Nephrotic Syndrome Flashcards
What is Nephrotic syndrome characterized by?
- > 3.5 g massive proteinuria/day which causes (foamy urine)
- hypoalbuminaemia (usually <2.5g/dl or 25g/l) because albumin is usually the most abundant protein in the blood
- Generalized Oedema from salt and water retention (including facial swelling in children)
- +/_ dyslipidaemia
- +/- Lipiduria
What is the Epidemiology of nephrotic syndrome?
The incidence of nephrotic syndrome worldwide has been estimated to be about 3 new cases per 100,000 per year.
Incidence /prevalence of adult nephrotic syndrome in Nigeria is unknown as there is no registry data available, but nephrotic syndrome is not an uncommon disease in Nigerian adult population.
Specific investigations in NS
Hepatitis B & C, HIV
Filariasis
Tests for Conn Tiss Dx
Tests when clinically relevant e.g:
For vasculitis (ANCA)
For PSGN (rare in adults)
Tests are done to exclude what?
Tests to Exclude
Diabetes – diagnosis
Myeloma
Lymphoma
Cancers
Other investigations in NS
Which investigation would not be helpful?
What does a CT scan exclude?
- Imaging
* X-ray chest (can view pleural effusion and oedema)
* CT scan e.g. to exclude lymphoma etc. (EUG, Ultrasound NOT helpful) - Renal Biopsy: I) light microscopy looks at the general change in kidney tissue II) Immunofluorescence III) electron microscopy
Indications for renal biopsy
Persistent Proteinuria
Persistent Macroscopic haematuria (of glomerular aetiology)
Nephrotic syndrome
Unexplained:
-ARF
-CRF (with normal sized kidneys)
Allograft dysfunction
General management measures of NS
- Dietary sodium restriction: to reduce fluid retention and oedema
- Diuretics: Nephrotic patients may malabsorb diuretics (as well as other drugs) due to gut mucosal edema
- Normal protein diet is advisable. A high-protein diet increases proteinuria and can be harmful in the long term, whereas a low-protein diet can lead to malnutrition.
- Albumin infusion produces only a transient effect. It is only given to patients who are diuretic-resistant
*Anticoagulation: NS increases the risk of thromboembolism due to hypercoagulability due to loss of anticoagulant proteins in urine, increased platelet aggregation, venous stasis due to edema
- Antibiotics if Sepsis: NS patients are are higher risk of infections
- Statins (to lower cholesterol): due to hyperlipidemia
- ACE inhibitors and/or angiotensin II receptor antagonists
Specific management measure of NS
Treat the underlying cause
Primary causes of nephrotic syndrome
- Minimal change nephropathy; (commonest cause of primary GN in children): no hematuria
- Congenital nephrotic syndrome
- Focal (some glomeruli) segmental (parts of individual glomuerulus) glomerular sclerosis: scarring of the glomeruli (FSGS has almost identical symptoms to MCD but it’s more in adults): has hematuria
- Membranous nephropathy: thickening of basement membrane
Secondary causes of nephrotic syndrome
Amyloidosis: deposition and accumulation of amyloid in tissues
Diabetic nephropathy
Pathophysiology
- Inflammations and damage to the glomerulus causes specifically to podocytes which normally help prevent protein loss
- Allowing proteins to pass through to the nephrons tubule and into urine
- This loss of protein causes hypoalbuminemia which causes the liver to produce protein to compensate but also cholesterol causing hyperlipidemia
- The hyperalbuminemia also reduces plasma osmotic pressure, causing water and electrolytes to live into the interstitium (surrounding tissues) causing edema
- This also triggers RAAS causing retention of salt and water
- Hypercoagulability is due to loss of anti-thrombin III in urine. Causing predisposition to DVT and PE, arterial thrombosis eg. MI and stroke
Investigation of glomerular diseases
Urine microscopy: Red cells, red-cell casts
Urinary protein: Nephrotic or sub-nephrotic-range proteinuria
Serum urea: May be elevated
Serum creatinine: May be elevated
Culture (throat swab, discharge from ear, swab from inflamed skin): Nephritogenic organism (not always)
Anti-streptolysin-O titre: Elevated in post-streptococcal nephritis
C3 and C4 levels: May be reduced
Antinuclear antibody (ANA): Present in significant titre in systemic lupus erythematosus
Antinuclear cytoplasmic antibody (ANCA): Positive in some vasculitides
Anti-glomerular basement membrane (anti-GBM): Positive in Goodpasture syndrome
Cryoglobulins: Increased in cryoglobulinaemia
Chest X-ray: Cardiomegaly, pulmonary oedema (not always)
Renal imaging: Usually normal
Renal biopsy: Any glomerulopathy
