An Overview of Achalasia and Its Subtypes

Abstract

Achalasia is one of the most studied esophageal motility disorders. However, the pathophysiology and reasons that patients develop achalasia are still unclear. Patients often present with dysphagia to solids and liquids, regurgitation, and varying degrees of weight loss. There is significant latency prior to diagnosis, which can have nutritional implications. The diagnosis is suspected based on clinical history and confirmed by esophageal high-resolution manometry testing. Esophagogastroduodenoscopy is necessary to rule out potential malignancy that can mimic achalasia. Recent data presented in abstract form suggest that patients with type II achalasia may be most likely, and patients with type III achalasia may be least likely, to report weight loss compared to patients with type I achalasia. Although achalasia cannot be permanently cured, palliation of symptoms is possible in over 90% of patients with the treatment modalities currently available (pneumatic dilation, Heller myotomy, or peroral endoscopic myotomy). This article reviews the clinical presentation, diagnosis, and management options in patients with achalasia, as well as potential insights into histopathologic differences and nutritional implications of the subtypes of achalasia.

Keywords: Achalasia; histopathology; nutrition; weight loss.

Figure 1.

High-resolution manometry showing the 3 subtypes of achalasia. Type I is characterized by a quiescent esophageal body, type II has isobaric panesophageal pressurization, and type III is characterized by simultaneous contractions.

Figure 2.

Loss of inhibitory neurons secreting VIP and NO leads to unopposed excitatory activity and failure of LES relaxation.

Figure 3.

A proposed model for the development of achalasia. Some people with genetic predisposition (HLA class II susceptibility, gene mutations, or certain SNPs) have a viral trigger (herpes simplex virus 1, varicella zoster, or measles) that leads to aggressive inflammatory response. Interactions between T-cell–mediated inflammatory infiltrate, extracellular matrix turnover proteins, and development of humoral response (myenteric antibodies) lead to apoptosis of ganglionic neurons. These events subsequently lead to myenteric plexitis and fibrosis, resulting in impaired relaxation of the LES and absence of esophageal peristalsis.

Figure 4.

Endoscopic images in a patient with achalasia showing (A) a puckered gastroesophageal junction and (B) retained saliva in the proximal esophagus.

Figure 5.

A barium esophagram of a patient with achalasia showing a classic “bird’s beak” due to incomplete relaxation of the lower esophageal sphincter.

Figure 6.

A proposed treatment algorithm for patients with achalasia. POEM, PD, or HM can be considered in all patients with achalasia who have low surgical risk, but POEM and HM might be preferable in patients younger than 40 years who have type III achalasia.