05.14 - Nephrotic Syndrome 2 (Nichols, Showkat) - PP + Handout Flashcards
suPAR
Binds Beta3-integrin –> FSGS
Reduce __ is associated with secondary FSGS
Reduced nephron mass
Chronic, slowly progressive disease wih GBM thickening, Subepithelial immune complex deposits, and effacement of foot processes
Membranous Nephropathy
IF of Post-Strep GN
Diffuse granular deposts of IgG and C3
Prognosis of Post-Strep GN
Generally good in children; 40% of adults develop chronic azotemia
ApoL1 mutation makes you susceptible to
FSGS
AI w/ immune complexes formed in situ from binding of filtered auto-ab to podocyte m-type PLA2R
Probably pathogenic mechanism causing most cases of Primary Membranous Nephropathy
IF in MCD and FSGS are usually both
negative
Role of suPAR, beta3-integrin, and podocytes in Focal Segmental Glomerulosclerosis
suPAR binds to and activates beta3-integrin, a major podocyte anchoring protein
EM of Focal Segmental Glomerulosclerosis
Effacement of foot processes
If poor response to steroids in MCD, think of
Unsampled focal segmental glomerulosclerosis
Why is effacement of foot process likely mediated by MAC
Intermediary chemotactic fragments, C3a and C5a, are washed away into urinary space
Demographic of Post-Strep GN
School age children, male preponderance
LM of Membranous Nephropathy
Thickening of GBM
Most common demographic of Focal Segmental Glomerulosclerosis
Adult black males
Why no inflammation in Membranous Nephropathy
Complement not activated b/c at a site that is not in contact with circulating inflammatory cells
Most common cause of Nephortic Syndrome in Caucasian Adults
Membranous Nephropathy
Thickened GBM w/out increased cellularity
Membranous Nephropathy
Most common cause of Nephrotic Syndrome in Black Adults
64% Focal Segmental Glomerulosclerosis
IF of FSGS
Normal
Membranous Nephropathy vs Post-Infectious GN: Which is nephritic and which nephrotic
Membranous Nephropathy is nephrotic
Diffuse endocapillary proliferation and infiltration by numerous neutrophils
Post-Strep GN
IF of Membranous Nephropathy
Granular subepithelial deposits of IgG and Complement
Complement changes in Post-Strep GN
Low C3, but normal C4 - Demonstrates alternative pathway activation
Suggested pathogenesis of Focal Segmental Glomerulosclerosis
suPAR binds to and activates beta3-integrin, a major podocyte anchoring protein
What causes Spike and Dome appearance
Subepithelial deposits with thin tracts of new GBM separating the deposits
Which subtype of Focal Segmental Glomerulosclerosis has a rapid onset of nephrotic syndrome with rapid progression to renal failure
Collapsing Glomerulopathy
What is hyalinosis in FSGS
Accumulation of leaked plasma protiens and lipids
What causes 75% of nephrotic syndrome cases in children
Minimal Change Disease
Soluble Urokinase-type plasminogen activator receptor (suPAR) is elevated in serum of 2/3 of patients with
Focal Segmental Glomerulosclerosis
Tx of FSGS
Corticosteroids (poor response) and Calcineurin inhibitors
LM histology of Focal Segmental Glomerulosclerosis
Scarring, Adhesions to bowman’s capsule, Occluded cap lumens, Hyalinosis
The Collapsing Glomerulopathy subtype of FSGS is often associated with
HIV infection or drug toxicity
suPAR binds to and activates
Beta3-integrin, a major podocyte-anchoring protein
Prognosis of Minimal Change Disease
Resolves with steroid tx in >90% of kids; Response slow in adults; Recurrence is common
Minimal change disease causes about__ of nephrotic cases in children
75%
What mutation in AA’s confers 10.5-fold higher incidence of Focal Segmental Glomerulosclerosis
ApoL1
5 features accompanying Nephrotic Syndrome that indicate FSGS over MCD
Older Age, Hematuria, HTN, Non-selective Proteinuria, Poor response to steroids
Probably pathogenic mechanism causing most cases of Primary Membranous Nephropathy
AI w/ immune complexes formed in situ from binding of filtered auto-ab to podocyte m-type PLA2R
Ages of minimal change disease
Very young or very old
Presentation of Membranous Nephropathy
Most with nephrotic syndrome, rest with asymptomatic proteinuria
Most common subtype of Focal Segmental Glomerulosclerosis
Not Otherwise Specified
Demographic of Membranous Nephropathy
Caucasian Male Adults
EM of Membranous Nephropathy
Effacement of FP’s and Spike and Dome: Subepithelial deposits with tracks of BM separating them
Top two findings in FSGS
Nephrotic Range Proteinuria, Hematuria
LM of Post-Strep GN
Diffuse proliferative GN, prominent endocapillary proliferation and numerous neutrophils
NEP is the target antigen in
Congenital Membranous nephropathy
m-type PLA2
Immune complexes –> Most primary Membranous Nephropathy
LM, IF, and EM of Minimal Change Disease
LM and IF are negative, but EM shows foot process effacement
Post-Strep GN typically presents with
Nephritic Syndrome
Tea or Cola Colored Urine
Post-Infectious GN
Why is it important to differentiate FSGS from MCD
Prognosis is much worse in FSGS
PLA2R is the target antigen in
Primary (idiopathic) Membranous Nephopathy
EM of Post-Strep GN
Subepithelial electron-dense deposits = Humps
Insidious onset of Nephrotic Syndrome in child with good response to steroid tx
Minimal Change Disease
Cornerstone of tx in Minimal Change Disease
Oral Glucocorticoids
What causes podocyte injury in Membranous Nephropathy
Formation of MAC due to auto-Ab binding (to m-type PLA2R)
Time fram of Post-Strep GN after infection
1-6 weeks