T/F: oliguria and anuria are not required for a patient to have AIRF
What is the first detectable abnormality with AIRF?
poor urine concentrating ability
What findings in urine sediment are most typical of sever AIRF during early stages?
renal tubular epithelial casts (never normal to see these)
While not a true nephrotoxin, when do NSAIDs negatively effect the kidney?
NSAIDs impair kidney's ability to regulate blood flow --> can lead to damage if not properly hydrated/debilitated
T/F: dialysis, if started early, can make a difference in a patient with AIRF.
does ethylene glycol require short term or long term dialysis?
long term (months)
Nearly all ethylene glycol patients who present with ___ will die or be euthanized.
Will most lepto patients with azotemia die or survive? do they require short term or long term dialysis?
- usually only a few days of dialysis
is furosemide or amlodipine more helpful as treatment for lepto?
- amlodipine can increase survival
- (furosemide usually futile)
Are damaged kidneys from AIRF permanent or potentially reversible changes?
potentially reversible (unlike chronic renal failure)
what are some defining characteristics of AIRF?
- syndrome (many causes)
- abrupt decline in renal function
- recent onset (though not recognized) azotemia
- electrolyte/acid-base disturbances
- potentially reversible
What are the two main causes of AIRF?
nephrosis or nephritis
What is the #1 cause of nephritis in dog?
what are two main causes of nephrosis that causes AIRF?
ischemia and nephrotoxicity
what is typical cause of pre-renal azotemia? what is prognosis in most cases?
- if recognized and promptly treated, pre-renal azotemia readily resolves after restoration of renal perfusion
Is systemic arterial hypotension a requirement for ischemic nephrosis to occur?
not required but can be a factor
What antimicrobials are nephrotoxins?
- AMINOGLYCOSIDES (gentamicin)
What cancer therapeutic is nephrotoxic?
what mineral in the body is commonly associated with nephrotoxicity?
hypercalcemia (esp. w/malignancy like lymphoma)
what heavy metals are nephrotoxic? what plant is toxic to cats?
- arsenic and lead
- Easter lily
What part of the kidney is damaged with nephrotoxicity/ischemia? Is this better detected by light or electron microscope?
- tubules (direct binding to tubule membranes)
- electron microscope more sensitive
How does AIRF relate to GFR?
acute renal failure is associated with decreased filtration rate
how does hypotension affect GFR?
hypotension leads to vasoconstriction of afferent arteriole --> decreased GFR (as seen with large hemorrhage)
How does obstruction in the ureter affect GFR?
obstruction leads to back pressure --> increased hydrostatic pressure in glomerulus overwhelms vessel pressure --> decreased GFR
How does tubular back leak affect pathophysiology of AIRF?
damaged tubules leak filtrate
What does adrenergic (sympathetic) stimulation affect vessels in renal cortex?
how do prostaglandins effect vessels in renal cortex?
dilation to protect urine flow
what effect do NSAIDs have on prostaglandins?
NSAIDs inhibit PGE synthesis so kidney unable to dilate vessels --> worsens ischemia during hypovolemia/hypotension because unable to reverse constriction
Are Cox2 NSAIDs completely renal safe?
are nephrotoxins more damaging due to ischemia or direct cell injury?
- direct cell injury more damaging
- (add in ischemia = increased risk of injury)
what two qualities of the renal system worsens effect of nephrotoxin exposure?
- abundant blood supply so lots of exposure to tubular cells
- large tubular surface area for exposure/attachment
Do most patients die during induction, maintenance or recovery phase of AIRF? why?
- lasts 1-3 weeks so client can't afford hospital care or dialysis required (can't continue pouring fluids in oliguric pt)
Clinical signs are minimal/absent (often undetected) during which period of AIRF? Can removal of insult result in kidney return to normal function at this point?
- yes, kidney can return to normal
What is urine output like during maintenance phase?
variable (oliguria, normal, polyuria) depending on severity of insult
What is definition of maintenance phase?
sudden increase in serum creatinine that persists despite correction of pre-renal factors/rehydrate
Why does AIRF patient need a urinary catheter?
quantify urine output and it could be lepto (dog)
which phase signifies a critical amount of lethal tubular cell injury?