Nephrotic syndrome (URO) Flashcards
Define nephrotic syndrome.
Defined as the presence of proteinuria (>3.5g/24h), hypoalbuminaemia (<30g/L) and peripheral oedema
What is nephrotic syndrome?
Collection of signs and symptoms indicating damage to the glomerular filtration barrier
What is nephrotic syndrome characterised by? (3)
- massive proteinuria (>3.5g/24hr)
- hypoalbuminaemia (<30g/L)
- peripheral oedema
What causes proteinuria in nephrotic syndrome?
Glomerular damage (injury to podocytes) causes protein leakage into urine
This proteinuria –> hypoalbuminaemia and subsequent oedema due to reduced plasma oncotic pressure
How can nephrotic syndrome be classified?
Primary (idiopathic) or secondary to systemic disease
What are some causes/examples of nephrotic syndrome? (5)
- minimal change disease (primary)
- membranous glomerulonephritis (primary) AKA membranous nephropathy
- focal segmental glomerulosclerosis (primary)
- diabetic nephropathy (secondary)
- amyloid nephropathy (secondary)
In which groups is minimal change disease (nephrotic syndrome) the most common cause of nephrotic syndrome?
Children (young <10)
What does minimal change disease (nephrotic syndrome) commonly present with?
Peri-orbital oedema
What diseases is minimal change disease (nephrotic syndrome) associated with? (3)
- URTI
- non-Hodgkin’s lymphoma
- secondary to Hodgkin’s lymphoma
Describe the pathophysiology of minimal change disease (nephrotic syndrome).
Cytokine-mediated damage of podocytes (role is to prevent protein entering filtrate) - they lose their negatively-charged coat –> proteinuria
What will light microscopy show in minimal change disease (nephrotic syndrome)?
Normal light microscopy
Why is it called ‘minimal change disease’ (nephrotic syndrome)?
‘Minimal change’ refers to light microscopic findings that often reveal normal glomeruli or mild mesangial proliferation with negative immunofluorescence and no immune complex deposition
What will electron microscopy show in minimal change disease (nephrotic syndrome)?
Fusion of podocytes
What is the cause of minimal change disease (nephrotic syndrome)?
Often idiopathic
Describe the clinical picture of minimal change disease (nephrotic syndrome).
Fully nephrotic
What is minimal change disease (nephrotic syndrome) typically responsive to?
Steroids
How do we manage minimal change disease (nephrotic syndrome)?
- prednisolone (corticosteroids) and gradually increase dose
- if resistant to prednisolone –> cyclophosphamide (immunosuppressants)
In which group is membranous glomerulonephritis/nephropathy (nephrotic syndrome) the most common cause of nephrotic syndrome?
Most common cause in older adults
Describe the pathophysiology of membranous nephropathy (nephrotic syndrome).
Deposition of immune complexes on basement membrane –> damage to podocytes and mesangial cells
What diseases is secondary membranous nephropathy (nephrotic syndrome) commonly associated with? (4)
- malignancy
- SLE (lupus nephritis)
- hepatitis B&C
- autoimmune disease
What would a renal biopsy of membranous nephropathy (nephrotic syndrome) show under light microscopy?
Basement membrane thickening (without associated cellular proliferation or infiltration)
What would a renal biopsy of membranous nephropathy (nephrotic syndrome) show under electron microscopy?
Spike and dome appearance
Which antibodies is primary membranous nephropathy (nephrotic syndrome) associated with?
Anti-phospholipase A2 receptor antibodies (PLA2R)
What other blood result might we see in membranous nephropathy (nephrotic syndrome)?
Low T4