Nephrotic Syndrome

Question 1

Define nephrotic syndrome

Answer 1

Characterised by:
• Proteinuria >3g/24h
• Hypoalbuminaemia <30g/L
• Oedema
• (Hyperlipidaemia)

Question 2

What are the causes/risk factors of nephrotic syndrome?

Answer 2

Structural damage to glomerular basement membrane -> large proteins in urine -> proteinuria and hypoalbuminaemia

Hypoalbuminaemia
• low oncotic pressure of blood -> fluid extravasation into tissues -> oedema
• compensatory increased liver function -> hyperlipidaemia and hypercoagulability

Causes
• Minimal change disease
- Loss of podocyte foot processes
- Most common in children
• Focal segmental glomerulosclerosis
- Focal GBM thickening/ scarring/sclerosis
- Young adults
- Primary: idiopathic
- Secondary: HIV, obesity
• Membranous nephropathy
- GBM thickening from IgG deposition, cellular proliferation/infiltration
- Older adults
- Primary: idiopathic
- Secondary: hepatitis B, SLE, malignancy, drugs (gold, penicillamine, NSAIDs)
• Diabetic nephropathy
• Amyloidosis

Question 3

What are the symptoms of nephrotic syndrome

Answer 3

• Swelling (legs, abdomen, face, genitalia)

* Foamy urine

Question 4

What are the signs of nephrotic syndrome?

Answer 4

• Oedema (periorbital, peripheral, genital)

* Ascites – fluid thrill, shifting dullness

Question 5

What investigations are carried out for nephrotic syndrome?

Answer 5

• LFTs - hypoalbuminemia (< 30g/L)
• ESR/ CRP - may be elevated in inflammatory causes.
• Lipid Profile - hyperlipidaemia and hypercholesterolaemia.
• Identify the cause - SLE: ANA, anti-dsDNA.
- Infections: Group A b-haemolytic streptococcal infection, HBV infection (serology), plasmodium malariae (blood films).
- Goodpasture’s syndrome: Anti-glomerular basement membrane (GBM) antibodies.
- Vasculitides: Wegener’s and microscopic polyarteritis (ANCA).
• Urinalysis - haematuria and Proteinuria
• 24 hr Urine - proteinuria (>3g/24 hrs).
• Spot urine sample - protein: Creatinine Ratio (PCR) > 300mg/micromole is diagnostic of NS. Being used way more often.
• Renal USS - excludes other renal diseases that may cause proteinuria, e.g. reflux nephropathy.
• Renal Biopsy - in all adults and in children who have unusual features or do not respond to steroids
• Other - if renal vein thrombosis is suspected: Doppler USS, renal angiogram, CT and MRI