Achalasia

Background/Epidemiology

  • Primary oesophageal motility disorder characterised by the absence of oesophageal peristalsis and impairment of lower oesophageal sphincter relaxation.
  • Rare- affects 1 in 100000 per year
  • Infection with Trypansoma cruzi which causes Chagas' disease causes a syndrome clinically indistinguishable from achalasia

Pathophysiology

  • The lower oesophageal sphincter is regulated by excitatory (e.g. acetylcholine, substance P) and inhibitory (e.g. NO, vasoactive intestinal peptide) neurotransmitters
    • In achalasia, there seems to be a lack of nonadrenergic, noncholinergic, inhibitory ganglion cells (cholinergic activity is preserved), possibly as a result of an inflammatory process
    • the result is a chronically non-relaxing LOS

Presentation

  • Most commonly- dysphagia
    • Affecting solid foods more than soft more than liquids
    • Develops gradually, commonly intermittent
    • Can be eased by drinking fluids, by standing up/moving about etc
  • Regurgitation and dyspepsia are also common.  Chest pain may occur due to oesophageal spasm, but heartburn is rare (LOS tone is increased so acid is unlikely to reflux)
  • Later in the disease, aspiration can be common (nocturnal pulmonary aspiration)

Investigations

  • Barium swallow is usually performed before endoscopy (for risk of rupture)
    • Classic dilated oesophagus which is tapered distally (said to resemble a bird’s beak); only a small amount of contrast is able to pass through into the stomach
    • Acha
  • Manometry
    • Gold standard
    • Diagnostic features include high resting pressure of the LOS, incomplete relaxation on swallowing and absent peristalsis
    • Without any features on manometry, diagnosis is instead ‘pseudoachalasia’
      • Consider other causes e.g. malignancy, strictures
  • Endoscopy may be useful in evaluating causes of pseudoachalasia but is not necessarily required for true achalasia

Management

  • Surgical myotomy is preferred if the patient is fit enough
    • requires fundoplication at the same time to avoid serious reflux disease post-operatively
    • PPIs are often prescribed post-operatively for this reason also
  • For older patients/patient not suitable for general anaesthetic etc, endoscopic pneumatic dilation may be used
  • Endoscopic botox injection is rarely used.  Other medical options include calcium channel blockers and nitrates but these are rarely successful
  • NB Endoscopic myotomy methods are now beginning to be used

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