Fung > renal path Flashcards
what are the 3 metabolic fxns of the kidney?
- excrete ions (water, Na, Ca, P)
- maintain acid-base balance
- excrete toxic metabolic waste pdts
what are the 2 endocrine fxns of the kidney?
- secrete EPO & PGs
2. regulate vitamin D metabolism
how does the kidney regulate BP?
secretes renin
what are the 3 main renal fxns?
- metabolism
- endocrine
- regulate BP
if you have a histo slide w/ glomeruli, what part of the kidney are you in?
cortex
what is the endothelium of the renal cortex?
fenestrated endothelial cells
where is the endothelium of the renal cortex located?
adjacent to the lamina rara interna of the GBM
what is another name for visceral epithelium?
podocytes
where are the podocytes?
adjacent to the lamina rara externa of the GBM (externa > epi)
what is unique about podocytes?
foot processes separated by filtration slits
how many layers does the GBM have?
3
what are the layers of the GBM?
lamina rara interna
lamina densa
lamina rara externa
the GBM is composed of what 6 things?
- type IV collagen
- laminin
- heparan sulfate
- fibronectin
- entactin
- glycoproteins
what does the mesangium do?
supports the glomerular tuft
where is the mesangium?
btwn capillaries in the cortex
what does the mesangium contain?
matrix similar to the basement membrane
what 4 things are special about mesangial cells?
- contractile
- phagocytic
- secrete mediators
- lay down matrix
what are mesangial cells similar to?
vascular smooth muscle cells & pericytes
how can you tell the DCT apart from the PCT?
the DCT has a wider lumen
the PCT has fatter cells and is cloudier in the lumen
what structures are in the renal medulla (think histo)?
collecting ducts & tubules
NO GLOMERULI
T/F: renal disease is always caused by primary reasons
FALSE
tons of diverse causes
what are the 4 basic patterns of rxns in response to glomerular injury?
- hypercellularity
- BM thickening
- hyalinosis
- sclerosis
define diffuse
involving ALL glomeruli
define focal
involving SOME glomeruli
define global
involving a WHOLE glomerulus
define segmental
involving PART of a glomerulus
what is most glomerular injury d/t (generally)?
immunologic causes
what are the 3 ways immunologic causes can injury a glomerulus?
- ab rxn in situ w/i glomerulus
- circulating ab deposits w/i glomerulus
- cytotoxic ab directed against the glomerulus
when cytotoxic ab are directed against the glomerulus, what pathway is activated?
complement
when circulating ab gets deposited in the glomerulus, what types of ag are involved (generally)?
endogenous
AND
exogenous
when ab reacts in situ w/i the glomerulus, what types of ag are involved?
intrinsic glomerular ag
AND
ag planted w/i the glomerulus
what is the biggest difference btwn CIRCULATING ab & IN SITU ab deposits?
the circulating deposits are actually immune COMPLEXES w/ ab & ag
(in situ means that the ag is already IN the glomerulus, so the ab just comes in and reacts w/ that)
what clinical presentations can glomerular injury lead to?
nephrotic syndrome nephritic syndrome rapidly progressive glomerulonephritis chronic renal failure asymptomatic hematuria
define azotemia
BUN or Cr elevation, either prerenal, intrinsic, or postrenal
what is acute renal failure?
rapid decline in GFR
how long is “rapid” in acute renal failure?
hours to days
what are the 3 characteristics of acute renal failure?
- azotemia
- fluid & electrolyte imbalance
- oliguria or anuria
what types of fluid & electrolyte imbalances can be found w/ acute renal failure?
hyponatremia hyperkalemia hyperphosphatemia hypocalcemia metabolic acidosis
what are the 4 causes of acute renal failure?
- glomerular injury
- interstitial injury
- vascular injury
- tubular injury
what are the 4 sx of acute renal failure?
- decreased/absent urine output
- lethargy
- fatigue
- nausea
what 5 categories can you use to distinguish btwn prerenal and renal acute renal failure?
- FENa+
- BUN/Cr
- Urine Na+
- Urine osmolality
- Specific gravity
how does FENa+ differ btwn prerenal and renal acute renal failure?
prerenal: 1%
renal: >1%
how does BUN/Cr differ btwn prerenal and renal acute renal failure?
prerenal: >20:1
renal: <20:1
how does Urine Na+ differ btwn prerenal and renal acute renal failure?
prerenal: 20mEq/L
how does urine osmolality differ btwn prerenal and renal acute renal failure?
prerenal: >500 mOsm/kg
renal: <400 mOsm/kg
how does specific gravity differ btwn prerenal and renal acute renal failure?
prerenal: >1.020
renal: <1.020
what is chronic renal failure?
diminished GFR for at least 3 months
what constitutes “diminshed” GFR in chronic renal failure?
<60 mL/minute/1.73m^2
what are the 3 characteristics of chronic renal failure?
- azotemia
- fluid & electrolyte imbalance
- uremia
(1 & 2 are the same as acute)
what is uremia?
a syndrome assoc w/ fluid, electrolyte, & hormonal imbalances + metabolic abnormalities
what are the sx of uremia?
