Flashcards in Proteinuria Deck (21):
Why can creatinine be used to estimate GFR?
Creatinine is produced on a constant basis by metabolism of muscle creatine. It is freely filtered by the glomeruli, and minimally secreted by the tubules.
Why do normal serum creatinine values differ between men and women?
men have more muscle so there is more breakdown resulting in higher normal levels of creatinine
What are normal creatinine values?
In men 0.9 to 1.3 mg/dl or 79 to 114 micromol/L
In women 0.8 to 1 mg/dl or 70 to 88 micromol/L
In children 0.5 to 1 mg/dl or 0.44 to 88 micromol/L
What happens to creatinine values in children as they grow?
The values gradually increase as the child gains more body mass therefore muscle mass
Decreasing GFR by half decreases urine output by half and what happens to serum creatinine?
Besides creatinine, what can also be used to measure GFR?
What is a normal GFR?
What are the GFR differences for the stages of chronic kidney disease?
stage I >90 (ml/min) >stage II >60> stage III >30> stage IV >15> stage V
What is the relationship between GFR and serum creatinine?
Why do GFR calculations have such wide ranges of normal?
24 hour urine collections are difficult.
Blacks, men and younger adults make more creatinine than do women and older people.
Formulas try to correct for these, but not sure what is most accurate.
Can we use formulas for sudden changes in kidney function?
Cannot use the formulas or rely on the absolute level of serum creatinine
What is a urine dipstick?
dry chemistry perfected to react with certain substances if they are present in the urine. fairly trustworthy.
How do we quantify urine protein?
can normalize the excretion of any substance in the urine to creatinine.
stop urine testing does not correspond as well as 24 hour urine collection but still works.
What happens to protein in normal kidneys?
some plasma protein is filtered, several grams/day and then there is Tubular re-absorbtion, also several grams/day = balanced
What happens to protein in diseased kidneys?
glomerular disease leads to protein leak that overwhelms tubular reabsorption causing loss of albumin, low plasma oncotic pressure leading to edema.
In health, how much is the maximum urine protein?
maximum of 150 mg/day of which most are tubular proteins
How much protein per day may cause nephrotic syndrome?
Urine protein more than 3 grams per day
What is micro-albuminuria?
30 to 300 mg albumin per 24 hours or 20 to 200 microgram per minute
Is albumin in the urine normal?
Do urine dipsticks detect micro-albuminuria?