Lab Abnormalities with Renal Disease Flashcards
what is the grading of AKI by the international renal interest society based on?
level of azotemia and urine output
what are the SDMA values for CKD by the international renal interest society?
<14: normal
14-18: equivacol
>18: likely renal disease
when does creatinine and BUN rapidly rise in terms of how much of the kidney is functioning?
when GFR is 20% of normal
there is more energy expended in the kidney on __________________ than on any other single entity
Na reabsorption
what does the proximal tubule transport system depend on?
Na transport
the sodium gradient drives entry of sodium at apical membrane, along with the cotransport of what things?
glucose
amino acids
phosphate
secretion of H, absorption of bicarbonate
what is the importance of Na reabsorption in the loop of henle?
creates medullaruy hypertonic gradient essential for concentrating urine
what happens in the distal tubule with Na?
pumped out of cell
filtrate to cytoplasm through Na/Cl cotransporter and Na channels: exchanged for K or H or cotransported with Cl
what does aldosterone do with Na channels?
increases Na channels in luminal membrane of distal tubular cells
what sodium levels do we see with acute kidney injury?
normal to increased by decreased GFR
which organic acids and bases is the proximal tubule important for excreting?
bile salts
oxalate
urate
catecholamines
what acid-base disturbance in common with renal disease?
metabolic acidosis
why is metabolic acidosis common with renal disease?
loss of ability to generate and secrete H
loss of ability to reabsorb bicarbonate
loss of ability to generate NH3 from glutamine
holds protons in filtrate (as NH4+)
loss of ability to secrete organic acids
what are the adverse effects of chronic metabolic acidosis?
lethargy
anorexia and vomiting
muscle wasting and weight loss
negative potassium balance
bone demineralization
what acid-base disturbance is common in cattle with renal disease?
metabolic alkalosis
how is K handled by the loop of henle?
works with Na to create concentration gradient
some K leaks back into lumen
what happens with K in the distal nephron?
can be secreted
negative luminal charge as Na moves into cell: K moves through channels into filtrate
is AKI usually associated with hyperkalemia or hypokalemia?
hyperkalemia
why is AKI usually associated with hyperkalemia?
decreased filtration, secretion, acidosis
most significant with oliguria or anuria
why is hyperkalemia exacerbated by acidosis?
K and H are exchanged in tissues
what is polyuric AKI and CKD associated with?
hypokalemia
why is polyuric AKI and CKD associated with hypokalemia?
diuresis increases K secretion
decreased intake
are cattle with kidney disease are more likely to be hypokalemic or hyperkalemic?
hypokalemic
why are cattle with kidney disease more likely to be hypokalemic?
anorexia
increased salivary excretion of K
impaired intestinal absorption of K
what serum potassium concentration is expected in a dog with a ruptured bladder?
high
what happens to most filtered calcium?
normally reabsorbed
what regulates active transport of calcium in the distal tubule?
parathyroid hormone
vitamin D
both increase Ca reabsorption
what happens to calcium with renal disease?
may stay normal, decrease, or increase
how does renal disease cause an increase in calcium?
uremia causes downregulation vitamin D receptor and calcium-sensing receptor
persistent, inappropriate increase in parathyroid hormone
who is hypocalcemia most often seen in?
small animals
horses with kidney disease are more likely to have __________________
hypercalcemia
where is phosphorous primarily reabsorbed?
proximal tubule
carnivores and omnivores excrete excess dietary phosphate, which requires _________________
normal GFR
what is fibroblast growth factor 23 produced by and in response to?
bone
rising phosphorous
what happens in small animals with decreased GFR and phosphorous?
hyperphosphatemia
meat eaters have excess phosphate: excrete
what is anemia seen with CKD like?
nonregenerative
decreased erythropoietin
shortened red blood cell lifespan
direct suppression of red blood cell production by uremic toxins
what is an important differentiating factor for CKD vs AKI?
lack of anemia in AKI