N/V fatigue anorexia weight loss muscle cramps pruritis mental status change visual disturbances inc thirst
what are the 3 main causes of chronic renal failure?
- diabetes
- HTN
- renal parenchymal disease
how bad does GFR get w/ chronic renal failure?
<20-25% of normal
what is the difference btwn chronic renal failure & end stage renal disease in terms of GFR?
chronic renal failure is <5% of normal
what are the 4 sx of nephritic syndrome?
- hematuria (RBC casts)
- azotemia
- oliguria
- slight proteinuria
what characterizes nephritic syndrome?
INFLAMMATION of glomeruli
the i in nephritic means inflammation
what are the sx of acute proliferative glomerulonephritis?
- URI or skin infection 1-6 wks prior
- gross hematuria
- oliguria
- RBC casts
- peripheral edema
- HTN
- azotemia
- mild proteinuria
(2, 3, 4, & 8 = nephritic syndrome)
what causes acute proliferative glomerulonephritis?
beta-hemolytic group A strep
Lancefield M types 1, 2, 4, 12, 47, 49, 57
what is another name for acute proliferative glomerulonephritis?
poststreptococcal glomerulonephritis (PSGN) (pathoma)
what is the pathogenesis of acute proliferative glomerulonephritis?
circulating immune complexes are deposited in the glomerulus (subepithelial HUMPS)
what findings will you see for acute proliferative glomerulonephritis on IF & EM?
IF: granular d/t immune complexes
EM: subepithelial humps d/t immune complexes
what does acute proliferative glomerulonephritis look like on H&E?
hypercellular
inflamed glomeruli
name the nephritides according to pathoma
- post-strep glomerulonephritis (acute proliferative)
- rapidly progressive glomerulonephritis
- IgA nephropathy (Berger)
- Alport syndrome
what is the difference btwn the clinical course of acute proliferative glomerulonephritis in adults vs kids?
KIDS: 95% recover totally
ADULTS: only 60% recover
what is the therapy for acute proliferative glomerulonephritis in kids?
maintain Na & water balance (i.e. supportive therapy bc most kids recover)
what can acute proliferative glomerulonephritis progress to?
rapidly progressive glomerulonephritis
what characterizes rapidly progressive glomerulonephritis?
- rapid & progressive loss of renal fxn
- oliguria
- nephritic sx
what can you see on H&E & IF w/ rapidly progressive glomerulonephritis?
crescents in Bowman’s space made of FIBRIN & MACS
what are the 3 types of rapidly progressive glomerulonephritis?
- Type I > anti-GBM ab
- Type II > immune complex
- Type III > pauci-immune
what characterizes type I rapidly progressive glomerulonephritis?
LINEAR deposits of IgG/C3
what is the treatment for type I rapidly progressive glomerulonephritis?
plasmapharesis
immunosuppression
what are the causes of type II rapidly progressive glomerulonephritis?
- complication of post-infectious glomerulonephritis
- lupus nephritis complication
- IgA nephropathy
- idiopathic
what is the treatment for type II rapidly progressive glomerulonephritis?
treat the UNDERLYING DISEASE!
DO NOT DO PLASMAPHARESIS
what is the diff btwn type I & type II rapidly progressive glomerulonephritis on IF?
type I is LINEAR
type II is GRANULAR
what kind of ab do you have in Type III rapidly progressive glomerulonephritis?
circulating
ANCA!
(pauci-ANCA = paul anka)
what ANCA is assoc w/ Wegener?
PR3-ANCA
c-ANCA
what ANCA is assoc w/ microscopic polyangiitis?
MPO-ANCA
p-ANCA
what ANCA is assoc w/ Churg-Strauss?
p-ANCA
what causes most cases of type III rapidly progressive glomerulonephritis?
most cases are idiopathic
what is the treatment for type III rapidly progressive glomerulonephritis?
steroids
cytotoxic agents
what are the 4 things you need to remember about nephrOtic syndrome?
- massive proteinuria
- hypoalbuminemia (& hypogammaglobulinemia)
- edema
- hyperlipidemia / hypercholesterolemia
(Pathoma says also loss of ATIII)
T/F: proteinuria in nephrotic syndromes can be selective
TRUE
what are the 2 MAIN/broad causes of nephrotic syndromes?
primary glomerular disease
AND
systemic disease
what are the 5 primary glomerular diseases that can be nephrotic?
- MCD
- FSGS
- MN
- MPGN
- DM
- SA
what is the most frequent cause of nephrotic syndrome in kids?
MCD
what does MCD look like on H&E?
normal glomeruli
what does MCD look like on IF?
negative/normal (no immune complexes)
what does MCD look like on EM?
effacement of foot processes of podocytes
what do MCD & FSGS have in common?
no immune complex deposition so negative IF
effacement of foot processes on EM
what is the biggest diff btwn MCD & FSGS?
FSGS has focal segmental glomerular sclerosis on H&E (hence the name)
what is the pathophysiology of MCD?
immune dysfxn > cytokine > damage to visceral epithelial cells > proteinuria
what is MCD assoc w/?
respiratory illness
post-immunization
atopic disorders
what nephrotic syndrome can you give steroids to treat?
