Group1 Flashcards
principle causes of ESRD (2)
44% diabetes, 27% HTN
glomerular barrier parts (3)
fenestrated capillary endothelium, basement membrane, podocyte foot processes with slit diaphragms made up of nephrin
normal urine proteins (amount, % of two major) and what level of proteinuria is nephrotic?
Normal urine has < 150 mg/day proteins: 45% Tamm Horsfall (secreted by TAL epithelium), 35% albumin (escapes reabsorption in PCT); if urine has more than 3.5 g/day it must be glomerular in origin
selective proteinuria: urine findings, mechanism, pathophys
pathophys: minimal change disease; mechanism: foot process effacement (loss of charge barrier?); urine: albumin, transferrin, no IgG (too big)
non-selective proteinuria
pathophys: most glomerulopathy other than min change disease; mechanism: foot process effacement (loss of size barrier?); urine: albumin, transferrin, IgG
proximal tubular dysfn proteinuria: urine findings, mechanism, pathophys
mech: decr reabs of filtered protein; pathophys: tubulo-interstitial dis, Fanconi; urine: <3 g day proteinuria (B2 microglobulin, lysozyme, albumin) along w/ other signs of PCT dysfn (glucose, bicarb, AA, etc.)
overload proteinuria: urine findings, mechanism, pathophys
pathophys: plasma cell dyscrasias (multiple myeloma); mech: incr # small, abnormal filterable serum proteins, these proteins can cause PCT toxicity/cast formation (prevent reabs of albumin); urine: <3 g day (non-glomelular), normal urine dipstick for protein (altho poss incr albumin), lots of IgG light chains (Bence Jones protein)
orthostatic proteinuria: urine findings, pathophys
pathophy: not pathological (seen in healthy teens/young adults); <2 g day proteinuria that appears in first morning urine when pt becomes upright
functional proteinuria
not pathological, seen in pts w/ high fever, CHF, cold exposure, resolves w/ resolution of precipitating event
best method for long term follow-up of proteinuria
spot urine protein:creatinine ratio
spot urine protein:creatinine ratio
best method for long-term follow-up; detects all protein; Upr/Ucr ~ 24 hr protein excretion (nl <.15) b/c Ucr ~ 1000 mg/day; this underestimates Upr in muscular men and overestimates Upr in elderly pts, but still useful for tracking vs time b/c Ucr shouldn’t change
nephrotic syndrome
non-inflammatory glomerulopathy (seen in CKD); syndrome: glomerular proteinuria (>3.5 g/day), hypoproteinemia, edema, hyperlipidemia
diff dx of edema (5)
proteinuria, renal failure, CHF, liver failure, protein malnutrition
complications of nephrotic syndrome (3)
hypercoagulability (due to loss of antithrombin proteins), infection, atherogenesis
histopathologies of nephrotic syndrome (3)
minimal change disease; focal segmental glomerulosclerosis; membranous glomerulopathy
mechs of injury in nephrotic syndrome (3)
minimal change -> unclear (T/B mediated); FSGS -> podocyte injury; MGN -> in-situ immune complex to some antigen on podocytes
minimal change disease: type of what, LM/FM/EM, etiology, demographics, tx (2), prognosis (3)
type of histopath in nephrotic syndrome; normal cx on LM, negative FM, but EM shows foot process effacement; etiology either primary (poss B/T cell mediated) or secondary (NSAIDs, lymphoma); seen mostly in kids; tx w/ corticosteroids for 6 weeks (90-95% remission) -> may give kids steroid trial rather than biopsy if they have nephrotic syndrome w/o HTN and hematuria and w/ normal GFR and C3; 33% never relapse after tx, 33% occasionally relapse, and 33% frequently relapse (>3 in 6 mos)
FSGS: type of what, LM/FM/EM, pathogenesis, FSGS factor, demographics (2)
type of histopath in nephrotic syndrome; LM has focal (some glomeruli) segmental (parts of these glomeruli) scleroris (too much ECM) w/ segmental collapse w/ adhesions to Bowman’s capsule, FM has IgM and C3 in mesangium of collapsed segments, EM has foot process effacement, focal podocyte injury or denudation of GBM, collapse of cap loops w/ accumulation of hyalin; pathogenesis: final common pathway for glom injury, due to podocyte injury w/ loss of podocytes in urine -> segmental sclerosis; may be due to uPAR (circulating factor, explains why transplanted kidneys can get FSGS in FSGS pts); common in elderly (infantile FSGS is monogenetic)
uPAR
circulating FSGS factor (explains why pts w/ FSGS can get FSGS in donated kidneys)
what disease has no findings on LM or FM but has foot process effacement on EM?
minimal change disease
what disease is assoc w/ injury and loss of podocytes?
FSGS
what disease has FM of IgM and C3 in mesangium?
