This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Benign Gastric Disease, Subject name: Surgery
[{'content': 'Metabolic abnormality seen in congenital hypertrophic pyloric stenosis is \nSelect and explain. \nA. Hypochloremic hypokalemic metabolic alkalosis, B. Hyperchlonemic hypokalemic metabolic alkalosis, C. Hypochloremic hypokalemic metabolic acidosis, D. Hyperchloremic hypokalemic metabolic acidosis', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e. Hypochloremic hypokalemic metabolic alkalosis * Repeated vomiting leads to hypochloremic, hypokalemic metabolic alkalosis. The urine is alkaline initially but eventually it becomes acidic {paradoxical aciduria)Cause of paradoxical aciduria - Initially the kidney compensate for metabolic alkalosis by reabsorbing hydrogen and chloride ions in exchange for sodium, potassium and bicarbonate. But gradually as the body stores of sodium and especially potassium become depleted, kidney starts retaining these ions in exchange of hydrogen ions, thus the urine becomes acidic and metabolic alkaline state is further aggravated", 'role': 'assistant'}]