Achalasia is not a common disorder in medicine. Most clinicians will not encounter a patient with this esophageal motility disorder that occurs because of the lower esophageal sphincter fails to relax. The esophagus also has a marked absence of peristalsis. In more than 50% of patients, the lower esophageal sphincter is hypertensive. This condition causes a functional obstruction at the gastroesophageal junction.
Achalasia is thought to occur from the degeneration of the myenteric plexus and vagus nerve fibers of the lower esophageal sphincter. The exact etiology of this degeneration is unclear, though many theories have been proposed. These theories include autoimmunity, infection, and genetic predisposition. Chagas disease can also cause achalasia.
One European study strongly supports the notion that achalasia may be an autoimmune disorder. The autoantibodies which have not yet been identified appear to interact with DNA, like in type 1 diabetes and lupus.
Achalasia is very rare, occurring in roughly one per 100,000 people. It does not predominantly affect a particular age or gender. However, for some unknown reason, the incidence of achalasia is increased in individuals with spinal cord injury, typically these cases are related to injury to the cervical and thoracic vertebrae.
Altered esophageal motility similar to achalasia is also observed in individuals with anorexia nervosa. There are reports of achalasia after use of endoscopic sclerotherapy for varices. The higher the number of sclerotherapy sessions, the greater the risk of achalasia. Most of these patients will show hypotensive peristalsis and defective lower esophageal sphincter function.
Outside the United States, rates of achalasia vary from 0.1 to 1 per every 100,000 people per year. Studies show that relapse rates tend to be higher if the initial treatment was pneumatic dilatation. However, complications have been noted to be much higher in patients who underwent a Heller myotomy compared to those who underwent pneumatic dilatation.
Achalasia occurs with equal frequency in both males and females. The disorder typically affects people between the second to the fifth decade of life. Overall, less than 2% to 5% of cases occur in children less than age 16.
Gradual neural degeneration directly results in exaggerated contractions of the lower esophageal sphincter and a loss of regulation. This degeneration leads to the functional obstruction which then results in dilatation. This dilatation results in an irreversible aperistalsis, as well as worsening obstructive symptoms. The reason that these changes occur is unclear.
Excitatory neurotransmitters, such as substance P and acetylcholine, and inhibitory neurotransmitters, such as vasoactive intestinal peptide and nitric oxide, modulate lower esophageal sphincter pressure and relaxation. Individuals with achalasia lack noncholinergic, nonadrenergic inhibitory ganglion cells; this lack results in an imbalance of inhibitory and excitatory neurotransmission. The end result is a nonrelaxed hypertensive esophageal sphincter.
About 50% of patients with achalasia typically present with dysphagia solids, and about 67% with liquids. Roughly half of the patients will present with chest pain as well, although the improvement of esophageal emptying does not usually alleviate the pain. As the disease progresses, patients may have symptoms of regurgitation with possible aspiration, heartburn, and weight loss from difficulty eating.
Symptoms of achalasia include vague chest discomfort, regurgitation, heartburn or nocturnal acidity, dysphagia, and weight loss. Dysphagia is the most common presenting symptom. Weight loss is often rapid because of the inability to swallow. Physical examination may reveal an emaciated individual.
The best initial test to diagnose achalasia is a barium esophagram, which may show the classic finding of tapering of the dilated esophagus to a “bird’s beak.” Esophageal manometry will reveal incomplete lower esophageal sphincter relaxation and sometimes a lack of peristalsis in the lower esophagus. Upper endoscopy should also be performed to rule out pseudoachalasia from esophageal cancer.
Recommended Courses of Action
The recommended step for reducing pressure across the lower esophageal sphincter is surgical myotomy, which can be done laparoscopically. This procedure will cut the circular muscle running across the lower esophageal sphincter, leading to relaxation. It can potentially cause uncontrolled gastric reflux, so it is typically paired with an anti-reflux procedure such as Nissen or Dor fundoplication.
An alternative to surgical myotomy at limited centers is peroral endoscopic myotomy using upper endoscopy. A less invasive option is endoscopic pneumatic balloon dilatation to tear the sphincter and relieve the obstruction. Recurrence is more common using balloon dilatation and is typically treated with repeat dilatation. However, the long-term symptom relief is equivalent when compared with myotomy.
Nonsurgical alternatives include calcium channel blockers, isosorbide dinitrate, or the direct injection of the lower esophageal sphincter with botulinum toxin. Unfortunately, symptom recurrence is much more frequent with medical therapy.
The aim of treatment is to ease the symptoms of achalasia by decreasing the outflow resistance caused by a nonrelaxing and hypertensive lower esophageal sphincter.
Pharmacologic and nonsurgical treatments include the administration of nitrates and calcium channel blockers to lower the lower esophageal sphincter pressure. This treatment is primarily for elderly patients who cannot undergo surgery or pneumatic dilatation. Another option is an injection of botulinum toxin endoscopically. The toxin is known to block the release of acetylcholine at the level of the lower esophageal sphincter. This treatment is useful in elderly patients who may not be candidates for surgery or dilatation.
Surgical treatments include a peroral endoscopic myotomy or a laparoscopic Heller myotomy. The important thing is that the fundoplication is partial, not complete. One may use the posterior (Toupet) or the anterior (Dor) partial fundoplication. The anterior fundoplication is the more common choice.
An endoscopic dilatation is the first treatment for a patient in whom surgery fails. If this also fails, the reason for the failure must be identified with imaging studies before attempting a second operation. Esophagectomy is the last resort.
When a patient presents with dysphagia, the diagnosis of a malignancy should always be entertained.
Other disorders in the differential include:
The use of pneumatic dilatation and laparoscopic myotomy can produce good results with symptom relief. Rates of esophageal perforation are rare after pneumatic dilatation, but relapses are common.
All patients who undergo treatment for achalasia need long-term follow-up because all available treatments are palliative, making recurrences common.
A thoracic surgeon and a gastroenterologist should be consulted on management.
Pneumatic dilatation and laparoscopic myotomy are effective treatments for managing achalasia. If an experienced surgeon is available, surgery is preferred.
Do not use botulinum toxin and medications if performing a pneumatic dilatation or laparoscopic Heller myotomy.