A 46-year-old woman presents to the clinic with progressive difficulty swallowing over the past year. She initially had trouble swallowing solid foods but now has difficulty swallowing liquids as well. She frequently regurgitates undigested food several hours after meals and has lost 12 pounds during this period. Past medical history is unremarkable, and she does not take any medications. Vital signs are within normal limits. Physical examination is unremarkable. A barium esophagram demonstrates a dilated esophagus with distal tapering. Esophageal manometry shows incomplete relaxation of the lower esophageal sphincter and absent peristalsis.
Which of the following is the most likely underlying cause of this patient’s condition?
The correct answer is:
A) Degeneration of inhibitory neurons in the myenteric plexus
This patient has achalasia, as demonstrated by progressive dysphagia to both solids and liquids, regurgitation of undigested food, a dilated esophagus with distal tapering on barium esophagram, and characteristic manometry findings. Achalasia results from degeneration of inhibitory neurons in the myenteric plexus, leading to impaired lower esophageal sphincter relaxation and absent esophageal peristalsis. The diagnosis is confirmed with esophageal manometry.
Answer choice B: Eosinophilic infiltration of the esophageal mucosa, is incorrect. This answer is attractive because eosinophilic esophagitis can also present with dysphagia. However, eosinophilic esophagitis typically occurs in younger patients with a history of atopic disease (asthma, eczema, allergic rhinitis) and often presents with food impaction. Endoscopy may reveal esophageal rings or linear furrows rather than the classic manometric findings seen in achalasia.
Answer choice C: Fibrosis of the distal esophagus, is incorrect. Fibrosis can produce esophageal strictures that cause progressive dysphagia. However, strictures typically cause dysphagia to solids before liquids and do not produce absent peristalsis on manometry. This answer would be more appropriate in a patient with chronic reflux and endoscopic evidence of a peptic stricture.
Answer choice D: Hypertrophy of the lower esophageal sphincter muscle, is incorrect. The lower esophageal sphincter fails to relax in achalasia, but the primary defect is neuronal rather than muscular. The pathophysiology involves loss of inhibitory neurons that normally mediate sphincter relaxation. This answer choice does not account for the loss of peristalsis seen in this patient.
Answer choice E: Lower esophageal sphincter relaxation due to vagal hyperactivity, is incorrect. Achalasia is characterized by failure of lower esophageal sphincter relaxation, not excessive relaxation. Increased sphincter relaxation would predispose to gastroesophageal reflux disease rather than achalasia.
Key Learning Point
Achalasia causes dysphagia to both solids and liquids due to degeneration of inhibitory myenteric neurons, resulting in impaired lower esophageal sphincter relaxation and absent peristalsis.
