Cross Species - Chemistry, Kidneys & Pancreas

Question 1

what components from lab work should always be assessed together when interpreting kidney function?

Answer 1

BUN, creatinine, urinalysis with USG!!!

Question 2

what do BUN & creatinine represent?

Answer 2

glomerular filtration rate

Question 3

a decrease in GRF causes an increase in what lab values on a chemistry panel?

Answer 3

increased BUN & creatinine = azotemia

Question 4

what are the 3 different types that an azotemia could be?

Answer 4

pre-renal (dehydration), renal (kidney disease), & post-renal (urinary tract obstruction)

Question 5

what is uremia?

Answer 5

clinical presentation of azotemia - vomiting, anorexia, & weight loss

Question 6

why is a USG so important when looking at an azotemic patient?

Answer 6

it is used to identify the type of azotemia that is present - pre-renal is usually increased, renal azotemia is isothenuria 1.008-1.012

Question 7

what is BUN?

Answer 7

byproduct of catabolism of digested proteins that are synthesized from ammonia in the hepatocytes into urea

Question 8

urea & NaCl maintain what in the kidneys?

Answer 8

renal medullary concentration gradient which contributes to urine concentration

Question 9

how is BUN excreted? what about in ruminants?

Answer 9

urine, saliva, sweat, high amounts in colon in horses, up to 60% can be reabsorbed based on renal blood flow - in ruminants, it is excreted into the GIT & used for protein synthesis

Question 10

if there is no concurrent increase in creatinine, what is the most common cause of an increased BUN?

Answer 10

upper gi bleed!!! or high protein meal

Question 11

apart from a GI bleed, what other causes result in an increased BUN?

Answer 11

azotemia (pre, renal, or post) - early azotemia may see BUN elevation with normal creatinine otherwise creatinine will be increased

Question 12

what are the top causes of a decreased BUN?

Answer 12

hepatic dysfunction (portovascular anomaly), dietary protein restriction, & polyuria (diabetes mellitus)

Question 13

what is creatinine? how is it excreted? why is this important?

Answer 13

breakdown product from normal muscle catabolism that has normal production & excretion in equilibrium - excreted by the kidney, freely filtered, & not reabsorbed, so most reliable indicator of GFR

Question 14

why are small elevations in creatinine significant?

Answer 14

increases greater than 0.2 mg/dL in 48 hours is suggestive of acute kidney injury!!!

Question 15

what is the top cause of increased creatinine?

Answer 15

decreased GFR - 75% reduction in renal mass before an increase is seen!!!

Question 16

what is the most sensitive lab marker for horses & ruminants for decreased GFR?

Answer 16

creatinine

Question 17

why can horses have a slightly higher normal creatinine value? what about foals?

Answer 17

heavily muscled!! foals with placental insufficiency may have increased creatinine but it should decrease by 50% every 24 hours

Question 18

what is the top cause of decreased creatinine?

Answer 18

decreased muscle mass particularly in small animals with muscle wasting secondary to chronic kidney disease - creatinine can underestimate renal disease severity

Question 19

apart from creatinine, what are some other markers of GFR that can be measured?

Answer 19

SDMA in IDEXX labs - inulin clearance, but that has fallen out of favor

Question 20

T/F: amylase & lipase are poor, non-specific indicators of pancreatic injury in small animals & isn’t validated in large animals

Answer 20

TRUE

Question 21

what is the most sensitive & specific marker for pancreatic injury indicators?

Answer 21

pancreatic lipase immunoreactivity

Question 22

when are cPLI/fPLI tests used?

Answer 22

used to assess for pancreatic inflammation for acute or chronic pancreatitis

Question 23

what does trypsin like immunoreactivity evaluate? what is it the diagnostic of choice for?

Answer 23

evaluates pancreatic function but NOT inflammation - test of choice for diagnosing EPI