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Flashcards in NPNs Deck (32):
1

what is the kidney's function?

excrete undesirable end products of metabolism such as NPNs: urea (BUN), creatinine, uric acid, and also excrete organic acids and amino acids. It also maintains body homeostasis and has an endocrine function.

2

How does the kidney maintain body homeostasis?

electrolyte balance
acid base balance
water balance

3

What is the kidney's endocrine function?

primary: renin, erythopoeitin, and prostaglandins
secondary: produce vit d3

4

what are NPN compounds?

catabolism of proteins and nucleic acids result in the formation of so-called NPN compounds. Some of these metabolic products are derived from exogenous or endogenous proteins.

5

What does catabolism of proteins form?

urea

6

What does catabolism of purines form?

uric acid

7

What does catabolism of creatine and creatine phosphate form?

creatinine

8

What is Urea?

Blood urea nitrogen, >75% of NPN excreted in urine is urea

9

what is the greatest type of NPN that is excreted in urine?

urea, it accounts for more than 75%

10

Where is biosynthesis of urea carried out?

in the liver

11

Production of urea is dependent on several variables, what are they?

hight protein diet, hepatic function, increased protein catabolism (like muscle wasting--starvation), over hydration = urea excretion is increased, post renal obstruction. bacteria in urine causes decreased urea.

12

What is urea considered a measurement of?

renal function.

13

What are the expected values for urea?

plasma= 5-20, critical is over 100

14

What can cause increased BUN levels?

CHF, shock, hemorrhage, dehydration, renal impairment, renal failure, stones, tumors of bladder or prostate, severe infection, fever, stroke, major illness.

15

What causes decreased BUN levels?

low protein diet, malnutrition, newborn, severe hepatic insufficiency, severe vomiting or diarrhea, over hydration.

16

What are the normal ranges for BUN and what do they correlate with?

<8-10= overhydration
5-20= normal
20-26= dehydration
50-150 = implies impairment of GFR
150-250= extreme impairment

17

What is creatinine?

creatine is synthesized mainly in the liver and then transported in blood to other organs such as muscle and brain where it is phosphorylated to phosphocreatine, a high energy compound. A portion of creatine is muscle spontaneously and irreversibly converts to creatinine.

18

does the amount of creatinine vary greatly from day to day?

no, based on muscle mass

19

clinical application of creatinine: a test of renal function.

creatinine levels are a useful index of renal function, primarily GFR

20

What are CrCl tests used for?

to eval the GFR and to eval when administering nephrotoxic drugs.

21

As renal function decreases, what happens to GFR?

it decreases, and then the CrCl decreases.

22

What is normal GFR? what is end stage renal failure?

125-152, less than 5

23

What is Uric Acid?

it is the the major end product of purine nucleotide catabolism The conversion of purine nucleotides occurs in the liver.

24

What do plasma uric acid levels vary with?

dietary intake, renal disease, excess purine synthesis

25

In what clinical condition do we see increased uric acid?

gout, conditions involving increased cellular destruction, hyperuricemia, dehydration, hematologic conditions, chronic renal disease, chemotherapy, alcohol, lead poising, Lesch-Nyhan syndrome

26

what are some causes of decreased uric acid?

alcoholism with liver disease.

27

How is ammonia produced?

as amino acids are are deaminiated, ammonia is produced.

28

what could causes increased ammonia?

severe liver failure, chronic liver failure, reye's syndrome

29

expected findings: ACUTE RENAL DISEASE

increased: BUN, creatinine,
Decreased: CrCl
normal: uric acid

30

expected findings: chronic renal failure

increased: BUN, creatinine, uric acid
Decreased: CrCl

31

expected findings: gout

increased: uric acid
normal: BUN, creatinine, CrCl

32

expected findings: chemotherapy:

increased: uric acid
normal: BUN, creatinine, CrCl