Achalasia overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Twinkle Singh, M.B.B.S. [2], Ahmed Younes M.B.B.CH [3]
Overview
Achalasia is a primary esophageal motility disorder of unknown etiology.[1][2]In this disorder, the smooth muscle layer of the esophagus has impaired peristalsis (muscular ability to move food down the esophagus), and the lower esophageal sphincter (LES) fails to relax properly in response to swallowing due to absent enteric neurons.[3] It should be differentiated from pseudoachalasia (caused by neoplastic infiltration of myenteric neurons) and secondary achalasia (caused by extrinsic procedures such as previous fundoplication and gastric banding). Trypanosoma cruzi infection causing Chagas disease can also result in achalasia. It is an incurable chronic condition.[1]
Historical Perspective
Achalasia is Greek for failure to relax and has been known for more than 300 years BC. The first successful esophagomyotomy was done in 1913 while laparoscopic esophagomyotomy was described in 1991.
Classification
Achalasia can be classified according to the pattern of abnormal peristalsis into three types. Different types of achalasia are shown to have different responses to therapies with type II having the best prognosis.
Pathophysiology
Achalasia is caused by degeneration of myenteric neurons, resulting from immune system activation. Evidence for antigens responsible for such immune system activation still remain inconclusive, however, viral antigens such as HSV-1, HPV, measles have been shown to play a role in achalasia pathogenesis. Genetic factors such as HLA class II alleles also predispose to achalasia development.
Causes
Achalasia is chronic esophageal motility disorder. The most common form is primary achalasia, which has no known underlying cause. It is due to the failure of distal esophageal inhibitory neurons. However, a small proportion occurs secondary to other conditions, such as esophageal cancer or Chagas disease.
Differentiating Achalasia overview from Other Diseases
Achalasia must be differentiated from other causes of dysphagia, odynophagia and food regurgitation such as GERD, esophageal adenocarcinoma, esophageal stricture, esophageal webs, motor disorders such as myasthenia gravis, stroke, Zenker's diverticulum, diffuse esophageal spasm, systemic sclerosis and Plummer Vinson syndrome.
Epidemiology and Demographics
The incidence of Aachalasia is approximately ~ 1 per 100,000. There is no predilection to any age and has the same prevalence in both whites and non-whites.
Risk Factors
The most potent risk factor in the development of achalasia is Allgrove syndrome. Other risk factors include herpes infection, measles infection, autoimmune diseases, and HLA type 2.
Screening
According to the USPSTF, no screening measures are recommended for achlasia.
Natural History, Complications, and Prognosis
If left untreated, the disease can progress causing complications such as candida esophagitis and esophageal perforation. However, achalasia does not alter the lifespan of the patients. Common complications include GERD, Barrett's esophagus, and aspiration pneumonia. The prognosis is good with cure rate of 60-90% after surgical interventions.
Diagnosis
History and Symptoms
The main symptoms of achalasia are dysphagia, regurgitation of undigested food, retrosternal chest pain and weight loss. Dysphagia involves both fluids and solids and progressively worsens over time. The chest pain experienced, also known as cardiospasm and non-cardiac chest pain can often be mistaken for a heart attack. Food and liquid, including saliva, can be retained in the esophagus and may be aspirated into the lungs. Some people may also experience coughing when lying in a horizontal position.
Physical Examination
Laboratory Findings
Imaging Findings
Other Diagnostic Studies
Treatment
Medical Therapy
Surgery
Prevention
References
- ↑ 1.0 1.1 Vaezi MF, Pandolfino JE, Vela MF (2013). "ACG clinical guideline: diagnosis and management of achalasia". Am J Gastroenterol. 108 (8): 1238–49, quiz 1250. doi:10.1038/ajg.2013.196. PMID 23877351.
- ↑ Kraichely R, Farrugia G (2006). "Achalasia: physiology and etiopathogenesis". Dis Esophagus. 19 (4): 213–23. PMID 16866850.
- ↑ Park W, Vaezi M (2005). "Etiology and pathogenesis of achalasia: the current understanding". Am J Gastroenterol. 100 (6): 1404–14. PMID 15929777.