WBR0419
| Author | [[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Yazan Daaboul, M.D. and Alison Leibowitz [1])]] |
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| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Embryology |
| Sub Category | SubCategory::Renal |
| Prompt | [[Prompt::A 19-year-old man presents to the emergency department with complaints of abdominal pain. The physician orders abdominal and pelvic CT scans, but the etiology of the patient's abdominal pain is undetermined by imaging. An incidental finding is documented in the CT scan image shown below. Which of the following arteries is involved in the anatomic location of this patient’s incidental finding?
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| Answer A | AnswerA::Umbilical artery |
| Answer A Explanation | [[AnswerAExp::Umbilical artery is not involved in the anatomic location of horseshoe kidney.]] |
| Answer B | AnswerB::Superior mesenteric artery (SMA) |
| Answer B Explanation | [[AnswerBExp::The superior mesenteric artery (SMA) is not involved in the anatomic location of horseshoe kidney.]] |
| Answer C | AnswerC::Inferior mesenteric artery (IMA) |
| Answer C Explanation | [[AnswerCExp::The inferior mesenteric artery (IMA) blocks the ascent of the horseshoe kidney and the latter remains low in the abdomen.]] |
| Answer D | AnswerD::Descending aorta |
| Answer D Explanation | [[AnswerDExp::Descending aorta is not involved in the anatomic location of horseshoe kidney.]] |
| Answer E | AnswerE::Renal artery |
| Answer E Explanation | [[AnswerEExp::Renal artery is not involved in the anatomic location of horseshoe kidney.]] |
| Right Answer | RightAnswer::C |
| Explanation | [[Explanation::Horseshoe kidney (HSK) is a congenital disorder caused by renal fusion at the lower poles (connected by fibrous isthmus). It is the result of 3 anatomic anomalies of the urinary tract: ectopia, malrotation, and vascular alterations. As the fused kidney ascends during embryological development from the level of the lower lumbar vertebrae, the inferior mesenteric artery (IMA) hinders its ascent, and the kidney remains low in the abdomen. Accordingly, the horseshoe kidney malrotates and the renal pelvises are located anteriorly at the level of the lower lumbar vertebae. Horseshoe kidneys are frequently incidental findings during ultrasound, abdominal CT scan, or IV pyelography because it is an asymptomatic condition and kidney function is generally not impaired. HSK is associated with the development of renal malignancies, such as Wilms' tumor and HSK carcinoid.
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| Approved | Approved::Yes |
| Keyword | WBRKeyword::Horseshoe kidney, WBRKeyword::Kidney, WBRKeyword::Arteries, WBRKeyword::IMA, WBRKeyword::Incidental finding, WBRKeyword::Inferior mesenteric artery, WBRKeyword::Congenital disorder, WBRKeyword::Inherited disorder, WBRKeyword::HSK, WBRKeyword::Malrotation, WBRKeyword::Ectopia, WBRKeyword::Vascular alterations, WBRKeyword::Vascular changes, WBRKeyword::Embryological development, WBRKeyword::Lumbar vertebrae |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
