nephrotic syndrome Flashcards
Major features of nephrotic syndrome?
- MASSIVE PROTEINURIA (greater than 3.5 g in 24 hrs) which leads to:
HYPOALBUMINEMIA (less than 3) which leads to peripheral EDEMA because drop in oncotic pressure in vasculature so fluid leaks into surrounding tissue - HYPERLIPIDEMIA: liver is making more proteins
- thrombotic disease
- few cells or casts in urine
Major features of nephritic syndrome?
- Lesions that cause increased cellularity w/in glomeruli, along with leukocytic infiltrate. The INFLAMMATION injures cap walls, permitting escape of RBCs into urine. This leads to decreased GFR (oliguria and azotemia). HTN result of fluid retention and increased renin released from ischemic kidneys
Key features
- RED CELL CASTS
- oliguria
- azotemia
- HTN
Incidence of nephrotic syndrome?
- children: 2:100,000 new cases/year
primarily: MCD - adults: 3:100,000 new cases/year, variety of etiologies
Etiologies of nephrotic syndrome?
- adults: Systemic diseases such as DM, amyloidosis, HIV, and SLE
- NSAIDs
- MCD
- SFG
- membranous nephropathy
children: minimal change disease predominant cause
Pathophys of nephrotic syndrome?
- the glomerular cap wall: electrostatically prevents negatively charged proteins from passing through, podocyte intercellular jxns restrict the passage of proteins of certain sizes - most nephrotic diseases there is damage to GCW and this results in the loss of charge - proteins will pass through and aso damage to podocytes - allows larger proteins to pass
–massive proteinuria leads to decrease in plasma proteins which leads to fluid shift out of vasculature so decreased plasma volume, and decreased GFR so this stim increase of aldosterone secretion which will also promote edema
- pt is going to be hypovolemic
What proteins are lost in the urine?
- albumin
- clotting factors
- transferrin
- immunoglobulins (susc. to infection)
- Vit D binding protein: results in decreased levels of Vit D, this decreases calcium and then this will increase PTH
Cause of hypoalbinemia?
- partially due to loss of albumin through glomeruli
- also thought that albumin is catabolized in prox tubular cells of kidney
- low oncotic pressure stimulates hepatic lipoprotein synthesis leading to hyperlipidemia
Increase in lipids etiology? Risks?
- elevated levels of LDLs and TGs (HDL normal) due to increased hepatic synthesis and decreased peripheral metabolism
- this increases risk of CV disease
- lipiduria: OVAL FAT BODIES in the urine (fat in macrophages)
Occurrence of MCD?
- accounts for 90% of disease in children
- can occur in adults secondary to NSAIDs
- find only mild mesangial cell proliferation, no immune deposits and effacement (thinning) of epithelial cell foot processes
Etiologies of MCD?
- infections
- drugs: NSAIDs, lithium, ampicillin
- tumors: Hodgkins, leukemia
- allergies: food, bee stings, pollens
- other diseases: following allogenic stem cell for leukemia, following hematopoietic cell transplantation
Tx for MCD in children? SE of this med?
- respond well to steroids
- SEs: short term - insomnia, GI upset, HTN, psychosis, blood sugar increase
long term - immunosuppression, ulcers, cataracts, adrenal axis suppression
What is FSGS?
- most common lesion found in those with idiopathic nephrotic syndrome 35% of the time (Blacks - 50%)
- characterized by presence in SOME glomeruli of segmental areas of mesangial collapse and sclerosis - scarred tissue - have higher pressures going through rest of glomeruli
- can be primary and secondary forms
What are secondary causes of FSGS?
- HIV
- obesity
- lupus
- diabetes
- chemicals that harm kidneys
- meds
What is membranous nephropathy? How is it characterized?
- most common cause of nephrotic syndrome in adults
- characterized by:
basement membrane thickening with little infiltration, deposition of immune complexes on basement membrane - allow proteins to leak through - electron dense deposits along basement membrane
- primarily idiopathic may be due to autoabs
Secondary causes of membranous nephropathy?
- Hep B antigenemia and also Hep C
- autoimmune diseases such as lupus
- cancer
- drugs such as gold, captopril and NSAIDs
Complications of Nephrotic syndrome?
- edema
- hypovolemia
- HTN
- acute renal failure
- protein malnutrition
- thromboembolism
- infection: losing immunoglobulins
- deficiency of Vit D and hypocalcemia
- increased risk for development of atheroscerosis
Dx of nephrotic syndrome?
- 24 hr urine (excreting more than 3.5 g/24 hrs)
- renal bx: for definitive dx (GOLD STD)
- More studies that may be run - if thinking secondary cause:
ANA (autoimmune)
complement (C3)
serum or urine protein electrophresis (mult myeloma, IgGs)
Syphilis
Hep B and C serology’s
measurement of cryoglobulins
antistrep abs (cross over with PSGN)
What are the CIs to renal bx?
- uncorrectable bleeding diathesis
- small kidneys (indicate chronic irreversible disease)
- uncontrolled, severe HTN
- bilateral cystic kidneys or renal tumor
- hydronephrosis
- renal or peri-renal infection
- uncoop pt