Differentiating GERD-related regurgitation from achalasia-related regurgitation.

• A. GERD-related regurgitation is acid reflux; achalasia-related regurgitation is regurgitated undigested food due to impaired clearance.
• B. GERD regurgitation is regurgitated undigested food.
• C. Achalasia regurgitation is acid reflux.
• D. Achalasia regurgitation is always accompanied by vomiting.

Answer: (A)

When differentiating regurgitation, focus on the source and what the regurgitated material looks like. GERD causes regurgitation of gastric contents, i.e., acid reflux, which presents as a sour or bitter taste and is often accompanied by heartburn. Achalasia, by contrast, stems from failure of the lower esophageal sphincter to relax and impaired esophageal clearance, so food remains in the esophagus and is regurgitated as undigested material hours after a meal (sometimes at night). This distinction—acid reflux from GERD versus undigested food from achalasia—best captures the different mechanisms. Vomiting is not a defining feature of achalasia regurgitation, which helps separate it from other conditions where vomiting is more prominent.