Nephrotic syndrome Flashcards
What is nephrotic syndrome?
Collection of signs and symptoms indicating damage to the glomerular filtration barrier
- “HOP”: hyopalbuminaemia (body doesn’t produce enough albumin protein that’s responsible for keeping fluid in your blood vessels), oedema, proteinuria.
What is meant by primary nephrotic syndrome?
Direct sclerosis of podocytes (specialised epithelial cells that coat the outer walls of glomerular capillaries- role is to prevent protein entering filtrate) on the glomerulus
What are the 3 different primary nephrotic syndromes?
- Minimal change disease
- Focal segmental glomerulosclerosis
- Membranous nephropathy
What is Minimal change disease?
- Associated with URTI
- Cytokine mediated damage of podocytes (role is to prevent protein entering filtrate)
- Most common cause in children → commonly presents with peri-orbital oedema
- Often idiopathic. Associated with non-hodgkin’s lymphoma.
What findings point to minimal change disease, and how is it treated?
- Light Microscopy = normal.
- Electron Microscopy = fusion of podocytes.
- Immunofluorescence= negative
Tx: prednisolone (it is the only nephrotic disease that can consistently be treated with corticosteroids)
What is Focal segmental glomerulosclerosis?
- Sclerosis of glomeruli ⇒ damage and loss of podocytes
- Common in afro-carribean population
- Associated with obesity, diabetes, HIV, heroin use, sickle cell
What findings point to Focal segmental glomerulosclerosis, and how is it treated?
- Renal biopsy would show focal segmental areas of mesangial collapse and sclerosis on light microscopy
- Electron Microscopy ⇒ effacement of foot processes of podocytes
- Immnofluorescence= often negtaive, sometimes positive for deposits C3, C1 or IgM
Tx: corticosteroids, BUT inconstant response to corticosteroids
- may progress to chronic kidney disease
What is Membranous nephropathy?
Most common cause in adults → deposition of immune complexes on basement membrane
- Commonly associated with malignancy, SLE, hep B/C, autoimmune disease
- Low response to steroids
What findings point to membranous nephropathy?
- Renal Biopsy ⇒ GBM (glomerular basement membrane) thickening (Light Microscopy) and Spike and dome appearance (Electron Microscopy)
- Anti-phospholipase A2 receptor antibodies (anti-PLA2R antibodies)
- Immunoflurescence: immune complexes are granular -> IgG & C3
What is meant by secondary nephrotic syndrome?
damage secondary to a systemic disease
What are the 2 secondary nephrotic syndromes?
- Diabetic glomerulonephropathy
- Amyloid nephropathy
What is diabetic glomerulonephropathy?
- The increased glucose in the blood
- Increases the glomerular filtration rate
= hyperfiltration - This puts an increased pressure in the glomerulus = damage/ leaks out of the basement membrane
- Usually additional signs of retinopathy and neuropathy
What findings point to diabetic nephropathy and how is it treated?
- Light Microscopy ⇒ mesangial expansion, GBM thickening, Kimmelstiel-Wilson nodules.
- Mx with diabetic control and ACEi/ARB
What is amyloid nephropathy?
- Deposition of amyloid in kidney: proteins with an abnormal shape stick together & settle in tissues
- Most commonly seen in elderly patients
- Associated with multiple myeloma or chronic inflammatory disease (TB or RA)
- Kidney is most commonly affected organ in systemic amyloidosis
What findings point to amyloid nephropathy?
Congo red staining = apple-green birefringence
