Patients with uncomplicated achalasia demonstrate a dilated, thin walled oesophagus filled with fluid/food debris.

Overall, CT has little role in directly assessing patients with achalasia, but is useful in assessing common complications. Careful assessment of the wall of the oesophagus should be undertaken to identify any focal regions of thickening which may indicate malignancy. The lungs should be inspected for evidence of aspiration.

Treatment is aimed at allowing adequate drainage of the oesophagus into the stomach. Options include 4-5:

  • lifestyle changes
    • eating slowly, increasing water intake with meals, avoiding eating near bedtime
    • avoiding foods that aggravate reflux
  • calcium channel blockers
    • ineffective in the long term
    • may be used while preparing for definitive treatment
  • pneumatic dilatation
    • effective in 85% of patients
    • 3-5% risk of bleeding/perforation
  • botulinum toxin injection
    • lasts only ~12 months per treatment
    • may scar the submucosa leading to increased risk of perforation during subsequent myotomy
  • surgical myotomy (e.g. Heller myotomy)
    • 10-30% of patients develop gastro-oesophageal reflux, and thus it is often combined with a fundoplication (e.g. Dor, Toupet, Nissen)
    • the use of peroral oesophageal myotomy (POEM procedure) is increasing in select patients

The word achalasia stems from the Greek term "does not relax".

A number of entities may mimic achalasia, forming the so-called 'achalasia pattern'.

Other oesophageal disorders should also be considered:

Oesophageal pathology
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Article information

rID: 835
Synonyms or Alternate Spellings:
  • Primary achalasia

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Cases and figures

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