Achalasia

It is a motor disorder of the esophagus, characterized by a lack of relaxation of the lower esophageal sphincter after swallowing and by the appearance of abnormal contractions in the esophageal body instead of normal peristalsis.

Depending on these contractions, a distinction must be made between classic achalasia and vigorous achalasia, in which the contractions are longer and longer lasting. Both must be differentiated, in turn, from cricopharyngeal achalasia; in this, the lack of relaxation affects the cricopharyngeus muscle.

It affects 1 in 100,000 people a year, without distinction of sex. It can appear at any age, although it has a peak incidence between 30 and 60 years (cricopharyngeal is more common in those over 60).

Causes of achalasia

Regarding the etiology, we have to distinguish between primary achalasia, of unknown cause, and achalasia secondary to other anomalies (such as Chagas disease, cancer of the esophagus or stomach that infiltrates the esophagus, etc.).

Cricopharyngeal achalasia is sometimes associated with Zenker’s diverticulum.

Achalasia is caused by poor innervation of the esophageal smooth muscle, mainly at the cost of a reduction in the number of myenteric plexus cells (which is higher in classic achalasia).

What symptoms appear?

Classically, the symptoms of achalasia are three:

• discomfort when swallowing (dysphagia)
• regurgitation of food
• chest pain

Dysphagia is the most frequent symptom, and it occurs for both solids and liquids; it can be aggravated by fast foods or psychological stress .

Regurgitation is caused by the retention of food and saliva in the esophagus as the passage to the stomach is closed. There is a danger that these pass into the respiratory tract (especially at night, when the patient is lying down), causing coughing spells or pulmonary complications (aspiration pneumonia, etc.).

Chest pain is more severe in vigorous achalasia.
Over the months or years, weight loss, malnutrition, and anemia may appear; there is the possibility that achalasia is complicated by esophageal cancer (in 2% to 7% of cases), especially in patients who do not comply with or have not undergone treatment.

Diagnosis of achalasia

After the medical history and physical examination, which normally lead to the suspicion of the disease, we must confirm it with the following tests:

Chest X-ray, which may reflect a dilated esophagus (due to food retention), manifested by mediastinal widening. The dilation is seen more clearly by doing the barium contrast test (sigmoid esophagus or megaesophagus), which also allows to observe, in advanced cases, the lower esophageal portion with a pointed shape (called bird’s beak).

The most effective test in achalasia is manometry, which demonstrates incomplete relaxation of the lower esophageal sphincter after swallowing and the appearance of abnormal contractions in the body of the esophagus during swallowing.

Poor esophageal innervation produces hypersensitivity to stimulation; administration of cholecystokinin causes a contraction of the lower esophageal sphincter (normally dilates it).

An endoscopy is also necessary to assess the state of the esophageal mucosa and to rule out possible causes of secondary achalasia.

Treatment

There is no treatment that restores the motor function of the esophagus, so in this case, what is tried is to restore the passage from the esophagus to the stomach.

The best treatment for achalasia is dilation of the lower esophageal sphincter using an inflatable balloon, although this procedure can be complicated by perforation of the esophagus and bleeding.

Drug treatment is not very successful in this disease, and it is only used in patients who cannot be given another (such as children or the elderly). It consists of nitrates and calcium channel antagonists (especially nifedipine).

Today, the injection of botulinum toxin into the lower esophageal sphincter has appeared as a novelty, but it is still under experimentation (it seems to be more effective in cases of vigorous achalasia and in the elderly).

Surgical treatment is practiced in people in whom sphincter dilation is not indicated or has not been successful. This mainly consists of a technique called Heller’s extramucosal myotomy (in which the sphincter is cut, and which has been modified in recent years so that the cut is only anterior). It must be completed with a gastroesophageal antireflux technique, a frequent complication of surgery, as the passage between esophagus and stomach is open.

As a last option, there is the total resection of the esophagus and its replacement with a tubulized stomach (tube-shaped).

For cricopharyngeal achalasia, the final treatment is cricopharyngeal myotomy, a technique that is contraindicated in the presence of gastroesophageal reflux.