Test 2- Renal Flashcards
What hormones do the kidney produce?
EPO, Renin
Kidney actively involved w/ activating calcitriol (vit D3) and also w/ the RAAS (regulates blood pressure)-
What waste products are excreted by the kidney?
Urea, creatinine, NH4+, K+, H+, P04, water soluble drugs, hormones and enzyme s like PTH, and in
• dogs- amylase and lipase are inactivated/excreted by the kidney
What important substrates does the kidney conserve?
Na, Cl, HC03, Ca, Mg, glucose, amino acids, water.
o Also regulates acid base, regulates water balance
What percentage of nephrons cease to function after losing ability to
concentrate urine?
66% nephron loss! renal insufficiency
what percentage of nephron cease to function after noting azotemia
in the body?
• 75% of nephron impaired! as wella s producing
unconcentrated urine
remember: lose ability to concentrate first, then renal azotemia
occurs
what occurs w/ renal dz?
Retention of nitrogenous waste products (BUN, Creatinine), inability
to dilute/concentrate urine (isothenuric 1.008-1.012) and greater
than 75% nephrons are affected
What test can you run on serum; run on urine for urine function?
Serum- BUN, and creatinine concentration
• Urine- USG, Urine protein concentration, urine protein:cratinine
ratio, fractional excretion of protein, fractional excretion of
electrolytes
What is the cycle of Urea?
Liver takes amino acids, deaminates and creates urea. Urea is
moved into the blood and is measured by blood urea nitrogen. Urea gets filtered by the glomeruli and is excreted
! but the Bun concentration is dependent on the rate of production,
reabsorption and excretionBUN changes w/ rate of production, reabsorption and excretion
Liver production- increase protein in upper GI (high protein diet, upper Gi bleed. Increase the prodctuion of BUN increases serum BUN.
If you have liver failure, decrease production of BUN therefore decrease serum BUN.
Renal resbsorption depends on resorption rate of flow thru tubules. Slow flow rate (more BUN resorbed. Fast flow rate- decrease serum BUN.
What percent of BUN is excreted by the kidney/ reabsorbed by the kidney?
60% is excreted, 40% is reabsorbed
can urea be a measure of GFR in ruminants?
No! salivary and blood urea enter the rumen and the rumen microflora create amino acids from deaminiating the urea.
What is the cycle of creatinine?
Produced by endogenous muscle catabolosim- muscle creatinine
phosphate (energy stored molecule), constant rate of production is proportional to muscle mass. Muscle cells release creatinine into plasma and is filtered by the glomerulus and not reabsorbed (unlike urea) and therefore is an indicator of GFR
If creatinine is increased in the blood, what does it imply?
A decrease in GFR, and possibly altered kidney function (nephron
function)
What is Urine specific gravity?
An estimate of urinary concentrating capacity
. Assess in conjunction
w/ serum BUN and creatinine. ! look at the USG along w/ BUN and
Creatinine! collect blood and urine at same time.
When would it be appropriate to obtain a sample and measure USG?
When suspected of renal dz, geriatric wellness, history of PU/PD
What is necessary by the kidney to create a concentrated urine?
At least 33% functional nephrons, production and responsiveness to ADH, and have the ability to create a concentration gradient (medullary hypetonicity, production of urea, and production of aldosterone)
What is necessary by the kidney to produce a dilute urine?
Ability to actively resorb sodium and chloride form ascending
limb of the loop of henle, and little to no water removed by the
colleting duct
What are the USG ranges by species?
Dog- 1.001- 1.060; cats 1.001-1.080; horse/bovine 1.001-1.055.
•  IF THE USG IS NOT REPRODUCIBLE, IT IS NOT
o If isothenurinic the kidney is incapable of altering the amount of water leaving the body.
o If hyposthenuric it is an active process and producing a dilute urine
o If USG is > than 1.017! some concentrating ability.
What are the minimum concentrating capacities for USG per species in a dehydrated state?
Dog 1.030; cat 1.035; horse/cattle 1.025 if you get these numbers you know the kidney is able to concentrate urine. If not something wrong
o The cause of increase BUN, and Increase Creatinine is prerenal when urine specific gravity is increased w/ these values due to dehydration
what is specific of urine protein concentration in dogs?
Healthy dogs may have a measureable protein concentration
.Remember small proteins pass through the glomerulus- most
are reabsorbed by the proximal renal tubules (usually not detected in urine in most species)
How can urine protein concentration be measured?
w/ a regent strip- changes color w/ associated [protein] in urine. ! negative, trace, +, ++, +++,++++
o often UTI, pyelonephritis, urolith can cause some irritation in tissue to cause bleeding and see protein and inflammation in urine
what causes polyuria?
Inability to concentrate urine causes polyuria – implies that you
have a loss of 66% of functional renal mass w/ isothenuric urine
(low USG)
What are your DDX for polyuria?
Renal- renal failure, and pyelonephritis are your renal causes
• Extrarenal- diuresis, medullary washout, diabetes,
hyperadrenocritcism, pyometra
What is azotemia?-
75% renal function lossRetention of nitrogenous waste product in blood: increase [BUN] and/or increase [CREA]. Pre renal (blood, liver, GI), renal; post renal (ureter, bladder, urethra)