TRUE statement about achalasia cardia is:
**Core Concept**
Achalasia cardia is a primary motility disorder of the esophagus characterized by the failure of the lower esophageal sphincter (LES) to relax, leading to impaired esophageal emptying and difficulty swallowing. This condition is often associated with degeneration of the myenteric plexus, which is responsible for coordinating esophageal peristalsis.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of achalasia cardia. The failure of the LES to relax is a critical aspect of this condition, leading to increased intraluminal pressure and impaired esophageal emptying. This is often due to the degeneration of the myenteric plexus, a complex network of neurons that regulates esophageal motility.
**Why Each Wrong Option is Incorrect**
**Option A:** This option may be related to a different esophageal condition, such as esophageal stricture or carcinoma, which can also cause difficulty swallowing. However, it is not a characteristic of achalasia cardia.
**Option B:** This option is incorrect because it is actually a characteristic of diffuse esophageal spasm, a different esophageal motility disorder. Diffuse esophageal spasm is characterized by abnormal, simultaneous contractions of the esophagus.
**Option C:** This option is incorrect because it is actually a characteristic of esophageal carcinoma, which can cause difficulty swallowing and weight loss. However, esophageal carcinoma is a different condition from achalasia cardia.
**Clinical Pearl / High-Yield Fact**
Achalasia cardia is often associated with a "bird's beak" appearance on barium swallow studies, due to the dilated esophagus and narrowed lower esophageal sphincter. This is a classic radiographic finding that can help diagnose this condition.
**Correct Answer:** C.