- Clinical science
Achalasia is a failure of the lower esophageal sphincter (LES) to relax that is caused by the degeneration of inhibitory neurons within the esophageal wall. It is classified as either primary (idiopathic) or secondary (in the context of another disease). In patients with achalasia, the chief complaint is dysphagia to both solids and liquids, although regurgitation, retrosternal pain, and weight loss may also occur. Upper endoscopy, barium esophagram, and esophageal manometry play complementary roles in the diagnosis of achalasia. While upper endoscopy and/or barium esophagram are often obtained initially, manometry usually confirms the diagnosis, and upper endoscopy is indicated to rule out a malignant underlying cause. In good surgical candidates, achalasia is usually treated with pneumatic dilation or myotomy. In most other cases, an injection of botulinum toxin is attempted. If these measures fail to provide relief, medical therapy (e.g., nifedipine) is indicated.
- Rare disorder (∼ 1.6/100,000 individuals)
- Most commonly occurs in middle-aged individuals
Epidemiological data refers to the US, unless otherwise specified.
- Primary achalasia (most common): cause is unknown
- Secondary achalasia (pseudoachalasia): The presentation and manometric findings of a mechanical cause of obstruction (e.g., a malignancy) that mimics achalasia.
- Swallowing is controlled through excitatory (acetylcholine, substance P) and inhibitory (NO, VIP) neurohumoral substances.
- Degeneration of inhibitory neurons within the myenteric plexuses (Auerbach's plexus) → deficient inhibitory neurotransmitters → failure to relax and higher resting pressure of the LES, as well as dysfunctional peristalsis → esophageal dilation proximal to LES
- In general, all patients with suspected achalasia should initially undergo upper endoscopy and/ or barium esophagram; findings may support the diagnosis.
- Esophageal manometry is indicated to establish the diagnosis (confirmatory test of choice), irrespective of the initial imaging findings.
- If manometry is inconclusive and a barium esophagram was not obtained initially, esophagram can also play a confirmatory role.
- Endoscopy should be performed to rule out pseudoachalasia because the presentation and manometric findings of a mechanical cause of obstruction (e.g., a malignancy) may mimic achalasia.
- Barium esophagram: supportive and/or confirmatory test
Upper endoscopy: to rule out pseudoachalasia
- Usually normal
- May show retained food in esophagus or increased resistance of LES during passage with endoscope
- If malignancy is suspected, biopsy and endoscopic ultrasound are indicated
Esophageal manometry: confirmatory test of choice
- Lack of peristalsis in the lower two-thirds of the esophagus
- Incomplete or absent relaxation of the LES
- Increased resting pressure
- No evidence of mechanical obstruction
- Chest x-ray
Differential diagnosis of esophageal motility disorders
Esophageal motility disorders range from hypomotile dysfunction (achalasia) to hypermotile dysfunction (diffuse esophageal spasm, nutcracker esophagus); of the esophagus. They have similar symptoms with dysphagia, chest pain, and regurgitation of food, but are differentiated based on findings in esophagograms and esophageal manometry.
Lower esophageal sphincter (LES) pressure and relaxation
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The differential diagnoses listed here are not exhaustive.
If a low surgical risk
The preferred treatment often depends on the surgeon and the patient's situation. However, attempting pneumatic dilation before myotomy is gaining popularity because it is less invasive and the time of recovery is faster. This approach is already more popular in Europe.
- Pneumatic dilation
- Endoscope-guided graded dilation of the LES that tears the surrounding muscle fibers with the help of a balloon
- The success rate at one month is ∼ 85%; perforation risk is ∼ 2%.
- LES myotomy (Heller myotomy)
If a high surgical risk
Botulinum toxin injection in the LES
- A good choice for patients who are poor surgical candidates
- More than 50% of patients require treatment again within 6–12 months.
- If other measures are unsuccessful: nifedipine or calcium channel blockers