Flashcards in Chronic Kidney Disease - Huch Deck (31)
What is the definition of chronic kidney disease?
best index of overall kidney function is glomerular filtration rate, typically estimated by measurement of creatinine clearance and by changes in serum creatinine concentration
What is the difference in urine analysis in chronic kidney disease when the disease is in the glomerulus vs the tubules?
in the glomerulus - has more protein
in the tubule - no heavy protein count, maybe pyuria
What are some factors that suggest chronic kidney disease>
most common asymptomatic until really bad
presence of peripheral neuropathy
bone changes consistent why hyperparthyroidism
waxy casts (cracks, sharp edges)
What are factors suggesting a tubular etiology of chronic kidney injury
absence of heavy proteinuria
inability to concentrate or dilute urine so that specific gravity is typically 1.010 isoosmotic to plasma
presence of hyperkalemia and metabolic acidosis out of proportino to the degree of renal insufficiency
What are factors that suggest glomerular etiology in chronic kidney disease?
presence of rbc casts
specific gravity great than 1.015
what is the most common cause of eosinophils in the urine
allergic interstitial nephritis
what are features of allergic interstitial nephritis?
eosinophils in urine
When initial injuring stimulus is removed in chronic kidney disease, describe the progress of the kidney function
chronic kidney disease will continue to worsen when the injuring stimulus is removed
What are common signs of advanced renal failure? commonly called uremia
early morning nausea
Uremia is 100% fatal unless?
reversible factors are identified which can improve GFR
renal replacement therapy is instituted
What are teh most common etiologies of advanced kidney disease in the US?
acute and chronic glomerular disease
polycystic kidney disease
what are disease dependent mechanisms of nephron injury
vascular, glomerular, tubular
what are disease independent mechanisms of nephron injury
glomerular hypertrophy (increase sngfr per nephron) - compensating for dying nephron
how does the kidney and nephrons respond to nephron loss?
compensatory glomerular hypertoprhy
compensatory glomerular hyperfiltration
a 50% decrease in renal mass results in only 20-30% reduction in GFr. Therefore, residual nephrons increased sngfr about 50%. t of f
What are effects of disease indpt processes like hypertrophy?
epithelial cell injury promoting proteinuria
hyaline accumulation in mesangial expansion leading to reduced capillary surface area for gfr
vascular capillary microaneurysms
endothelial cell injury
Greater than 50% loss of nephron mass results in increased risk of what?
proteinuria (focal segmental glomerulosclerosis)
particularly when present for more than 10 yrs
in cases of progressive nephron loss, why is protein restriction dangerous?
while it is tremendously helpful in reducing azotemia and reducing the workload of the glomeruli, it also leads to malnutrition
in proteinuria disease, what drugs have been shown to give extra advantage for bp regulation
acei and arbs
why would acei and arbs be particularly helpful in proteinuric diseases?
they stop the raas, which leads to efferent vasoconstriction, contributing to systemic htn, they lead to na retention, glomerular htn, and increased release of tgf-beta, promoting fibrosis
what are limitatinos of serum creatinine as a marker for gfr?
increased secretion occurs with decreased gfr, therefore, the serum creatinine will over-estimate true gfr
what are early changes in diabetic nephropathy?
hyperfiltration resulting in glomerular capillary hypertension and glom hypertrophy. have a gfr increase from 100 to 130
What are the clinical effects of diabetic nephropathy?
first abnormality is microalbuminuria that leads to overt proteinuria, reduced gfr and htn
what are histologic effects of diabetic nephropathy?
increased, mesagnial matrix, glomerular collapse and glomerulosclerosis
does inhibition of raas reduce plasma creatinine?
yes, because it tries to make sure the gfr is staying normal
What do most people die of before they ever get to dialysis?
do damaged nephrons function normally or abnormally?
normally, so loss of renal homeostasis is due to decreased number of nephrons.
what is the trade off hypothesis?
in order to maintain homeostasis despite reduced GFR, things happen to make sure homestasis occurs.
na balance htn
k hyperaldosteronism and htn
increased filtration by residual nephrons
why do you estimate gfr instead of using Scr?
because muscle mass determines cr, so there is no normal value for creatinine, only normal for the context
what is the equation for GFR estimation?
140-age/Scr X .85 (if fem)