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Achalasia

Achalasia is a disorder where the lower esophageal sphincter (LES) fails to relax due to the loss of inhibitory neurons in the esophageal wall. It can be primary (idiopathic) or secondary (related to another condition). Symptoms typically include difficulty swallowing (dysphagia) of both solids and liquids, regurgitation, chest pain, and weight loss. Diagnosis involves a combination of upper endoscopy, a barium swallow study of the esophagus, and esophageal manometry. Initially, an upper endoscopy or barium swallow is performed, but manometry is key for confirming the diagnosis. An upper endoscopy is also crucial to exclude any malignant causes.

Treatment options depend on the patient’s suitability for surgery. Pneumatic dilation or myotomy are preferred for those who are good surgical candidates. For others, botulinum toxin injections are often tried. If these interventions are unsuccessful, medical therapies like nifedipine may be used.

Last updated: February 20, 2024 128 views

  • Esophageal motility disorder characterized by inadequate relaxation of the lower esophageal sphincter (LES) and nonperistaltic contractions in the distal two-thirds of the esophagus due to the degeneration of inhibitory neurons
  • It is the most common esophageal motility disorder
  • Most commonly occurs in middle-aged individuals (25–60 years of age)
  • Condition is characterized by:
    • Impaired relaxation of the lower esophageal sphincter (LES)
    • Absence of normal esophageal peristalsis

  • Primary achalasia (most common): cause is unknown
  • Secondary (also called pseudo-achalasia):
    • Caused by diseases that lead to esophageal abnormalities, similar to primary achalasia
    • Malignancy (esophageal, gastric, or other extraesophageal cancers) by mass effect or as part of paraneoplastic syndrome
    • Chagas disease
      • Infection with the parasite, Trypanosoma cruzi
      • Commonly found in South and Central America
    • Infiltrative disorders: amyloidosis, sarcoidosis
    • Genetic diseases: neurofibromatosis, multiple endocrine neoplasia type 2B, Fabry's disease
    • Others: eosinophilic esophagitis, juvenile Sjögren's syndrome, chronic idiopathic intestinal pseudo-obstruction

  • In achalasia, the pathophysiology involves the dysregulation of neurohumoral control during swallowing, mediated by both excitatory (such as acetylcholine and substance P) and inhibitory (nitric oxide [NO], vasoactive intestinal peptide [VIP]) neurotransmitters.
  • The disease is characterized by the degeneration of inhibitory neurons within the myenteric (Auerbach) plexus, leading to a deficit of inhibitory neurotransmitters like NO and VIP. This neuronal loss results in the failure of the lower esophageal sphincter (LES) to relax and an increase in its resting pressure. Concurrently, there is a disruption in esophageal peristalsis. These alterations culminate in the dilation of the esophagus proximal to the LES.

  • Dysphagia (to solids and liquids): Caused by the failure of the lower esophageal sphincter (LES) to relax and the lack of normal esophageal peristalsis, leading to difficulty in swallowing.
    • Progressive Dysphagia: Typically worsens over time as the esophagus dilates and loses function.
    • Paradoxical Dysphagia: More trouble swallowing liquids than solids due to the lack of peristalsis, which is more essential for moving liquids.
  • Regurgitation: Occurs as food and gastric contents cannot pass into the stomach due to LES dysfunction, leading to their accumulation and eventual return up the esophagus.
  • Retrosternal Pain and Cramps: Arises from the esophageal distension and impaired peristalsis, causing discomfort or spasmodic pain behind the breastbone.
  • Weight Loss: A consequence of reduced food intake and nutritional absorption due to dysphagia and regurgitation, leading to a decrease in overall calorie consumption.

 

Note  
Achalasia typically manifests with progressive dysphagia to solids and liquids while esophageal obstruction manifests with dysphagia to solids only. ملاحظة

  • Pulmonary complications (e.g., pneumonia, abscess, asthma) caused by aspiration
  • Megaesophagus in 10% of cases
  • Increased risk of esophageal cancer.

  • Initial Approach:
    • Upper Endoscopy and/or Esophageal Barium Swallow:
      • First-line tests to support the diagnosis of achalasia.
      • Upper Endoscopy: Also excludes pseudoachalasia, such as obstructions due to malignancy. May reveal retained food or increased resistance at LES.
      • Esophageal Barium Swallow (Esophagram):
        • "Bird-beak" sign: Narrowing at the gastroesophageal junction with proximal dilation.
        • Delayed or retained barium, indicating impaired esophageal emptying.
  • Confirmatory Testing:
    • Esophageal Manometry:
      • Gold standard for confirming achalasia.
      • Shows absent or uncoordinated peristalsis in the distal esophagus.
      • Incomplete or absent LES relaxation.
      • High resting pressure of the LES.
      • No mechanical obstruction.
  • Additional Diagnostic Steps:
    • If manometry is inconclusive and barium swallow was not initially performed, an esophagram can confirm the diagnosis.
    • If malignancy is suspected during endoscopy, further assessment with biopsy and endoscopic ultrasound is necessary.
  • Chest X-Ray (less commonly used but can show):
    • Widened mediastinum.
    • Air-fluid level in lateral view.
    • Potential absence of gastric air bubble.

  • For Patients with Low Surgical Risk:
    • Pneumatic Dilation:
      • Endoscopic balloon dilation of the LES, tearing muscle fibers to alleviate obstruction.
      • Approximately 85% success rate at one month; around 2% risk of perforation.
    • LES Myotomy (Heller Myotomy):
      • Surgical incision of the LES to facilitate passage of food to the stomach.
      • Often combined with anti-reflux surgery (like fundoplication) to prevent postoperative GERD.
      • Particularly recommended for younger patients.
    • Peroral Endoscopic Myotomy (POEM):
      • Endoscopic myotomy targeting the inner circular layer of the LES, preserving the longitudinal layer.
      • Can also be used for other esophageal motility disorders, possibly requiring extension into the esophageal body.
  • For Patients with High Surgical Risk:
    • Botulinum Toxin Injection in the LES:
      • Suitable for patients not eligible for surgery.
      • Over 50% may require retreatment within 6–12 months.
    • Pharmacotherapy (if other measures fail):
      • Nitrates or calcium channel blockers.

Achalasia

Pathophysiology
  • Inflammatory degeneration of inhibitory ganglions of the myenteric plexus

Clinical
presentation
  • Chronic dysphagia to solids & liquids, regurgitation
  • Heartburn, weight loss

Diagnosis
  • Manometry: incomplete LES relaxation, ↓ peristalsis of distal esophagus
  • Barium esophagography: smooth "bird-beak" narrowing at gastroesophageal junction
  • Upper endoscopy to exclude malignancy

Management
  • Myotomy or pneumatic balloon dilation
  • Botulinum toxin injection, nitrates & CCB

CCB = calcium channel blocker; LES = lower esophageal sphincter.
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