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Achalasia


Definition

  • Form of esophageal dysmotility characterized by loss of distal esophageal peristalsis and failure of lower esophageal sphincter relaxation 

Etiology & Pathophysiology 

  • Usually idiopathic in origin
    • Degeneration of neurons within the myenteric plexus of the
      esophageal smooth muscle
  • Neuronal destruction is typically inflammatory in nature
    • Histologically: lymphocytic infiltrate surrounding the plexus
    • Predominantly involves the nitric-oxide producing inhibitory neurons
      • Cause smooth muscle relaxation by inhibiting the acetylcholine
        producing excitatory neurons
  • Loss of inhibitory input results in unopposed contractile stimulation and
    aperistalsis
    • Acetylcholine producing neurons (which stimulate smooth muscle
      contraction) are relatively spared in this degenerative process
       

Types

  • Primary achalasia (idiopathic)
    • Unknown cause of inflammatory neuronal degeneration
  • Secondary achalasia (pseudoachalasia)
    • Recognized pathologic causes of esophageal motility disorders often indistinguishable from primary achalasia
      • Malignancy (especially gastric cancer)
      • MEN, Type 2B
      • Chagas’ disease
      • Juvenile Sjögren’s
      • Amyloidosis
      • Chronic idiopathic intestinal
      • Sarcoidosis
      • Pseudo-obstruction
      • Neurofibromatosis
      • Eosinophilic gastroenteritis
      • Fabry’s disease
      • Scleroderma 

Epidemiology

  • Annual incidence of 1 case per 100,000
  • Men and women affected equally
  • Occurs at any age
    • Typically between 25-60 years of age
      • Onset rare before adolescence 

Clinical Findings

  • Dysphagia for solids and liquids predominate (85-95% of patients)
    • Dysphagia for liquids especially should prompt evaluation for achalasia
  • Difficulty belching
  • Hiccups
  • Weight loss
  • Chest pain
    • Usually secondary to failure of LES relaxation
    • More common in younger patients and tends to regress
  • Regurgitation of retained material in esophagus, especially upon lying down
    • May lead to recurrent aspiration
  • Heartburn in 40-60%
    • Tend to have lower LES pressures than those without GERD
  • Increased incidence of esophageal cancer
    • Usually squamous cell
    • Surveillance endoscopy not recommended (usually seen 15-20 years after development of achalasia) 

Imaging Findings

  • Barium studies
    • 95% diagnostic accuracy
    • Early/Stage I
      • Primary peristaltic waves absent with abnormal distal peristalsis
      • Only minimal narrowing of the GE junction
      • Occasionally may see nonpropulsive peristaltic waves in the esophageal body (“vigorous achalasia” secondary to tertiary waves)
    • Progressive disease
      • “Bird’s beak” appearance of GE junction
        • Distal esophagus makes right angle before entering stomach
    • Hurst phenomenon
      • With the patient upright, barium builds up to a point where the
        hydrostatic pressure of the barium overcomes the LES pressure
        • Occasional “spurt” of barium through the GE junction as it is intermittently  forced open
      • Dilated, aperistaltic esophageal body; may assume a sigmoid shape
    • Severe disease
      • Significant esophageal body dilation with large amounts of fluid/food retention
      • Entire esophagus atonic in late stages 
  • Chest x-ray
    • With severe disease, may readily see the large, dilated esophagus
      with air fluid level at the aortic arch or above
    • Stomach bubble frequently absent 
  • CT Scan
    • Not typically used for diagnosis
    • Seen as dilated luminal structure with retained debris and narrowing
      at level where it enters the stomach
       
  • Manometry
    • Usually required for confirmation of diagnosis
      • Elevated resting LES pressure
      • Incomplete LES relaxation
      • Absence of peristalsis 
  • Endoscopy
    • Must rule out malignancy
    • Reveals dilated esophagus with normal mucosa
    • Retained fluid/food
    • Possible Candidal infection secondary to esophageal stasis
    • Endoscope should pass easily through LES with gentle pressure applied
      • Unlike strictures caused by neoplasms, fibrosis etc 

Differential Diagnosis

  • Reflux esophagitis with stricture
    • Narrowing is usually higher than the EG junction
    • Normal esophageal peristalsis
  • Carcinoma
    • Only minimal dilation with normal peristalsis
  • Scleroderma
    • Barium should empty when patient is upright
    • Other associated GI abnormalities
  • Chagas disease
    • Not distinguishable by x-ray; history needed 

Treatment

  • Medical therapy
    • Nitrates, calcium channel blockers (nifedipine)
      • Cause smooth muscle relaxation but with limited success
  • Pneumatic dilation of the LES
    • Tears muscle fibers of LES, thus weakening it
    • Varying protocols regarding type and diameter of dilator,
      balloon inflation pressure and rate at which it is inflated, duration of
      inflation, and number of inflations per session
    • Good short-term results, but many patients require further intervention,
      with successive dilations adding little benefit
      • Potential complications of esophageal perforation (2-6%) and GERD
  • Surgical myotomy
    • LES muscle fibers cut
    • Laparoscopy becoming more popular
    • Good relief of symptoms in majority of patients with complication rate
      similar to that of dilation
    • Superior method for achieving better long term results
    • Debate as to whether fundoplication is necessary to prevent
      longstanding GERD
  • Botulinum toxin injection
    • Inhibits release of excitatory acetylcholine from nerve endings
      (thus causing lower LES pressures)
    • Good short­-term results, but long term efficacy unknown

Achalasia

Achalasia

Achalasia. Upper: There is a large air-filled tubular structure that represents the dilated esophagus (white arrows). Lower: An esophagram shows a massively dilated esophagus (yellow arrows) down to the esophagogastric junction consistent with achalasia.
For these same photos without the arrows, click
here and here

 

achalasia

CT scan of the chest demonstrates a markedly dilated esophagus

containing barium, debris and a fluid level

achalasia


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