This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'Hypochloremic alkalosis is seen in: March 2009 \nSelect and explain. \nA. Achalasia cardia, B. Congenital hyperophic pyloric stenosis, C. Ureterosigmoidostomy, D. Diarrhea', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. B: Congenital hyperophic pyloric stenosis Blood tests in congenital pyloric stenosis reveals hypokalemic, hypochloremic metabolic alkalosis due to loss of gastric acid (which contain hydrochloric acid and potassium) persistent vomiting; these findings can be seen with severe vomiting from any cause. The potassium is decreased fuher by the body's release of aldosterone, in an attempt to compensate for the hypovolaemia due to the severe vomiting. Chronic hyperchloraemic metabolic acidosis occurs secondary to ureterosigmoidostomy.", 'role': 'assistant'}]