WBR0647

Author	[[PageAuthor::Serge Korjian M.D. (Reviewed by Serge Korjian)]]
Exam Type	USMLE Step 1
Main Category	Pathology, Pathophysiology
Sub Category	Renal
Prompt	[[Prompt::A 22-year-old man presents emergency department in panic after he noticed bright red blood in his urine. Upon questioning, the patient reports he had a similar episode two months ago that resolved spontaneously and did not recur until now. The patient explains that the first episode occurred while he was on sick leave for a viral bronchitis. Physical exam is unremarkable. Urinalysis shows >100 RBCs/HPF, with 1+ proteins noted on dipstick. Which of the following glomerular structures is the most likely to be involved in this patient? ]]
Answer A	A
Answer A Explanation	This refers to the glomerular capillary or endothelial cell. Endothelial involvement is not seen in IgA Nephropathy. It may be seen in lupus nephritis or membranoproliferative glomerulonephritis.
Answer B	B
Answer B Explanation	Mesangial involvement is characteristic of IgA nephropathy.
Answer C	C
Answer C Explanation	This refers to the podocyte. It is affected focal segmental glomerulosclerosis, not in IgA nephropathy (at least in early stages)
Answer D	D
Answer D Explanation	This refers to the glomerular basement membrane which is usually spared in IgA nephropathy. It is involved in the pathogenesis of Alport syndrome and membranoproliferative glomerulonephritis among others.
Answer E	E
Answer E Explanation	This refers to a podocyte foot process which is usually effaced in minimal change disease and is the cause of the proteinuria. Foot processes are not affected in IgA nephropathy.
Right Answer	B
Explanation	[[Explanation:: IgA nephropathy (Berger’s disease) is considered the most common primary chronic glomerulonephritis. The clinical syndrome of IgA nephropathy is often unpredictable, although classically it is recognized as a nephritic syndrome with a presentation of recurrent painless gross hematuria following a respiratory or gastrointestinal tract infection in a young male patient. IgA nephropathy is characterized by the presence of IgA1 deposits along the glomerular mesangium, in addition to complement C3, and properidin. Although not frequently performed, the definitive diagnosis to confirm the clinical suspicion of IgA nephropathy is kidney biopsy. Educational Objective: IgA nephropathy is the leading cause of nephritic syndrome usually presenting with painless hematuria. IgA1 deposits are usually found in the glomerular masangium. References: Donadio JV, Grande JP. IgA nephropathy. N Engl J Med. 2002;347(10):738-48.]]
Approved	Yes
Keyword	IgA Nephropathy, Hematuria, Mesangial pattern, Mesangium, Glomerulonephritis, Nephritic syndrome
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