Nephrotic Syndrome Flashcards
How does blood enter the glomerulus?
It enters the glomerulus via an afferent arteriole
The blood is under high pressure
How is filtrate formed in the Bowman’s capsule?
Fluid passes across the walls of the capillary and the nephron and into the capsule
Why is it significant that the pressure is high in the afferent arteriole?
Fluid needs to be forced out of the glomerulus and into the Bowman’s capsule to form the ultrafiltrate
What is the capillary hydrostatic pressure and the Bowman’s capsule hydrostatic pressure?
Capillary - 45 mmHg
Bowman’s capsule - 10 mmHg
What is the plasma protein oncotic pressure in the tubule?
What is significant about this?
25 mmHg
Once the fluid is in the tubule, it keeps it there and prevents it from leaving
It draws fluid towards the tubule
What are the layers of the glomerular filtration barrier?
From the interior of the Bowman’s capsule:
- epithelial foot process
- slit membrane
- basement membrane
- endothelial cells of the capillary (fenestra between them)
Capillary lumen
What are the 3 layers of the basement membrane?
- lamina rara
- lamina densa
- lamina rara
What is the main function of the glomerular filtration barrier?
It prevents proteins from leaking into the urine
How is the urine modulated in nephrotic syndrome?
There is loss of protein in the urine
This is proteinuria
What is hypoalbuminaemia in nephrotic syndrome?
This involves the level of albumin in the blood being abnormally low
What is the consequence of losing protein in the urine?
Oedema
This results due to a loss of oncotic pressure
What is the consequence of having low plasma albumin?
The liver increases its production of cholesterol
This leads to hypercholesterolaemia
What causes the loss of protein in urine in nephrotic syndrome?
Injury to the epithelial foot processes of the nephron
What is the most common cause of nephrotic syndrome in children?
Minimal change disease
What are the most common causes of nephrotic syndrome in adults?
- membranous nephropathy
- focal segmental glomerulosclerosis
- amyloid
What happens to the foot processes in nephrotic syndrome?
They become flattened and collapsed
There is loss of the filtration slits
What is the main treatment of nephrotic syndrome?
Potent Immunosuppressants
e.g. steroids, cyclophoshamide, rituximab, plasma exchange, azathioprine
What is the risk of giving potent immunosuppressants to patients?
They are more prone to infection
What causes CRP to increase?
Bacterial infection and inflammation
e.g. cancer promotes an inflammatory response
How can amyloid be identified through staining?
It shows apple green birefringence in polarised light
With Congo Red stain
What is amyloid usually secondary to?
Myeloma
