WBR0468
| Author | [[PageAuthor::Rim Halaby, M.D. [1] (Reviewed by Alison Leibowitz)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pathology, MainCategory::Pharmacology |
| Sub Category | SubCategory::Gastrointestinal |
| Prompt | [[Prompt::A 3-year-old male is brought by his mother to the physician's office because she is concerned that he cannot drink milk. He is diagnosed with lactase deficiency. Which cause of diarrhea is most likely characterized by the same diarrhea type associated with lactase deficiency?]] |
| Answer A | AnswerA::Use of lactulose |
| Answer A Explanation | AnswerAExp::Use of lactulose causes osmotic diarrhea. |
| Answer B | AnswerB::Carcinoid tumor |
| Answer B Explanation | AnswerBExp::Carcinoid tumors frequently manifest with secretory diarrhea. |
| Answer C | AnswerC::Rectal villous adenoma |
| Answer C Explanation | AnswerCExp::Rectal villous adenoma frequently manifest with secretory diarrhea. |
| Answer D | AnswerD::Use of selective serotonin reuptake inhibitors (SSRI) |
| Answer D Explanation | AnswerDExp::SSRI use frequently manifest with secretory diarrhea. |
| Answer E | AnswerE::Laxative abuse |
| Answer E Explanation | AnswerEExp::Laxative abuse frequently manifest with secretory diarrhea. |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::Lactulose, a synthetic disaccaride that does not occur naturally, is unable to be digested by human enterocytes. Lactulose-induced diarrhea manifests with a a similar mechanism to that of lactase deficiency induced diarrhea. Since lactulose is not absorbed by the small intestine, the osmolar compounds drive water into the intestinal lumen and cause osmotic diarrhea. Educational Objective: Lactulose is a synthetic disaccharide that is not digested by human enterocytes. Ingestion of lactulose results in osmotic diarrhea, the same type that manifests in lactase deficiency. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::lactulose, WBRKeyword::secretory, WBRKeyword::osmotic diarrhea, WBRKeyword::laxative, WBRKeyword::SSRI, WBRKeyword::rectal, WBRKeyword::rectal villous adenoma, WBRKeyword::lactase deficiency, WBRKeyword::digestive system, WBRKeyword::excretory system, WBRKeyword::membrane transport, WBRKeyword::enzymes |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |