14 - Glomerular Pathology Flashcards
If the following terms were used to describe the kidney on a histology report, what would they mean?
What are the diffferent regions you can see histologically when looking at a glomerulus?
Label this electron microscopy of the glomerulus?
Basement membrane dark as negatively charged so lots of electrons
What is nephrotic syndrome?
- Proteinuria >350mg.mol or 3.5mg in 24 hours
- Hypoalbuminaemia
- Oedema
- May also have hyperlipidaemia as compensatory synthesis of albumin in the liver raising lipid levels
- GFR and B.P relatively normal
What is nephrotic range proteinuria?
Proteinuria >350mg/mol but no other features of nephrotic syndrome, common with diabetic nephropathy
Why do you get the triad of symptoms in nephrotic syndrome?
Insult to filtration barrier, often podocyte or subepithelial
- Proteinuria and Hypoalbuminaemia: loss of selective barrier and can’t be resorbed in tubules
- Oedema: loss of oncotic pressure in capillaries as loss of albumin so fluid leak into ECF. also, loss of fluid to ECF stimulates RAAS but low oncotic pressure so more fluid leaks, RAAS restimulated so constant cycle and chronic salt retention
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Where are the different areas that pathology can occur in the glomerulus?
Can be due to injury, infections, immune complex deposition
What are some of the common causes of nephrotic syndrome?
Primary:
- Minimimal change disease
- Focal segmental GS
- Membranous GN (odd one out)
Secondary:
- Diabetic nephropathy
- SLE
- Renal amyloidosis
What are the characteristics of minimal change disease and what does it look like histologically?
- Common in childhood and can lead to nephroic syndrome
- Responds to steroids, may reoccur but doesn’t really lead to renal failure
- Can only see change on electron microscopy where foot processes are wiped out
- Don’t know the pathogenesis, something circulating
What are the characteristics of focal segmental glomerulosclerosis and what does it look like histologically?
- Mainly adults and can lead to nephrotic syndrome
- Thickening of basement membrane as scarring (glomerulosclerosis)
- Leads to renal failure
- Decrease GFR
What are the characteristics of memrbranous glomerulonephritis and what does it look like histologically?
- Commonest cause of primary nephrotic syndrome in adults
- Rule of thirds
- Immune complex deposits in subepithelia (often against GBM) and can be secondary with infection and lymphoma
- Thicker glomerular membrane with IgG and spikey membrane
What is nephritic syndrome?
- Haematuria
- GFR reduction so oliguria
- Hypertension
Often pyuria, erythrocyte casts in urine, oliguria and azotemia
CAUSED BY AN INFLAMMATORY PROCESS
Why do we get erythrocyte casts in the urine during nephritic syndrome?
Inflammation injuries the glomerular capillaries so erythrocytes and proteins can leak into urine and the RBC’s then may aggregate in the tubule and take it’s shape
Why do you get a reduced GFR in nephritic syndrome?
- Glomeruli full of cells and proteins from inflammation/damage, compressing the capillaries so less fluid can filter through
- Damage to glomeruli so decline in GFR leading to oliguria and secondary hypertension as renin released
What are some causes of nephritic syndrome?
- Acute proliferative GN
- IgA Nephropathy
- Goodpasture syndrome
- Rapidly progressive GN
- Alport syndrome
- Lupus Nephritis
- Vasculitis
What are the characteristics of IgA nephropathy and what does it look like histologically?
- Commonest GN
- Usually haematuria and has a relationship with mucosal infections
- +/- proteinuria
- Most progress to renal failure
- No effective treatment just manage symptoms
IgA DEPOSIT IN MESANGIUM AND CAPILLARY WHICH ACTIVATES IgG AND CAUSES DESTRUCTION AS MESANGIAL PROLIFERATION AND MATRIX PROLIFERATION
What are the characteristics of inherited nephropathies that can lead to nephritic syndrome?
- Thin GBM disease: isolated haematuria, thin GBM and doesn’t progress
- Alport: X-linked collagen IV. Abnormal GBM and progresses to renal failure
What is ANCA glomerulonephritis?
- When ANCA vasculitis involves the kidneys and causes nephritic syndrome
- No immune complex deposition
- Treatable if caught early so need urgent biopsy as renal failure is quick
- SEGMENTAL NECROSIS AND CRESCENT SHAPE
What are the layers of the filtration membrane in the glomerulus?
What is the role of the juxtoglomerular granular cells?
