Nephrotic Syndrome: Minimal change disease/Nil Disease

Question 1

Epidemiology + Risk factors

Answer 1

Most common cause of nephrotic syndrome in children
Associated with Hodgkin lymphoma

Question 2

Pathophysiology

Answer 2

Podocyte repel -ve charged molecules e.g. albumin = charged barrier
In MCD = T cells in blood release cytokines that damage the foot processes of podocytes = EFFACEMENT = lessens the charged barrier
The damaged glomeruli become more permeable so start letting plasma proteins come across from blood to the nephrons then urine = proteinuria (> 3.5g per day) = hypoalbuminemia
-> less protein in the blood the oncotic pressure falling = lowers the overall osmotic pressure = drives water out of blood vessels = oedema
As a result of losing albumin = increased levels of lipids in blood = hyperlipidaemia. Which can also get into the urine = lipiduria

Question 3

Hallmark factors

Answer 3

• Proteinuria > 3.5g/day
• Hypoalbuminaemia (30 g/L) which leads to oedema
• Hyperlipidaemia
• Hypogammaglobulinemia: due to loss of immunoglobulin in the urine
• Hypercoagulability: due to loss of antithrombin III, and protein C and S in the urine

Question 4

Aetiology

Answer 4

Most often idiopathic but can be triggered by:
- recent infection
- recent vaccination
- by an immune stimulus e.g. bee sting

Question 5

Signs and symptoms

Answer 5

Symptoms
- Frothy urine
- Facial and peripheral oedema
- Recurrent infections: due to hypogammaglobulinaemia
- Increased risk of VTE: due to hyper-coagulability
Signs
- HTN
- Proteinuria
- Limited or absent haematuria

Question 6

Diagnosis (E for E)

Answer 6

Primary investigations:
- Urinalysis: Proteinuria
- 24 hour urine protein collection > 3.5g
- Urine albumin-creatinine ratio (ACR)
- LFT’s: hypoalbuminaemia < 25g/L
- Lipid profile: hypercholaestrolaemia
- USS Renal
Consider: Renal biopsy
- Light microscopy: normal glomeruli on light microscopy
- Electron microscopy (EM): effacement of foot processes
- Immunofluorescence with minimal change disease usually negative, since the damage is due to cytokines = not immune complex deposition

Question 7

Treatment

Answer 7

• Corticosteroid therapy
• children respond really well
• adults respond slower
  e.g. PREDNISOLONE
• Diuretics: symptomatic relief of fluid overload