WBR0283

Author	[[PageAuthor::Ayokunle Olubaniyi, M.B,B.S [1] (Reviewed by Yazan Daaboul, M.D. and Alison Leibowitz [2])]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pathology
Sub Category	SubCategory::Renal
Prompt	[[Prompt::A 5-year-old boy is brought to the emergency department (ED) by his mother. She reports that her boy has generalized swelling with decreased urine output, and she is concerned his condition is serious. She explains that first, there was mild swelling around the eyes 3 days ago, but soon his condition worsened and involved the rest of his body. The boy does not report any obvious exacerbating of alleviating factor. The patient has no past medical history with no family history for chronic diseases. Upon further questioning, the mother recalls that the patient was stung by a bee ten days ago. In the ED, the patient's temperature is 36.7 °C (98 °F), his blood pressure 110/72 mmHg, and his heart rate is 82/min. Physical examination is remarkable for generalized pitting edema and a bee sting mark in the left upper extremity. Urinalysis demonstrates oval fat bodies and profound proteinuria. The physician suspects the patient's condition is caused by a renal disease. Which of the following findings on light microscopy is consistent with this patient's diagnosis?]]
Answer A	AnswerA::Segmental sclerosis and hyalinosis
Answer A Explanation	[[AnswerAExp::Segmental sclerosis and hyalinosis are characteristics of focal segmental glomerulosclerosis (FSGS). FSGS is a common cause of nephrotic syndrome among adults and is associated with HIV and sickle cell disease.]]
Answer B	AnswerB::Diffuse capillary and glomerular basement membrane thickening
Answer B Explanation	AnswerBExp::Diffuse capillary and glomerular basement membrane thickening are findings observed in membranous nephropathy (MN). MN is a slowly progressive kidney disease prevalent among Caucasians between 30 and 50 years of age.
Answer C	AnswerC::Normal glomeruli
Answer C Explanation	[[AnswerCExp::The glomeruli in minimal change disease (MCD) appear normal or near-normal when examined using a light microscope. In contrast, electron microscopy demonstrates flattening and fusion of the podocyte foot processes (podocyte effacement).]]
Answer D	AnswerD::Enlarged, hypercellular glomeruli with proliferation of mesangial and endothelial cells
Answer D Explanation	[[AnswerDExp::Enlarged, hypercellular glomeruli with proliferation of mesangial and endothelial cells using a light microscope are findings suggestive of acute post-streptococcal glomerulonephritis, a common cause of nephritic syndrome among pediatric patients. Electron microscopy in PSGN demonstrates subepithelial immune complexes that have a "lumpy-bumpy" appearance. Patients with PSGN typically present with hematuria, hypertension, and periorbital edema with or without oliguria.]]
Answer E	AnswerE::“Wire looping” of capillaries
Answer E Explanation	[[AnswerEExp::“Wire looping” of capillaries is a feature suggestive of diffuse proliferative glomerulonephrits, which is frequently observed among patients with systemic lupus erythematosus (SLE).]]
Right Answer	RightAnswer::C
Explanation	[[Explanation::The boy in this scenario has nephrotic syndrome, characterized by proteinuria, hypoalbuminemia, and edema. Minimal change disease, also referred to as lipoid nephrosis, is the most common cause of nephrotic syndrome in very young children. It usually starts with facial edema and can be triggered by a bee sting, previous upper respiratory tract infections, drugs, or malignancies. Treatment is very effective with corticosteroids. Educational Objective: Nephrotic syndrome (NS) is characterized by proteinuria, hypoalbuminemia, and edema. Minimal change disease (MCD) is the most common cause of NS in children. MCD is often steroid-responsive, and the majority of patients achieve remission with steroids. References: First Aid 2014 page 536]]
Approved	Approved::Yes
Keyword	WBRKeyword::Nephrotic syndrome, WBRKeyword::Minimal change disease, WBRKeyword::Proteinuria, WBRKeyword::Renal, WBRKeyword::Kidney, WBRKeyword::Lipoid nephrosis
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