11.3 Nephrotic Syndrome

Question 1

How might functional proteinuria come about?

Answer 1

• increased blood flow to nephron causes increased protein filtration
• Can occur in conditions such as heart failure, exercise, and fever

Question 2

Diagnostic triad of nephrotic syndrome (incl. numbers). Also mention others

Answer 2

• Hypoalbuminaemia (<30mg/L)
• Proteinuria (> 3.5g/day)
• Oedema

Others:
- Hypercoagulability
- Hyperlipidaemia
- Low nitrogen balance

Question 3

Describe the two hypothesised mechanisms of oedema formation in nephrotic syndrome

Answer 3

• Underfill: low oncotic means lkow blood volume, which means RAAS activation
• Overfill: starts with increased retention of sodium and water, leading to transudation

Question 4

Nephrotic syndrome can cause hyperlipidaemia due to increased hepatic lipoprotein synthesis. Give two examples of clinical signs that can indicate this

Answer 4

• Xanthelasma
• Lipiduria (frothy)

Question 5

How does nephrotic syndrome affect coagulability and nitrogen balance?

Answer 5

• Hypercoagulable (inc synthesis thrombotic, dec synthesis antithrombotic)
• Negative nitrogen balance (can cause loss of function)

Question 6

How is nephrotic syndrome diagnosed

Answer 6

• Can be detected w/ clinical presentation and lab features
• With kids, give steroids for “exquisite” effect; most have minimal change disease
• In adults, give biopsy to determine underlying cause

Question 7

In which demographic is minimal change disease more common?

Answer 7

Children and young adults

Question 8

Pathogenesis of minimal change disease

Answer 8

• Effacement of podocytes; glomerulus is minimally changed
• Mechanism not exactly clear, postulated that T cell autoreaction is involved

Question 9

Clinical features of minimal change disease and membranous nephropathy

Answer 9

Same as nephrotic syndrome (what are they?)

Question 10

Management of nephrotic syndrome

Answer 10

• Oedema: diuretics + reduced sodium intake (careful to avoid hypovolaemia)
• Anticaogulation may be indicated
• Statin to reduce hyperlipidaemia
• ACEi/ARB to reduce hypertension (CKD) and anti-proteinuric due tor lower filtration pressure

Question 11

Management of minimal change disease?

Answer 11

Corticosteroids (reduce swelling)

Question 12

Management of membranous nephropathy

Answer 12

• Corticosteroids
• Rituximab (targets B cells)
• Calcineurin inhibitors

Question 13

Pathogenesis of membranous nephropathy. What are some proposed secondary causes

Answer 13

• Autoimmune condition involving phospholipid A2 receptor autoantibodies (receptor found on podocytes)
• Characterised by subepithelial deposits and GBM thickening
• 2° causes incl. Lupus and malignancy

Question 14

What is the histopathological basis for nephrotic syndrome?

Answer 14

• Increased GBM permeability and decreasd effectivenes of podocyte layer barrier
• Causes proteinuria and thus oedema etc.

Question 15

Does/how does nephrotic syndrome influence coagulation?

Answer 15

Nephrotic syndrome causes HYPERcoagulability.