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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor={{Rim}}
|QuestionAuthor= {{SSK}} (Reviewed by Serge Korjian)
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Pathology, Pathophysiology
|MainCategory=Pathology, Pathophysiology
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|MainCategory=Pathology, Pathophysiology
|MainCategory=Pathology, Pathophysiology
|SubCategory=Renal
|SubCategory=Renal
|MainCategory=Pathology, Pathophysiology
|MainCategory=Pathology, Pathophysiology
|MainCategory=Pathology, Pathophysiology
|MainCategory=Pathology, Pathophysiology
|MainCategory=Pathology, Pathophysiology
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|MainCategory=Pathology, Pathophysiology
|MainCategory=Pathology, Pathophysiology
|SubCategory=Renal
|SubCategory=Renal
|Prompt=A 4 year old boy is brought to the emergency department by his mother for facial edema that started gradually 2 days ago. The mother reports that her son was complaining of fatigue for the past week which she attributed to his lack of sleep. She also explains that he suffered from a sore throat 2 weeks ago which was thought to be viral and for which he did not receive any antibiotics. On physical exam you notice marked facial edema with no obvious erythema or rash. You also note that the child's legs and feet are swollen which the mother confirms is more than their usual plump appearance. You order a urinalysis that shows a few red blood cells with a markedly elevated protein-to-creatinine ratio and an estimated 24 hour urine protein of 3.6 g. Which of the following glomerular structures is the most likely to be involved in this patient?
|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?


[[Image:Glomerulus_question.jpg|700px]]
[[Image:Glomerulus_question.jpg|700px]]
|Explanation=[[Image:Labeled_glomerulus.jpg|700px]]
|Explanation=[[Image:Labeled_glomerulus.jpg|800px]]
 
 
Minimal change disease (MCD), also known as lipoid nephrosis, is the most common primary nephrotic syndrome in childhood accounting for >85% of all cases. It usually presents in young children often after an upper respiratory infection. Clinically, the hallmark of MCD like most nephrotic syndromes is edema and massive proteinuria > 3 g/24h (classically selective to albumin) with minimal to absent hematuria. MCD is a T-cell mediated glomerular disease whose cause is not well understood. On light microscopy, kidney biopsy is usually normal or shows very mild lipid accumulation in tubular cells (hence the name lipoid nephrosis). Definitive diagnosis usually requires electron microscopy of the biopsy specimen that would show retained podocytes but with effacement of the podocyte foot processes. The treatment of choice is corticosteroids with 90% of patients responding within 2 weeks of initiation.
 
 
Learning objectives: Minimal change disease is the most common cause of nephrotic syndrome in childhood. It is caused by podocyte foot process effacement.
 


References:
Grimbert P, Audard V, Remy P, Lang P, Sahali D. Recent approaches to the pathogenesis of minimal-change nephrotic syndrome. Nephrol Dial Transplant. 2003;18(2):245-8.


The primary nephrotic syndrome in children. Identification of patients with minimal change nephrotic syndrome from initial response to prednisone. A report of the International Study of Kidney Disease in Children. J Pediatr. 1981;98(4):561-4.
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.
|AnswerA=A
|AnswerA=A
|AnswerAExp=This refers to the glomerular capillary or endothelial cell. Endothelial involvement is not seen in MCD. It may be seen in lupus nephritis or membranoproliferative glomerulonephritis.
|AnswerAExp=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.
|AnswerB=B
|AnswerB=B
|AnswerBExp=Mesangial involvement is seen in IgA nephropathy usually not in MCD.
|AnswerBExp=Mesangial involvement is characteristic of IgA nephropathy.
|AnswerC=C
|AnswerC=C
|AnswerCExp=This refers to the podocyte. Although the foot processes of the podocyte are effaced, the cell itself is not affected.
|AnswerCExp=This refers to the podocyte. It is affected focal segmental glomerulosclerosis, not in IgA nephropathy (at least in early stages)
|AnswerD=D
|AnswerD=D
|AnswerDExp=This refers to the glomerular basement membrane which is usually spared in MCD. It is involved in the pathogenesis of Alport syndrome and membranoproliferative glomerulonephritis among others.
|AnswerDExp=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.
|AnswerE=E
|AnswerE=E
|AnswerEExp=This refers to the podocyte foot processes which are usually effaced in MCD and are the cause of the proteinuria.
|AnswerEExp=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.
|RightAnswer=E
|EducationalObjectives=IgA nephropathy is the leading cause of nephritic syndrome usually presenting with painless hematuria. IgA1 deposits are usually found in the glomerular masangium.
|WBRKeyword=Minimal change disease, proteinuria, podocyte
|References=Donadio JV, Grande JP. IgA nephropathy. N Engl J Med. 2002;347(10):738-48.
|Approved=No
|RightAnswer=B
|WBRKeyword=IgA Nephropathy, Hematuria, Mesangial pattern, Mesangium, Glomerulonephritis, Nephritic syndrome,
|Approved=Yes
}}
}}

Latest revision as of 01:19, 28 October 2020
Author [[PageAuthor::Serge Korjian M.D. (Reviewed by Serge Korjian)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Pathology, MainCategory::Pathophysiology
Sub Category SubCategory::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 AnswerA::A
Answer A Explanation AnswerAExp::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 AnswerB::B
Answer B Explanation AnswerBExp::Mesangial involvement is characteristic of IgA nephropathy.
Answer C AnswerC::C
Answer C Explanation AnswerCExp::This refers to the podocyte. It is affected focal segmental glomerulosclerosis, not in IgA nephropathy (at least in early stages)
Answer D AnswerD::D
Answer D Explanation AnswerDExp::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 AnswerE::E
Answer E Explanation AnswerEExp::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 RightAnswer::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 Approved::Yes
Keyword WBRKeyword::IgA Nephropathy, WBRKeyword::Hematuria, WBRKeyword::Mesangial pattern, WBRKeyword::Mesangium, WBRKeyword::Glomerulonephritis, WBRKeyword::Nephritic syndrome
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