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Gastrointestinal (GI) System

Achalasia

Neurodegenerative motility disorder of the oesophagus resulting in deranged oesophageal peristalsis and loss of lower oesophageal sphincter function.

Neurodegenerative motility disorder of the oesophagus resulting in deranged oesophageal peristalsis and loss of lower oesophageal sphincter function.

  • Functional obstruction at the gastroesophageal junction.
  • M/C cause of dysphagia

Etiology

Risk factors:

  • Auto-immune conditions: Sjogren’s syndrome, Systemic Lupus Erythematosus and uveitis
  • Infectious agents: Chagas disease, varicella zoster virus and Guillain-Barre syndrome
  • Genetic associations:
    • Triple “A” syndrome: Triad of achalasia, alacrima and adrenocorticotrophic hormone resistant adrenal insufficiency
    • Parkinson’s disease
    • Downs syndrome
    • MEN2B syndrome
Proposed model for the development of achalasia
Proposed model for the development of achalasia. Some people with genetic predisposition (HLA class II susceptibility, gene mutations, or certain SNPs) have a viral trigger (herpes simplex virus 1, varicella zoster, or measles) that leads to aggressive inflammatory response. Interactions between T-cell–mediated inflammatory infiltrate, extracellular matrix turnover proteins, and development of humoral response (myenteric antibodies) lead to apoptosis of ganglionic neurons. These events subsequently lead to myenteric plexitis and fibrosis, resulting in impaired relaxation of the LES and absence of esophageal peristalsis. | HLA, human leukocyte antigen; LES, lower esophageal sphincter; SNP, single nucleotide polymorphism. | Patel, D. A., Lappas, B. M., & Vaezi, M. F. (2017). An Overview of Achalasia and Its Subtypes. Gastroenterology & hepatology, 13(7), 411–421.

Pathophysiology

Inflammatory changes within the oesophagus following the causative insult result in the loss of postganglionic inhibitory neurons in the myenteric plexus and a consequent reduction in the inhibitory transmitters, nitric oxide and vasoactive intestinal peptide. The excitatory neurons remain unaffected, with the resulting imbalance between excitatory and inhibitory neurons preventing lower oesophageal sphincter relaxation.

Achalasia cardia pathophysiology
(A) Esophageal motor innervation by the vagus nerve; Auerbach’s and Meissner’s plexuses. (B) The striated muscle of the proximal esophagus is directly innervated by the somatic efferent cholinergic fibers of the vagus nerve originating from the nucleus ambiguus. In contrast, the smooth muscle of the distal esophagus is innervated by the preganglionic vagus nerve fibers from the dorsal motor nucleus. The preganglionic vagus fibers release acetylcholine, a neurotransmitter that affects two types of postganglionic neurons in the myenteric plexus, the excitatory cholinergic neurons and the inhibitory nitrinergic neurons. | NO, nitric oxide; VIP, vasoactive intestinal polypeptide. | Ates, F., & Vaezi, M. F. (2015). The Pathogenesis and Management of Achalasia: Current Status and Future Directions. Gut and Liver, 9(4), 449–463. https://doi.org/10.5009/gnl14446

Presentation

Early stages:

Due to initial non-specific symptoms in early stage disease and the low prevalence of achalasia worldwide, the condition often goes undiagnosed for many years, giving rise to features of late stage disease and their associated complications.
  • Similar to that of gastro-oesophageal reflux:
    • Retrosternal chest pain typically after eating
    • Heartburn

Progressive dysphagia (Cardinal sign):

Lack of peristalsis and a non-relaxing lower oesophageal sphincter

Late (established) disease:

  • Regurgitation, particularly at night, with aspiration of undigested food
  • Weight loss
Achalasia pathogenesis and clinical findings
The Calgary Guide | http://calgaryguide.ucalgary.ca/

Complications:

  • Result of the natural course of the condition:
    • Aspiration pneumonia
  • Cancer:
    • Squamous cell carcinoma (SCC): M/C oesophageal cancer in patients with achalasia
    • Oesophageal adenocarcinoma

Diagnosis

High resolution manometry with pressure topography plotting:

gold standard in diagnosis of achalasia, classically showing aperistalsis and failure of relaxation of the lower oesophageal sphincter

