Pathogenesis and morphological changes
The disease is based on damage to the nervous system, specifically impairment of cholinergic innervation. Because of this, the lower esophageal sphincter (LES) loses its ability to adequately reflexively relax, and its resting tone increases significantly. An additional factor in endemic areas (South America) is infection with Trypanosoma cruzi, which causes Chagas disease.
Persistent LES spasm leads to severe changes. Normal food passage is disrupted, and food accumulates above the sphincter. As a result, the proximal parts of the esophagus become severely dilated, forming the so-called megaesophagus. The walls of the esophagus themselves lose their normal contractile ability.
Clinical presentation
The disease is characterized by a long asymptomatic period. Occasionally, a sudden onset of pronounced dysphagia occurs, which is often triggered by emotional stress.
Main symptoms:
- Dysphagia is a swallowing disorder of a slowly progressive nature.
- Pain syndrome includes retrosternal pain and regurgitation occurring directly during meals.
- Weight loss — due to impaired nutrition, weight loss is observed in 90% of patients.
Stagnation of contents in the dilated esophagus poses a risk of complications. Regurgitation of undigested food eaten several hours prior occurs. Inhalation of stagnant food masses (aspiration) carries a high risk of aspiration pneumonia.
Diagnostics
A set of instrumental methods is used to confirm the diagnosis:
- Barium swallow X-ray examination. Shows esophageal dilation with a fluid level (a clear border with air is visible) and narrowing in the distal part. Contrast is evacuated into the stomach with difficulty. Important signs include the absence of the gastric air bubble and impaired peristalsis (up to diffuse spasm). Important: the X-ray picture can mimic gastric cardia cancer.
- Esophagogastroduodenoscopy (EGD). Mandatory for differential diagnosis. Performed with a biopsy to reliably rule out a malignant process.
- Esophageal manometry. Allows recording the absence or incomplete reflexive relaxation of the LES during swallowing, and also reveals hyperkinesia of the esophageal walls.
Treatment
Therapy is aimed at reducing LES tone and improving food passage.
- Conservative therapy. Used for medical relief of muscle spasm. Patients are prescribed nitrates and calcium channel blockers.
- Instrumental and surgical methods. These include balloon dilation (mechanical expansion of the sphincter) and surgical myotomy (dissection of the sphincter muscle fibers). These methods are effective in 75% of cases.
However, surgical interventions can have consequences. Potential complications include the development of reflux esophagitis, stricture formation, recurrence of achalasia, and an increased risk of esophageal cancer.
Briefly: answers to topical questions
What types of achalasia are distinguished according to the Chicago classification based on high-resolution manometry data?
According to the Chicago classification, there are three types of achalasia cardiae, differing in peristaltic activity.
- Type I — complete absence of peristalsis in the thoracic esophagus and no simultaneous increase in esophageal pressure.
- Type II — complete absence of peristalsis, however, simultaneous increase in esophageal pressure is detected in 20% or more of swallows.
- Type III — complete absence of peristalsis, with potential simultaneous pressure increases, as well as spastic or premature contractions recorded in 20% or more of swallows.
What diseases and conditions, apart from Chagas disease, can cause secondary achalasia (pseudoachalasia)?
The cause of secondary achalasia (pseudoachalasia) is malignant neoplasms of the esophagogastric junction or adjacent organs. These include:
- pancreatic cancer;
- breast cancer;
- lung cancer;
- hepatocellular carcinoma;
- gastroesophageal junction cancer: the tumor invades the area of the esophagogastric junction and cardia, which can lead to impaired LES relaxation, esophageal dilation, and absence of peristalsis.
Class and exam questions
What is megaesophagus?
This is a significant pathological dilation of the proximal parts of the esophagus that forms due to constant impairment of food passage through the spastic lower esophageal sphincter.
Why is EGD with biopsy mandatory when achalasia is suspected?
The clinical and X-ray picture of achalasia cardiae can very precisely mimic gastric cardia cancer. EGD with biopsy is necessary for differential diagnosis and to rule out a malignant process.
What pulmonary complications can achalasia lead to?
Obstruction of the lower esophageal sphincter leads to stasis and regurgitation of ingested food. Aspiration of this stagnant content into the respiratory tract carries a high risk of developing severe aspiration pneumonia.
What else to study on this topic
- Mechanisms of esophageal cholinergic innervation
- Differential diagnosis with gastric cardia cancer
- Chagas disease (Trypanosoma cruzi infection) and gastrointestinal lesions
- Technique and interpretation of esophageal manometry
- Complications of surgical treatment: reflux esophagitis and strictures
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