Renal System- Schoenwald Flashcards
The main function of the nephron is to _______ blood and so larger substances like protein and rbc usually do not pass and it is BAD if they do
filtration
Proximal tubule ________ large quantities of H20 along with glucose, uric acid, Na, Cl and HCO3
reabsorbs
Loop of Henle further ________ Na,Cl and H20
reabsorbs
Distal tubule controls _______ of Na, K, HC03 and H into collecting duct
excretion
Collecting duct ______ amount of water in urine due to effect of Antidiuretic hormone (ADH)
regulates
Name the three renal function tests?
- BUN
- Cr
- Urinalysis
This test measures the concentration of nitrogen (urea) in serum and is a marker of protein metabolism
BUN
This is a product of skeletal muscle contraction and daily production depends on muscle mass. It is entirely excreted by the kidneys/directly related to renal function
Creatinine
Elevations in Cr suggest what?
Chronicity of renal disease
If you double your Cr, what does this mean?
50% decrease in renal fxn
Which two groups have decreased lower Cr assuming no renal disease?
females, cachetic patients, spinal cord injury
*not kids
This is the test most accurately used to assess GFR, however, creatinine clearance is generally the test ordered
inulin filtration rate
What is the female, normal and male Cr clearance ranges?
Female- 90 to 107
Normal 90 to 140
Male 107 to 140
An increase in Cr = a ______ in GFR
An increase in Cr = a decrease in GFR
This is useful for assessing kidney function in acute or chronic renal failure, monitoring effects of drug therapy and monitoring therapeutic drugs and determining dosage
Creatinine clearance
To determine a CrCl, you need what test?
A 24 hr urine
-Serum Cr drawn within 24 hours of urine collection
What is the equation for CrCl?
(urine creat x urine volume)/plasma creat
This calculation is based on serum creat and is quick and doesnt need 24 hr urine collection?
Estimated GFR
This eqn is used to calculate renal dosing and is nice because you don’t have to use 24 hour urine studies?
Cockroft Gault eqn
What factors are needed for the Cockcroft-Gault equation?
- Age
- Weight
- Serum Cr
- M/F
What is the Cockcroft-Gault equation?
CrCl = (140-age) x weight/(Cr x 72)
**must multiply by 0.85 if FEMALE to correct for muscle mass
In the Cockcroft-Gault equation you must do something for a female, what is it and why do you have to do it?
Multiply X 0.85 if women to correct for mm mass
MDRD eqn stands for: Modification of Diet in Renal Disease and it takes into account these factors:
- age
- sex
- ethnicity
*not used as much because only takes into account white & black and no other ethnicities
What is the MDRD eqn?
GFR mls/min = 1.86 x PCr x age
In the MDRD eqn, you must multiply by ______ for a female and _________ if african american
- Multiply x .742 if female
- Multiply x 1.210 if African American
Can you explain why with a decrease in GFR there is an increase in Cr?
Lower the GFR = lower the filtration rate so all the Cr can’t be filtered into the urine and it is being built up in the blood serum instead
If a urine dipstick is -, what should you do?
Microscopic analysis
Acidic urine deters _______ _____
bacterial growth
*less likely there is a UTI
What is a normal specific gravity?
1.010-1.025
What does a high specific gravity mean?
concentrated urine- dehydrated
What does a low specific gravity mean?
dilute, hydrated OR renal failure because kidneys are not working to filter out
_______ is a main contributor to specific gravity
Na (sodium)
Ketones measure a high _______ diet
protein
This is positive in excessive vomiting and dehydration
ketones
What is the threshold for glucose spillage into the urine?
> 300
Protein in urine + edema= ?
Nephrotic syndrome
If glomerular membrane is injured, protein is ________
elevated
These two labs are elevated in liver damage?
Bilirubin and urobolinogen (obstruction of bile duct)
What can cause a false positive blood urine microscopy?
myoglobin
What can cause a false negative blood urine microscopy?
Vitamin C
Painless hematuria + smoking should make you think of what?
Bladder cancer
If RBCs are + on UA, likely _______ will also be positive
protein
What test detects WBCs in urine?
Leukocyte esterase
Leukocyte esterase is pos or neg in UTIs?
positive
T/F: Leukocyte esterase and nitrate is a color based test so dark urine can give false +
true
Gram - organisms produce ________ which converts nitrate to nitrite
reductase
This test is also + in UTIs
nitrite
If you see WBC on microscopic UA, think…
sterile pyuria think TB
If you see RBC on microscopic UA, think…
infection, renal calculi
If you see eosins on microscopic UA, think…
interstitial nephritis
Casts form in what part of the nephron?
distal and collecting tubules- max concentration
Hyaline casts think…
normal after exercise, can be present with chronic renal failure
Red cell casts think…
glomerulonephritis, SBE
White cell casts think…
pyelonephritis
epithelial “muddy brown” casts think…
tubular necrosis
granular casts think…
nephrotic syndrome, lead toxicity, glomerulonephritis
waxy casts think…
renal failure-acute tubular necrosis
Crystals can be found in normal urine but can also be marker for _____
stones
calcium oxylate crystals
kidney stones