Uncoordinated/absent peristalsis + ↑ LES resting pressure

Oesophageal manometry demonstrating simultaneous contractions within the oesophagus and a non-relaxing lower oesophageal sphincter
Oesophageal manometry demonstrating simultaneous contractions within the oesophagus and a non-relaxing lower oesophageal sphincter. | O’Neill, O. M., Johnston, B. T., & Coleman, H. G. (2013). Achalasia: a review of clinical diagnosis, epidemiology, treatment and outcomes. World journal of gastroenterology, 19(35), 5806–5812. https://doi.org/10.3748/wjg.v19.i35.5806

Chicago classification:

  • Type I (classic): Minimal contractility in the esophageal body
  • Type II: Achalasia with intermittent panesophageal pressurization
  • Type III (spastic): Premature/spastic distal esophageal contractions
Manometric types of achalasia
Manometric types of achalasia | Type I is characterised by absence of distal pressurisation to greater than 30 mm Hg. In type II, pressurisation to greater than 30 mm Hg occurs in at least two of ten test swallows, whereas patients with type III disease have spastic contractions with or without periods of compartmentalised pressurisation. | Boeckxstaens, G. E., Zaninotto, G. and Richter, J. E. (2017) ‘Achalasia’, The Lancet. Elsevier, 383(9911), pp. 83–93. doi: 10.1016/S0140-6736(13)60651-0.

Barium esophagogram:

Not accurate in diagnosis but necessary to exclude a carcinoma at the lower end of the oesophagus
  • Bird’s beak appearance (pathognomonic) of the distal oesophagus with dilatation of the oesophagus proximally
Barium swallow demonstrating typical “bird’s-beak” appearance of the lower oesophageal sphincter in achalasia
Barium swallow demonstrating typical “bird’s-beak” appearance of the lower oesophageal sphincter in achalasia. The oesophagus above this is dilated. | Ates, F., & Vaezi, M. F. (2015). The Pathogenesis and Management of Achalasia: Current Status and Future Directions. Gut and Liver, 9(4), 449–463. https://doi.org/10.5009/gnl14446

Upper GI endoscopy:

Endoscopic appearance of achalasia
Endoscopic appearance of achalasia: (A) foam in the esophagus is often suggestive of poor motility and when combined with retained liquid (B) and food (C) along with a puckered gastroesophageal junction (D), should alert the endoscopist to the diagnosis of achalasia. | Ates, F., & Vaezi, M. F. (2015). The Pathogenesis and Management of Achalasia: Current Status and Future Directions. Gut and Liver, 9(4), 449–463. https://doi.org/10.5009/gnl14446

Other imaging modalities:



Management

There is no cure for achalasia. Thus, treatment is aimed at relieving symptoms by improving LES physiology, which leads to reduced functional obstructions and facilitates esophageal emptying. This may be achieved through pharmacologic, endoscopic, or surgical methods.

Proposed treatment algorithm for patients with
A proposed treatment algorithm for patients with achalasia. POEM, PD, or HM can be considered in all patients with achalasia who have low surgical risk, but POEM and HM might be preferable in patients younger than 40 years who have type III achalasia. | EGD, esophagogastroduodenoscopy; HM, Heller myotomy; HRM, high-resolution manometry; PD, pneumatic dilation; POEM, peroral endoscopic myotomy. | Patel, D. A., Lappas, B. M., & Vaezi, M. F. (2017). An Overview of Achalasia and Its Subtypes. Gastroenterology & hepatology, 13(7), 411–421.

Endoscopic management (1st line):

  • POEM (Per Oral Endoscopic Myotomy)
  • Gradual pneumodilation (balloon dilatation): Balloon positioned across LES and inflated, effectively rupturing the muscle of the affected segment.

Heller’s surgical myotomy:

Creating a longitudinal division of the circular muscle of the lower oesophageal sphincter, extending this both proximally and distally onto the cardia. Laparoscopic technique commonly performed

Partial posterior fundoplication following cardiomyotomy

  • Anti-reflux procedure: For treating GERD following surgery

Medical management:

Not effective long-term
  • Nitrates
  • CCF

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