This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Pathology
Achalasia cardia 
Select and explain. 
A. Absence of nerves, B. Absence of muscles, C. Hyperophy of nerves, D. Hyperophy of muscles
A: Absence of nerves
Answer: A: Absence of nerves 
Explanation: Achalasia of the oesophagus is a neuromuscular dysfunction due to which the cardiac sphincter fails to relax during swallowing and results in progressive dysphagia and dilatation of the oesophagus (mega-oesophagus). etiology. There is loss of intramural neurons in the wall of the oesophagus. Most cases are of primary idiopathic achalasia which may be congenital. Secondary achalasia may occur from some other causes which include: Chagas' disease (an epidemic parasitosis with Trypanosoma cruzi), infiltration into the oesophagus by gastric carcinoma or lymphoma, ceain viral infections, and neurodegenerative diseases. TEXTBOOK OF PATHOLOGY HARSH MOHAN 6TH EDITION PAGE NO:538