All are manometric features of achalasia except (not related -medicine)
**Core Concept**
Achalasia is a disorder of the esophagus characterized by the failure of the lower esophageal sphincter (LES) to relax, leading to difficulty in swallowing and regurgitation of food. Manometric features are crucial in diagnosing and understanding the pathophysiology of achalasia.
**Why the Correct Answer is Right**
The manometric features of achalasia include:
- **Prolonged contraction duration**: The contraction wave of the esophagus is prolonged, leading to impaired peristalsis.
- **Increased LES pressure**: The LES fails to relax, resulting in elevated pressures.
- **Absence of peristalsis**: Normal peristaltic waves are absent, indicating esophageal dysmotility.
**Why Each Wrong Option is Incorrect**
**Option A:** This option might be a feature of diffuse esophageal spasm, a different condition characterized by abnormal, uncoordinated contractions of the esophagus.
**Option B:** This could be a feature of esophageal stricture, where the narrowing of the esophagus leads to impaired passage of food.
**Option C:** This might be a feature of gastroesophageal reflux disease (GERD), where the LES relaxes improperly, allowing gastric contents to reflux into the esophagus.
**Clinical Pearl / High-Yield Fact**
Achalasia is often associated with a "bird's beak" appearance on barium swallow studies, where the distal esophagus tapers to a narrow point.
**Correct Answer: D.**