Achalasia

Snapshot

• A 41-year-old man presents to the clinic complaning of substernal chest pain and regurgitation of undigested food. He also reports having difficulty swallowing both solid and liquids. A barium esophgram demonstrates a dilated proximal esophagus with a narrow tapering. 

Introduction

• Motor disorder of the distal esophagus secondary to progressive degeneration of the Aurbach plexus (ganglion cells in the myenteric plexus) 
• Epidemiology
  • incidence of 1.6 cases per 100,000 individuals
  • demographics
    • occurs equally among men and women
    • diagnosis occurs between ages of 25 and 60 years
  • risk factors
    • Chagas disease
    • other diseases such as scleroderma (see etiology)
• Etiology
  • the etiology of primary/idiopathic achalasia is unknown
  • secondary achalasia occurs due to diseases that cause esophageal motor abnormalities 
    • Chagas disease: protozoan parasite Trypanosoma cruzi destroys intramural ganglion cells
    • other diseases include amyloidosis, sarcoidosis, scleroderma, neurofibromatosis, Fabry disease, and eosinophilic esophagitis.
• Pathogenesis
  • inflammation and degeneration of neurons of the Aurbach’s plexus
    • the cause of the degeneration is unknown but may be autoimmune as suggested by the association with variants in the HLA-DQ regions in affected patients and the presence of antibodies to enteric neurons
  • primarily leads to loss of nitric oxide-producing, inhibitory neurons that affect the relaxation of esophageal smooth muscle
    • results in loss of normal relaxation of the lower esophageal sphincter (LES)  and rise in basal sphincter pressure
    • results in aperistalsis
• Prognosis
• disease is progressive without treatment that ultimately leads to end-stage achalasia characterized by esophageal tortuosity, angulation, and megaesophagus (diameter >6 cm)

Presentation

• Symptoms 
  • dysphagia for solids and liquids  
  • regurgitation  
  • difficulty belching 
  • vomit 
  • heartburn/substernal chest pain  
• weight loss  

Imaging

• Radiography 
  • may demonstrate mediastinal widening  
• Barium esophagram  
  • not a sensitive test for achalasia, as it may be interpreted as normal in up to 1/3 of patients  
  • positive findings include 1) dilation of the proximal esophagus 2) “bird-beak” appearance at the esophageal sphincter 3) aperistalsis 4) delayed emptying of barium  
• Upper endoscopy 
  • may reveal dilated esophagus that contains residual material  
  • esophageal mucosa usually appears normal  
  • often performed after esophageal manometry to rule out malignancy  
• Esophageal manometry  
  • gold standard – required to establish diagnosis
  • high-resolution manometry (vs. conventional manometry) allows for categorization of the achalasia subtype, which can guide management
• findings include increased LES pressure, inability of the LES to relax, decreased peristalsis, and diffuse esophageal spasm

Differential

• Gastroesophageal reflux disease (GERD)
  • distinguishing factor
    • regurgitated food is typically sour tasting in GERD due to the presence of gastric acid
    • will have nonspecific findings on manometry
• Pseudoachalasia due to malignancy
  • distinguishing factor
    • may have the same manometry findings but can be differentiated from achalasia via upper endoscopy
• Cardiovascular dysphagia 
  • distinguishing factor
    • compression of the anterior esophagus by enlarged left atrium of the heart
• normal manometry findings

Treatment

• Medical management
  • Botulism toxin injections
    • High initial success but have more frequent relapses and a shorter time to relapse compared to operative treatments
    • often second-line therapy offered to patients who are high risk for complications  
  • pharmacological treatments (e.g., nifedipine, nitrates, or calcium channel blockers) are often ineffective and are limited by side effects
    • indicated in patients who fail treatment with botulism toxin
• Operative
  • preferred option for patients who have average surgical risk though the efficacy of treatments decreases over time
    • 1/3 to ½ of patients will require repeat treatment within 10 years
  • endoscopic balloon dilation of LES
    • Cure rate of 80%
    • Complication of perforation in <3% of patients
  • myotomy with fundoplication
    • Similar outcomes to that of dilation
  • peroral endoscopic myotomy (POEM)
• new endoscopic technique that allows for myotomy of more proximal esophageal muscle

Complications

• Esophageal carcinoma
  • ↑ risk of esophageal squamous cell carcinoma secondary to chronic irritation from food stasis
• ulceration and bleeding