acute kidney injury 2 Flashcards
what type of test is often done to see if there is kidney blockage, or a structural issue with the kidney?
renal imaging (ultrasonogram)
what are two types of prerenal hypoperfusion?
- systemic hypoperfusion
2. isolated renal hypoperfusion
what indicates isolated renal hypoperfusion
bilateral renal artery stenosis embuli
cholesterol or thrombotic
what indicates systemic hypoperfusionq
- intravascular volume depletion
2. relative decrease in volume
what are 3 things that indicate intravascular volume depletion by systemic hypoperfusion
- dehydration
- hemorrhage
- overdiuresis
what are 3 things that indicate relative decrease in volume due to systemic hypoperfusion
- heart failure
- liver disease
- nephrotic syndrome
what is nonoliguric disease typically classified as prerenal decreases GFR and usually stops when agent causing it is removed?
functional acute renal failure
what do ACE inhibitors inhibit?
what does this cause?
where?
angiotensin II
what general change causes functional acute renal failure?
hemodynamic changes ( no direct kidney pressure)
what two endogenous compounds are the main factors for vasodilation and vasoconstriction
- prostaglandins
2. angiotensin II
what compound effects the afferent arteriole’s constriction and dilation?
prostaglandins
what compound effects the efferent arteriole’s constriction and dilation?
angiotensin II
what are the 3 main causes of functional acute renal failure
- NSAIDs
- ACEI’s and ARB’s
- Calcineurin inhibitors (immunosuppresents, ie cyclosporine)
what is the MOA of ACEI/ARB induced AKI?
vasodilation of efferent arteriole (leaving kidney)
angiotensin II causes what?
vasoconstriction
what can commonly be seen lab values that appears significant at the start of an ACEI?
rise in SCr of less than 30%
why should ACE inhibitors be started at low doses and slowly increased
due to vasodilation increasing SCr
what are 4 conditions that can exacerbate change in renal function with ARBs and ACEI’s?
- dehydration
- renal artery stenosis
- CHF
- Cirrhosis
(still can use with these pt’s just monitor closely)
what accounts for around 37% of drug induced AKI
NSAID’s
what enzyme is essential for maintaining renal hemodyanamics, effected by NSAIDs
COX-2
NSAID’s cause what problem, where leading to AKI?
constriction of afferent arteriole, leading to hypoperfusion
what are two common calcineurin inhibitors
tacrlimus
cyclosporine
what are calcineurin inhibitors often used for?
how long are pt’s at risk of CKD after this
post transplant immunosuppressant’s
5 years after transplant of nonrenal organ
what is the dose limiting adverse effect of tacrolimus and cyclosporine (calcineurin inhibitors)?
nephrotoxicity
when does nephrotoxicity normally present with cyclosporine therapy
within 6 months of cyclosporine therapy
what MOA do calcineurin inhibitors have to cause ARF
reversible, but extreme vasoconstritction and injury to afferent arteriole
what are 2 causes of functional ARF other than drug induced
- hypercalcemia - direct vasoconstriction
2. hepatorenal syndrome - ARF in pt’s with severe liver disease (probably mediated by prostaglandins)
when prerenal or functional ARF are seen what should be thought of immediately as cause?
what should be the next step in diagnosis
hypoperfusion
is it systemic hypoperfusion or renal hypoperfusion
