WBR231
| Author | [[PageAuthor::Rim Halaby, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pathology |
| Sub Category | SubCategory::Renal |
| Prompt | [[Prompt::A 68 year old Caucasian male patient presents to his physician for his annual check-up. The patient’s past medical history is significant for hypertension controlled on lisinopril and advanced diabetes mellitus type II poorly controlled on daily insulin injections. Routine work-up reveals elevated serum creatinine. A renal biopsy under light microscopy similar to the patient’s biopsy is shown in the image below. The following findings could be best explained by which of the following pathologic processes?
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| Answer A | AnswerA::Amorphous pink deposits of amyloid in renal cortex |
| Answer A Explanation | [[AnswerAExp::Amyloidosis is characterized by amyloid deposition that is positive for Congo red stain.]] |
| Answer B | AnswerB::Immune response mediated by CD4 and CD8 lymphocytes |
| Answer B Explanation | [[AnswerBExp::Immune response mediated by CD4 and CD8 lymphocytes describes the mechanism of renal rejection following transplantation.]] |
| Answer C | AnswerC::Cystic distribution throughout the renal parenchyma |
| Answer C Explanation | [[AnswerCExp::Polycystic kidney disease is characterized by cystic distribution throughout the renal parenchyma.]] |
| Answer D | AnswerD::Immune complex deposition activating the complement pathway |
| Answer D Explanation | [[AnswerDExp::The pathogenesis of several primary glomerulonephritides, including post-infectious glomerulonephritis and membranoproliferative glomerulonephritis, is characterized by immune complex deposition that activates the complement pathway.]] |
| Answer E | AnswerE::Non-enzymatic glycosylation of proteins |
| Answer E Explanation | AnswerEExp::Diabetic nephropathy is a common microvascular complication in advanced diabetes mellitus. Renal biopsy under light microscopy would reveal characteristic eosinophilic nodules in the glomerular tuft called “Kimmelsteil-Wilson” lesion. |
| Right Answer | RightAnswer::E |
| Explanation | [[Explanation::Diabetic nephropathy is a common microvascular complication in advanced diabetes mellitus. Renal biopsy under light microscopy would reveal characteristic eosinophilic nodules in the glomerular tuft called “Kimmelsteil-Wilson” lesion. Chronic hyperglycemia leads to accumulation of advanced glycosylation end products (AGEs) that trap extravasated immunoglobulins, albumin, LDL, and other proteins via cross-linking to the extra vascular matrix.
Reference: Kalia K, Sharma S, Mistry K. Non-enzymatic glycosylation of immunoglobulins in diabetic nephropathy. Clin Chim Acta. 2004;347(1-2):169-76. |
| Approved | Approved::No |
| Keyword | |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |
