Froukje B van Hoeij, Paul Fockens, and Albert J Bredenoord
Esophageal achalasia is a primary esophageal motor disorder characterized by aperistalsis and absent relaxation of the lower esophageal sphincter (LES). The first description of the disease is credited to Sir Thomas Willis in 1674, who resolved the symptoms by using a whale bone to dilate the LES. 1 The term achalasia, later introduced by Hurst and Rake in 1929, is derived from the ancient Greek words “a” and “khalasis” translated as “not loosening.” Clinically, achalasia manifests as progressive dysphagia, retrosternal pain, regurgitation, and weight loss. The diagnosis of achalasia is made using esophageal manometry. Typical endoscopic findings are stasis of food or saliva in the esophagus, a dilated lumen, and a difficult to pass LES. But achalasia can easily be missed during upper endoscopy.
In this chapter, we discuss the endoscopic findings and the endoscopic treatment modalities. All treatment modalities in achalasia are directed at lowering the pressure of the lower esophageal sphincter to improve esophageal clearance. The most used endoscopic treatment options are botulinum toxin injections, pneumatic dilations, or a myotomy of the LES. Intrasphincteric injection of botulinum toxin type A paralyzes the LES. It has a good short-term efficacy and low complication rate, but repeat injections are usually needed. Series of graded pneumatic dilations with a low-compliant polyethylene balloon have a longer efficacy, but recurrence generally occurs in half the treated patients. The most recently introduced endoscopic therapy is the peroral endoscopic myotomy (POEM). In experienced hands, it renders a very acceptable safety and efficacy at the short and medium term.
Idiopathic or primary esophageal achalasia is a relatively rare disease with a prevalence of 10 per 100,000 individuals. The incidence has been fairly stable over the last few years, at 0.5 to 1.2 per 100,000 persons per year. The most common age of onset is around age 30 to 60 years, although an age distribution between birth and the ninth decade of life has been described. The male to female ratio is 1:1 and there is no racial predisposition. 2 General life expectancy and causes of death of achalasia patients do not differ from those of the average population.
The motility abnormalities of the esophageal smooth muscles occur as a result of degeneration of the myenteric (Auerbach’s) plexus (▶Fig. 26.1). Progressive decrease in number of ganglionic cells and neurons results in deranged inhibitory control. 3 This causes a varying degree of imbalance between inhibitory and excitatory function and concomitant contractility and abnormal LES relaxation. Besides this, as a result of chronic stasis of food and liquids, mucosal irritation of the distal esophagus occurs. Furthermore, some patients develop smooth muscle hypertrophy in the esophagus, secondary to the elevated LES pressure.
The etiology of achalasia is still not completely elucidated, but is likely to be multifactorial. There are different hypotheses on the etiology of esophageal achalasia. The most widely accepted theory is an infectious agent causing a neurodegenerative response directly or via an autoimmune response. The autoimmune theory is based on a higher prevalence of autoimmune diseases and antineural autoantibodies in achalasia patients, and the presence of T cell infiltrates within the myenteric plexus in achalasia patients. 4 , 5 The infectious agent theory is based on Chagas disease with a known infectious etiology (Trypanosoma cruzi), several reports on Guillain–Barré or varicella zoster preceding the onset of achalasia and increased titers of herpes viruses in achalasia patients. In some case series, achalasia is found to have a hereditary or degenerative cause. Furthermore, in some patients, an achalasia-like disorder occurs secondary to radiation damage, sarcoid infiltration, or a malignant invasion; this is called pseudoachalasia. 2
26.1.4 Clinical Presentation
Clinically, achalasia manifests as slowly progressive dysphagia to both liquids and solids, accompanied by retrosternal pain and regurgitation of undigested food. The Eckardt score (▶Table 26.1) is a clinical scoring system for achalasia symptoms, with a maximum score of 12. The Eckardt score is the sum of the symptom scores for dysphagia, regurgitation, chest pain, and weight loss. Patients often adapt to the slowly progressive dysphagia. 6 This patient delay is often exacerbated by a diagnostic delay due to unfamiliarity with the disease and frequent confusion with gastroesophageal reflux disease. In advanced disease, usually saliva regurgitation and weight loss are reported. In elderly patients with a short history of symptoms and significant weight loss, one should be aware of an underlying malignancy.
Weight loss (kg)
26.2 Diagnostic Approaches
26.2.1 General Approach Including Equipment and Techniques
The diagnosis is made with esophageal manometry. A barium esophagography can be very useful and provides information on esophageal emptying, luminal dilation, and shape. Sometimes endoscopic ultrasound (EUS) or computed tomography (CT) scan are used as ancillary tests.
The first step in diagnostic evaluation of a patient with dysphagia will usually be an upper gastroscopy (Video 26.1). This is essential to rule out structural abnormalities such as a stricture or malignancy. In achalasia, typical findings on endoscopy are a dilated, atonic esophagus with retained fluid and a pinpoint LES, which is difficult to pass (▶Fig. 26.2). These findings are not diagnostic, however, and have a very low sensitivity and specificity. When excessive pressure is needed to pass the LES, a neoplastic process can be suspected. Sometimes smooth muscle hypertrophy occurs secondary to the elevated LES pressure. In advanced disease, a tortuous esophagus with thickened, friable, or even ulcerated mucosa can be seen secondary to chronic stasis of food and liquids. This can ultimately result in dysplasia and squamous cell carcinoma. The documented esophageal cancer risk ranges from 0-to 33-fold higher than in healthy individuals. Megaesophagus is a relatively rare complication of inadequately treated achalasia and can ultimately require esophagectomy.
Esophageal High-Resolution Manometry
Esophageal high-resolution manometry (HRM) is currently the gold standard for diagnosing achalasia. The manometry catheter is placed transnasally and measures the esophageal pressure pattern throughout the whole esophagus. In case of achalasia, the manometry will reveal aperistalsis and poor or absent LES relaxation. Depending on the type of achalasia, absent contractility (type I), panesophageal pressurization (type II), or spastic contractions (type III) will be seen during water swallows (▶Fig. 26.3). 7
The barium esophagography can reveal absent or abnormal contractions, esophageal dilation, narrowing of the esophagogastric junction with a characteristic “bird-beak” appearance (▶Fig. 26.4), and a poor esophageal emptying of the barium into the stomach. In late stages, a severely dilated, tortuous esophagus is sometimes seen, which is called a sigmoid-shaped esophagus. Another relatively rare complication of untreated achalasia is an epiphrenic diverticulum arising just above the LES. This is usually a herniation of the mucosa and submucosa caused by chronic elevated intraluminal pressure.