Diabetic nephropathy

Question 1

Define nephrotic syndrome

Answer 1

Nephrotic syndrome is a group of renal symptoms that can be caused by several renal diseases. Defining criteria are:

• Proteinuria (>3.5g/24hrs)
• Hypoalbuminaemia (<30g/L)
• Peripheral oedema

Question 2

List some causes of nephrotic syndrome

Answer 2

• Minimal change disease (often children)
• Focal segmental glomerulonephritis (younger adults)
• Membranous nephropathy (older adults)
• Diabetic nephropathy
• Amyloidosis (primary or secondary e.g. multiple myeloma)
• IgA nephropathy
• Other rarer causes

Question 3

Bilateral leg swelling DDx?

Answer 3

• Heart disease
• Liver disease
• Renal disease
• Pretibial myxoedema - hypo/hyperthyroidism
• Lymphoedema causes?
• Bilateral DVT
• Iatrogenic - drug S/E e.g. Ca channel blockers

Question 4

Why do you get hypercoagulability in nephrotic syndrome?

Answer 4

Loss of anticoagulation proteins in the urine

Question 5

Why do you get hyperlipidaemia in nephrotic syndrome?

Answer 5

Liver increases albumin synthesis to compensate for hypoalbuminaemia, and creates other molecules e.g. LDL, VLDL and lipoprotein as well.

Question 6

Identify the main features and function of the glomerular filtration barrier

Answer 6

From inside to out:
- Fenestrated endothelium
- Glomerular basement membrane (-ve charge)
- Foot processes of podocytes forming a slit diaphragm
> Main filtration mechanism (-ve charge and size)
- Mesangial cells lie between the capillaries and provide glomerular structure

Question 7

Why is there peripheral oedema in nephrotic syndrome?

Answer 7

Reduced intravascular oncotic pressure disturbs usual balance of net oncotic and net hydrostatic pressure. Water goes into interstitial tissues accordingly.