Intro to Renal Function Flashcards
Low protein diet effects on BUN ….
lowers BUN
BUN
blood urea nitrogen
Upper GI bleed …
increases BUN
Hypotension w/ low renal perfusion …
high BUN
High dose corticosteriod …
increases BUN
(induces a catabolic state which breaks down protein into urea )
Tetracycline antibiotics
high BUN
induces a catabolic state
What is creatinine dependent on?
body mass
OCT
secretes creatinine into tubulues
How is creatinine formed?
formed from creatine
this is an anabolic process
Anabolic steroids effect on Cr
high Cr
LE amputation effect on Cr
lower Cr (less muscle mass)
OCT inhibitor
High Cr
(cannot secrete creatinine into tubule)
Creatine supplements lead to …
transient increases in creatinine
What is the best measure of kidney function?
GFR
When can you calculate GFR?
only when creatinine is in a steady state
do NOT calculate if creatinine has changed over past couple days
What is the preferred formula for GFR?
2021 CKD-EPI formula
What is the preferred formula for GFR in children?
Schwartz formula
How can creatinine be misleading?
could look normal but is actually high if they have low muscle mass
What can you use to estimate GFR if you cannot use creatinine?
cystatin C (best option)
24 hr creatinine clearance (hard to measure)
What findings indicate glomerular damage?
RBC casts and proteinuria
What are the 2 types of glomerular damage?
nephritic or nephrotic
Nephritic syndrome
HTN and proteinuria (but lower than in nephrotic syndrome)
Nephrotic syndrome
high proteinuria, more edema and hypoalbuminemia
Why does nephrotic syndrome cause hypoalbuminemia?
nephrotic syndrome has high proteinuria
albumin is the most abundant protein in urine
so, having lots of proteinuria leads to low serum albumin levels
Glomerular proteinuria
mainly albumin
impairment of glomerular basement membrane
Tubular proteinuria
impaired reabsorption of proteins
seen in heavy metal poisioning
see low weight proteins in urine
Overflow proteinuria
mass excretion of low weight proteins
hemoglobinuria, myoglobinuria, etc.
Post-renal proteinuria
problems below the kidney like inflammation, bleeding and malignancy