MCD only!
what cancer is MCD assoc w/?
Hodgkin lymphoma
T/F: MCD has highly selective proteinuria
TRUE
selective for albumin
T/F: MCD is assoc w/ HTN & hematuria
FALSE
MCD is nephrOtic
HTN & hematuria are nephritic sx
what age group is affected by membranous nephropathy?
adults
which 2 nephrotic syndromes are immune complex mediated?
membranous nephropathy
AND
membranoproliferative glomerulonephritis
T/F: there is only primary membranous nephropathy
FALSE
primary & secondary
what characterizes membranous nephropathy?
diffuse thickening of the glomerular capillary wall
thickened glomerular BM
does membranous nephropathy have Ig deposits?
YES
subepithelial > spike & dome
what does membranous nephropathy look like on H&E?
thickened glomerular BM
what does membranous nephropathy look like on IF?
granular d/t immune complexes
what does membranous nephropathy look like on EM?
spike & dome d/t subepithelial deposits
what are the 3 clinical features of membranous nephropathy?
- insidious onset
- mild HTN & hematuria possible
- progression leads to glomerular sclerosis
what is the treatment for membranous nephropathy?
treat underlying condition
does NOT respond to steroids
what is FSGS characterized by?
focal & segmental sclerosis of the capillary tuft
what are the 4 possible causes of FSGS?
- idiopathic
- secondary
- complication of focal glomerulonephritis
- adaptive response to loss of renal tissue
what is FSGS thought to be a part of clinically & why?
thought to be a phase in MCD
accentuated diffuse epithelial cell change of MCD
cytokine-mediated or defects in slit diaphragm proteins
T/F: you get hyalinosis & sclerosis w/ FSGS
TRUE
d/t entrapment of plasma proteins
what does FSGS look like on H&E?
focal segmental sclerosis
what does FSGS look like on EM?
effacement of foot processes
what does FSGS look like on IF?
negative/normal (bc no immune complexes)
T/F: idiopathic FSGS spontaneously remits
FALSE
“little tendency”
does FSGS respond to steroids?
variable (poor)
what are the sx of MPGN (generally)?
- nephrotic sx
- nephritic sx
- nephritic-nephrotic sx
- asymptomatic hematuria
what characterizes MPGN?
- altered GBM
- proliferation of glomerular cells/mesangium
- leukocyte proliferation
T/F: there is only one type of MPGN
FALSE
there are 2!
what is type I MPGN?
immune complex deposition + activation of classical & alt complement pathways
what can cause type I MPGN?
planted exogenous ag (HBV & HCV)
circulating immune complexes
where are the deposits in type I MPGN?
subendothelial
where are the deposits in type II MPGN?
intramembranous
is type I or type II MPGN more common?
type I
what is type II MPGN?
dysregulation of alt complement pathway
what is the pathophysiology of type II MPGN?
auto-ab (C3 nephritic factor) that stabilizes C3 convertase > overactivates complement > low circulating C3 + inflammation
what does MPGN look like on H&E?
thickened glomerular BM w/ tram-track appearance
T/F: most cases of MPGN spontaneously remit
FALSE
few spontaneous remissions w/ a slowly progressive & unremitting course
T/F: steroids & immunosuppressives are the RX for MPGN
FALSE
what is the most common type of glomerulonephritis worldwide?
IgA nephropathy
how do IgA nephropathy pts present?
w/ recurrent episodic gross or microscopic hematuria (episodes coincide w/ mucosal [resp or GI] infections)
what is the systemic form of IgA nephropathy?
Henoch-Schonlein purpura
where does the IgA immune complex deposit in IgA nephropathy?
mesangium
what form of IgA increases in IgA nephropathy?
polymeric forms of IgA1
what causes IgA nephropathy?
genetic or acquired abnormality of immune regulation upon exposure to env agents in lungs & GI tract
how does IgA nephropathy cause glomerular injury?
IgA & immune complexes get trapped in the mesangium > activate complement > injury
what does IgA nephropathy look like on IF?
granular d/t IgA immune complex deposition
T/F: IgA nephropathy pts may retain renal fxn for decades
TRUE!
what can diabetic nephropathy cause?
kidney failure (one of the leading causes)
what 3 glomerular syndromes is diabetic nephropathy assoc w/?
- non-nephrotic proteinuria
- nephrotic syndrome
- chronic renal failure
what are the 3 manifestations of diabetic nephropathy?
- hyalinizing arteriolar sclerosis
- pyelonephritis
- tubular lesions
what does diabetic nephropathy look like on H&E?
Kimmelstiel-Wilson nodules (sclerosis) = pathognomonic
what is Alport syndrome?
X-linked inherited defect in type IV collagen
what 3 things characterize Alport syndrome?
- hematuria progressing to renal failure
- sensory hearing loss
- ocular disorders
what is familial renal disease (Alport) d/t?
defects in type IV collagen
how does familial renal disease (Alport) clinically manifest?
familial asymptomatic hematuria
what is the prognosis for familial renal disease (Alport)?
normal renal fxn
excellent prognosis
what is the kidney lesion in familial renal disease (Alport)?
thinned & split glomerular BM