This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Renal physiology, Subject name: Physiology
A normal anion gap metabolic acidosis occurs in patients with _______- 
Select and explain. 
A. image_question, B. image_question, C. image_question, D. image_question
A: image_question
Answer: A: image_question 
Explanation: Diarrhoea is a cause of normal anion gap metabolic acidosis produced as a result of increased HCO3+ loss in feces. This is because a decrease in HCO3- is replaced by an increase in the concentration of Cl-. This is a measurable anion and hence the anion gap is normal. Anion Gap in Metabolic Acidosis Normal Anion Gap Increased Anion Gap Renal tubular acidosis Diarrhoea External pancreatic drainage Uterosigmoidostomy Ingestion of ammonium chloride Ketoacidosis Lactic acidosis Chronic renal failure Salicylate intoxication Methanol/Formaldehyde intoxication Ethylene glycol intoxication Ref: Costanzo&;s Physiology 6th edition Pgno: 325