FSGS
what disease has EM of foot process effacement, focal podocyte injury or denudation of GBM, collapse of capillary loops w/ accumulation of hyalin
FSGS
what nephrotic syndrome is common in kids?
minimal change disease
what nephrotic syndrome is common in elderly?
FSGS
when do we try a steroid trial?
kids w/ nephrotic syndrome w/o HTN and hematuria and w/ normal GFR and C3 -> way to avoid biopsy if we believe they may have minimal change disease
membranous glomerulopathy: type of, LM/FM/EM, etiology (7), natural hx (3)
type of histopath in nephrotic syndrome; LM: thickened glomerular cap loops (thickened BM) w/ BM spikes seen on PAS and subepithelial deposits seen in trichrome, FM: IgG and C3 in granular cap loop deposits (secondary MGN has both cap loop and mesangial deposits of more proteins), EM: foot process effacement, subepithelial electron dense deposits w/ variable amounts of BM surrounding them, secondary MGN may have subendothelial and mesangial deposits too; primary MGN: subepithelial immune complexes form in situ against podocyte membrane antigen (assoc w/ HLA types); secondary: infx (hep B/C, malaria), neoplasms (lung, colon, gastric, breast), meds (gold salts, penicillinamine), SLE; natural hx: 20% spontaneous remission, 60% persistent proteinuria w/o GFR decline; 20% progressive w/ GFR decline
etiology of MGN
primary MGN: subepithelial immune complexes form in situ against podocyte membrane antigen (assoc w/ HLA types); secondary: infx (hep B/C, malaria), neoplasms (lung, colon, gastric, breast), meds (gold salts, penicillinamine), SLE
what disease can be caused by hep B/C?
MGN
what disease can be caused by HIV?
FSGS
what disease can be caused by malaria?
MGN
what disease can be caused by gold salts?
MGN
what disease can be caused by penicillamine?
MGN
what disease can be caused by neoplasm?
lung/colon/gastric/breast cancer -> MGN; lymphoma -> minimal change disease
what disease can be caused by NSAIDS?
minimal change disease and interstitial nephritis; NSAIDS also cause GFR decline (no afferent dilation)
what disease has LM of: thickened glomerular cap loops w/ BM spikes seen on PAS and subepithelial deposits seen in trichrome
MGN
what disease of EM of: foot process effacement, subepithelial electron dense deposits w/ variable amounts of BM surrounding them
MGN
what disease has FM of: IgG and C3 in granular cap loop deposits
MGN (can have mesangial and other staining in secondary MGN), post-strep (w/ mesangial deposits too), lupus (w/ mesangial deposits and positive w/ other stains too)
FM in nephrotic syndromes
minimal change disease: no staining; FSGS: IgM/C3 in mesangium; MGN: IgG/C3 in granular cap loop deposits (secondary MGN can have more proteins in granular loop and mesangial deposits)
hematuria/proteinuria differential dx
glomerular disease likely if hematuria and proteinuria (either inflammatory glomerulonephritis aka nephritic syndrome or diabetic nephropathy or heriditary GBM disease); non-glomerular disease likely if hematuria only (if >40 yo, consider cancer, stones, infx; if <40 yo, consider stones, infx, trauma); nephrotic syndrome likely if proteinuria only
nephritic syndrome
inflammatory glomerulonephritis (seen in acute and subacute renal failure); syndrome: microscopic hematuria (RBC casts, dysmorphic RBCs), proteinuria (not as high as nephrotic syndrome), HTN, edema
nephritic syndrome mnemonic
PHARAOH = Proteinuria, Hematuria, Azotemia, RBC casts, Anti-strep titres (if post-strep), Oliguria, Hypertension
nephritic vs nephrotic
nephritic is inflammatory, acute, has hematuria (dysmorphic RBC/RBC casts) and mild proteinuria (3.5 g proteinuria w/o hematuria; nephritic assoc w/ HTN; nephrotic assoc w/ hyperlipidemia and hypoalbuminemia; both have edema (nephrotic due to hypoalbuminemia, nephritic due to Na retention b/c nephritic assoc. w AKI)
Rapidly Progressive Glomerulonephritis
2 nested clinical syndromes: subacute rise in Pcr w/ nephritic syndrome
pathophys of nephritic syndrome (5 events and timeline)
Capillary wall injury -> proliferation w/in 24 hrs (influx of immune cells to glomerular tuft, not prolif of endogenous glom. cells = hypercellularity on LM) -> acellular crescent formation (4 days, made up of fibrinogen) -> cellular crescent formation (7 days, immune cells and fibroblasts gel onto acellular crescent)-> glomerular and interstitial scarring by fibroblasts (30 days -> irreversible nephron loss)
nephritic syndrome diff dx
antibody mediated (anti GBM/Goodpasture’s); immune complex mediated (post-strep, lupus, IgA/HSP); pauci-immune glomerulonephritis (ANCA positive small vessel vasculitis)