Chronic Kidney Disease Flashcards
CKD is defined as
permanent reduction in GFR
Stage 1 CKD
Description
GFR
Action
Kidney damage, normal GFR
GFR > 90
Diagnose and treat
Stage 2 CKD
Description
GFR
Action
Kidney damage, mild decr GFR
GFR 60-89
Estimate progression
Stage 3 CKD
Description
GFR
Action
Moderate decr GFR
GFR 30-59
Treat complications
Stage 4 CKD
Description
GFR
Action
Severe decr GFR
GFR 15-29
Prepare for renal replacement
symptomatic
Stage 5 CKD
Description
GFR
Action
Kidney failure
Most common causes of CKD
1) diabetic nephropathy
2) hypertensive nephrosclerosis and renal vascular disease
3) glomerulonephritis
4) polycystic kidney disease
as serum creatinine, incr
exponential decline in creatinine clearance
Intact nephron hypothesis
nephrons still maintain glomerulotubular balance
filtration = net excretion
Magnification phenomenon
nephrons maintain external balance of solutes = magnify excretionof given solute
Individual solute control system
each solute has individual tubular handling and hormonol influences
trade off hypothesis
incr PTH in CKD to maintain serum calcium and incr renal phop excretion
With decr GFR, creatinine and urea ___
balance is maintained (rate of filtration) so the excretion rates are constant
With CKD, water
reabs decr
flow per nephron incr
–> hypoosmolarity
urine concentrating ability fixed around
with dehydration and low water intake
300 mOsm/kg
susceptible to dehydration
prone to water excess (hyponatremia) and water deficiency (hypernatremia)
why does nocturia occur in CKD
inability to concentrate urine at night
with CKD if you have incr sodium intake what happens
if you have incr extrarenal loss
edema
volume depletion
with CKD how does potassium regul change
decr tubular secretion of potassium
usu normal K+ with normal diet but incr K+ diet–> hyperkalemia
with CKD how does H+ regul change
nephrons produce more NH4+ to compensate for loss nephrons
until GFR too much retained H+ titrates down HCO3- –> non-anion gap metab acidosis
Uremia means
retaining substances in blood that are normally excreted
reasons for uremia syndrome
1) overproduction of PTH due to hypocalcemia and ANP
2) decr EPO production
3) decr 1-hydroxylation of vitamin D
why does anemia occur when GFR
1) EPO decr, lower end-organ response to EPO
2) blood loss, decr platelet function
3) decr RBC survival
why does HTN occur in mild CKD
1) too much retained Na and H2O
2) incr renin
3) incr symp tone
4) decr vasodilators
trade off hypothesis of mineral bone disease of CKD
1) kidney fails
2) phosphorous retained
3) decr Ca2+
4) stim PTH
5) excrete phosphorous
over time, decr GFR, incr PTH –> hyperphosphatemia and hypocalcemia and bone disease
