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: Unknown
The following are causes of secretory diarrhea except 
Select and explain. 
A. Vibrio cholera, B. Inflammatory bowel disease, C. Lactose intolerance, D. Gastrinoma
C: Lactose intolerance
Answer: C: Lactose intolerance 
Explanation: Causes of chronic diarrhea: 
1.Osmotic diarrhea—clues—stool volume decreases with fasting, increased stool osmotic gap;
(i) Medications—antacids, lactulose, sorbitol,
(ii) disaccharidase deficiency—lactose intolerance,
(iii) factitious diarrhea—magnesium (antacids, laxatives).
 
2. Secretory diarrhea—clues—large volume (>1 L/day), little change with fasting, normal stool osmotic gap;
(i) hormonally mediated—vipoma, carcinoid, medullary carcinoma of thyroid (calcitonin), Zollinger—Ellison
syndrome (gastrin),
(ii) factitious diarrhea (laxative abuse), phenolphthalein, cascara, senna,
(iii) villous adenoma,
(iv) bile salt malabsorption (ileal resection, Crohn’s ileitis, postcholecystectomy,
(v) medications.