Nephrotic Syndrome Flashcards
What is the common pathogenesis in nephrotic syndrome?
Derangement in capillary wall of glomeruli, resulting in inc permeability to PPs leading proteinuria
Describe mechanism of edema in nephrotic syndrome
Dec oncotic pressure due to proteins loss so fluid escapes from vascular tree into tissues, there is concomitant drop in plasma volume with diminished glomerular filtration volume. This leads to inc renin which promotes salt & water retention aggravating edema.
What is the fause of hyperlipidemia in nephhrotic $
- Hypoalbuminemia triggers inc synthesis of lipoproteins in the liver
- Abnormal transport of circulating lipid particles
- Impairment of peripheral breakdown of proteins
List microscopic features of tubules & interstitial tissue in nephrotic sydrome
- Hyaline droplet degeneration of the epithelium of the convoluted tubules due to resorption of protein from the urine
- Vacuolar degeneration of the epithelium of the convoluted tubules due to resorption of lipids from urine
- Protein casts within tubular lumen
IT shows variable edema
Common EM feature of nephrotic syndrome is……
Effacement of foot processes of the podocytes
The most common cause of nephrotic syndrome is…….most common in age…….
Minimal change disease
1-7 yrs
Describe pathogenesis of minimal change disease
Attributed to a circulating T-cell derived factor that causes podocyte damage and effacement of foot processes.
Minimal change disease microscopic changes can only be seen by……
EM
Describe C/P & prognosis of minimal change disease
Nephrotic syndrome with highly selective albuminuria
Good prognosis is good, particularly in children, with prolonged remission or even permenant cure occur spontaneously or in response to steroid therapy. Adults show more frequent relapses, only rare cases lead to chronic renal failure.
Etiology of FSGS?
- Primary (idiopathic)
- 2ry to HIV infection, or to other causes of GN as IgA nephropathy or 2ry to hyperfiltration injury or due to maladaptation to nephron loss
What is pathogenesis of FSGS?
It is unknown, injury to podocytes is thought to represent the initiating event of primary FSGS, in minimal change disease a circulating permeability inc factors produced by lymphocytes are suspected. The deposition of hyaline masses in the glomeruli represents the entrapment of PPs & lipids in foci of injury where sclerosis develops.
Describe LM features of FSGS
- Presence of sclerotic segments in a variable number of glomeruli
- Affected glomeruli exhibit inc mesangial matrix, obliterated capillary lumina and deposition of hyaline & foamy macrophages
- Tubules & interstitial tissue exhibit variable tubular atrophy & interstitial fibrosis
Describe clinical course of FSGS
Nephrotic syndrome presentation or nephrotic/nephritic syndrome (HTN & hematuria), proteinuria is non-selective may be in subnephrotic range
It is resistant to steroid 50% or more develop end stage renal disease within 10 yrs of diagnosis
Describe pathogenesis of membranous glomerulonephritis
- It is a form of chronic immune complex GN induced by antibodies reacting in situ to fixed (1ry disaese, podocyte antigen phospholipase A2 receptor (PLA2R) or planted (2ry disease, endogenous or exogenous Ag
- This activates MAC causing podocyte injury & proteinuria, also stimulates TGF receptor on Ep cells inc synthesis of GBM materal leading to thickening of GBMs
Describe findings of EM & immunofluorescence in MGN
IFM: granular deposits of IgG & complement along the GBM
EM: reveals subepithelial electron dense deposits separated by outward projections of the GBM termed spikes. As the disease progresses the spikes incorporate into GBM (intramembranous), diffuse fusion of foot processes of podocytes, in more advanced stage there is actual thickening of GBM with disappearance of deposits.