WBR0415

Author	[[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Yazan Daaboul, M.D.)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pathology
Sub Category	SubCategory::Renal
Prompt	[[Prompt::A 52-year-old man with an unknown past medical history dies following a motor vehicle collision. On autopsy, his kidneys have the following appearance as shown in the image below. Which of the following clinical findings is mostly associated with this patient's condition? ]]
Answer A	AnswerA::Large hepatic multiacinar regenerative nodules
Answer A Explanation	[[AnswerAExp::Large hepatic multiacinar regenerative nodules are characteristic of hepatic fibrosis. Congenital hepatic fibrosis is common among patients with autosomal recessive polycystic kidney disease (ARPKD), which manifests early in childhood. In contrast, ADPKD manifests during adulthood with progressive renal insufficiency and end-stage-renal disease, and it is associated with the development of extrarenal cysts (e.g. hepatic and pancreatic cysts and cysts in the seminal vesicle), aneurysms (e.g. cerebral berry aneurysm), colonic diverticula, and mitral valve prolapse.]]
Answer B	AnswerB::Granulomatous inflammation and skip lesions in a bowel segment
Answer B Explanation	[[AnswerBExp::Granulomatous inflammation and skip lesions are characteristic of Crohn’s disease. ADPKD is not classically associated with Crohn’s disease.]]
Answer C	AnswerC::Cranial nerve compression by an adjacent structure
Answer C Explanation	[[AnswerCExp::Autosomal (adult) dominant polycystic kidney disease (ADPKD) is an inherited renal disorder characterized by the development of fluid-filled cysts in both kidneys during adulthood. It is associated with the development of berry aneurysms, which may cause mechanical compression of the nearby CN III in the event of development of posterior communicating artery aneurysm.]]
Answer D	AnswerD::Granulomatous inflammation of a great vessel
Answer D Explanation	[[AnswerDExp::Granulomatous inflammation of the aorta is a characteristic feature of Takayasu vasculitis (pulseless disease).]]
Answer E	AnswerE::Obliteration of the biliary tree
Answer E Explanation	[[AnswerEExp::Obliteration of the biliary tree is characteristic of sclerosing cholangitis. Sclerosing cholangitis is classically associated with ulcerative colitis, not ADPKD.]]
Right Answer	RightAnswer::C
Explanation	[[Explanation::Autosomal (adult) dominant polycystic kidney disease (ADPKD) is an inherited renal disease usually caused by a mutation of either the PKD1 gene in chromosome 16 (common) or the PKD2 gene in chromosome 4 (less common). It is characterized by fluid-filled cystic enlargement in both kidneys during adulthood that progressively leads to renal failure. Patients usually present with flank pain, hematuria, and hypertension. ADPKD is associated with berry aneurysms and development of multiple hepatic and pancreatic cysts, colonic diverticula, and mitral valve prolapse. Berry aneurysms are caused by weakness of the cerebral artery walls, which results in dilation of the affected artery. Aneurysm formation in the posterior communicating artery may lead to compression of CN III (oculomotor cranial nerve). CN III contains an inner central motor component and an outer peripheral parasympathetic component. Accordingly, different diseases may affect CN III differently. Mechanical compression of CN III affects the outer parasympathetic component and leads to “blown pupils” with absent papillary light reflex. On the other hand, vascular diseases, such as long-standing diabetes mellitus, cause ischemic injury to the inner motor component, and patients present with a “down and out” gaze when the inner motor component is affected. Educational Objective: Autosomal (adult) dominant polycystic kidney disease (ADPKD) is an inherited renal disorder characterized by the development fluid-filled cysts in both kidneys during adulthood. ADPKD is associated with berry aneurysms that may affect the posterior communicating artery and result in the mechanical compression of CN III. References: First Aid 2015 page 87, 465, 551 Image Attribution: CDC/Dr. Edwin P. Ewing, Jr. "861 Description: Gross pathology of polycystic kidneys" public domain distribution by the Centers for Disease Control and Prevention - United States Department of Health and Human Services.]]
Approved	Approved::Yes
Keyword	WBRKeyword::Autosomal dominant, WBRKeyword::ADPKD, WBRKeyword::Renal failure, WBRKeyword::Motor vehicle collision, WBRKeyword::Genetics, WBRKeyword::Autosomal dominant polycystic kidney disease, WBRKeyword::Pattern of inheritance, WBRKeyword::Berry aneurysms, WBRKeyword::CN III, WBRKeyword::Motor vehicle collision, WBRKeyword::Adult dominant polycystic kidney disease
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