19 - Glomerular Disease 1 Flashcards
normal protein excretion via kidneys / day
<20 mg/d
cutoffs betweeen microalbuminuria, subnephrotic proteinuria, and nephrotic proteinuria
microalbuminuria is 30-300 mg/d
subnephrotic is 300-3000 mg/d
nephrotic is >3.5 g/d
general pathogenesis/mechanism of nephrotic syndromes
leak of protein through glomerulus due to disruption of slit diaphragm
can be a podocyte injury or a specific defect in slit diaphragm (nephrin mutation, eg)
definition of nephrotic syndrome
proteinuria (>3.5 g/d) hypoalbuminemia (<3 g/dL) edema hyperlipidemia lipiduria
how does nephrotic syndrome cause hyperlipidemia?
inc lipoprotein synth by liver due to dec in plasma oncotic pressure
lipiduria appearance in urinalysis buzzword
maltese cross
having nephrotic syndrome puts you at inc risk for these 4 conditions/problems
CAD/atherosclerosis (2/2 hyperlipidemia)
infections (urinary loss of IgG and complement)
thrombosis (inc synth of coag factors by liver and urinary loss of anti thrombin 3)
poor growth (kids) / osteomalacia (loss of vit D)
frequent causes of nephrotic syndrome (7)
diabetic nephropathy minimal change dz amyloidosis membranous nephropathy focal segmental glomerulosclerosis lupus nephritis membranoproliferative glomerulonephritis
general pathogenesis of nephritic syndrome
active inflammation/injury in glomerulus > damage/loss of capillary surface area > loss of filtration and blood flow to kidney
mesangial cell prolif, endothelial cell prolif and injury, podocyte injury
definition of nephritic syndrome
non-nephrotic range proteinuria (btwn 500 and 3500 mg/d)
reduced GFR
active urine sediment (RBCs, WBCs, casts)
edema
HTN
mechanism for edema in nephrotic vs nephritic syndrome
nephrotic - loss of albumin - dec oncotic pressure of serum
nephritic - Na and water retention due to dec GFR
rapidly progressive glomerulonephritis (crescentic GN)
severe glomerular injury > presence of crescents of proliferative cells and sometimes fibrin in bowman’s space
rapid deterioration of renal fn (days to wks)
frequent causes of nephritic syndrome (5)
postinfectious GN membranoproliferative GN IgA nephropathy crescentic GN lupus nephritis
in situ vs circulating immune complex deposition in glomerular disease
in situ - antigen is in kidney, complexes form attached to the kidney
circulating - complexes have formed elsewhere in the body and circulate in blood but get stuck in the kidney
ex of in situ immune complex deposition glomerular diseases (2)
goodpasture disease (glomerular BM) membranous GN (phospholipase A2 receptor)
