Achalasia 2

Question

Vignette: A 45-year-old woman presents to the clinic with a 6-month history of difficulty swallowing both solids and liquids. She reports having lost weight unintentionally over the past few months. She denies any other symptoms, including heartburn, chest pain, or regurgitation. Her past medical history is unremarkable and she does not smoke or drink alcohol. On physical examination, her vitals are within normal limits. A barium swallow is performed and shows a dilated esophagus with a "bird's beak" appearance at the distal end. The most likely diagnosis in this patient is caused by which of the following?

Choices

A. Decreased lower esophageal sphincter pressure

B. Disruption of the myenteric plexus

C. Increased lower esophageal sphincter pressure

D. Increased parietal cell mass

E. Malfunction of G cells in the stomach

Answer

B. Disruption of the myenteric plexus

Explanation

This patient's presentation of dysphagia to both solids and liquids, weight loss, and a "bird's beak" appearance of the esophagus on barium swallow is suggestive of achalasia. Achalasia is a primary esophageal motility disorder characterized by the loss of peristalsis in the distal two-thirds of the esophagus (which is normally controlled by the myenteric plexus) and failure of relaxation of the lower esophageal sphincter. This results in a functional obstruction at the gastroesophageal junction, leading to the classic radiographic "bird's beak" appearance. The exact cause of achalasia is unknown, but it is thought to result from a selective loss of inhibitory neurons in the myenteric (Auerbach) plexus, leading to unopposed action of excitatory neurons. The resulting imbalance in the excitatory and inhibitory input to the smooth muscle cells of the esophagus leads to aperistalsis and increased lower esophageal sphincter tone.