aki Flashcards
describe aki
abrupt, acute, decline in kidney function.
acute - hours/days
OFFICIALLY
how much the creatinine has incr from
increased from it’s normal (baseline) level over a set period of time, OR
How much the urine volume has decreased over a set period of time
what is the criteria for the severity of aki?
3 stages, with stage 3 being the most severe stage of AKI.
Criteria of severity is based on Serum Creatinine or Urine Output
3 classifications of aki?
There are 3 main classifications of AKI, and these depend on where in the kidney the injury has taken place.
Pre-renal is the most common type and could be due to reduced blood flow to the kidney, therefore there is decreased perfusion. Could be due to reduced blood pressure, low blood volume, dehydration, GI bleed.
Post renal is the rarest type, that occurs in 5 – 10% of patients, and this is due to obstruction to outflow from the kidneys, for example prostate cancer or BPH. So kidneys function fine, but urine can’t flow out due to a blockage.
Intrinsic relates to actual damage to the functional tissues of the kidneys itself, which could be due to acute interstitial nephritis, which is hypersensitivity reactions that may be drug induced, rhabdomyolysis or medications.
risk factors of aki?
Aged 65 or over
Dehydration
CKD (AKI on CKD)
History of urological obstructions
Chronic conditions: Heart failure, liver disease, diabetes
Sepsis / severe infections
Medications / Dyes
(NSAIDs, ACE inhibitors, Diuretics, Aminoglycosides)
Iodine-based contrast agents
Why is it important to check blood creatinine levels?
Good indicator of kidney injury. The higher the Creatinine, the worse the kidney function
Kidneys maintain blood creatinine at a specific levels
If creatinine levels in the blood are rising it could indicated that the kidneys are not functioning to their full ability to clear the creatinine
Measurement of creatinine concentration is used to:
Determine sufficiency of kidney function
Determine severity of kidney damage
Monitor progression of kidney disease
What is pre-renal AKI?
Reduced blood flow to the kidney
What causes pre-renal AKI?
Reduced BP
Hypovalaemia (decreased blood volume)
Dehydration
GI bleed
Sepsis
Cardiac & liver failure
Burns
Medications
What is post-renal AKI?
Obstruction to outflow from the kidneys
What causes post-renal AKI?
Benign prostatic hypertrophy (BPH)
Prostate cancer
Renal calculi
Retroperitoneal fibrosis
Medications
What is intrinsic AKI?
Damage to the functional tissues of the kidney
What causes intrinsic AKI?
Acute interstitial nephritis
Myeloma
Rhabdomyolysis
Immunological renal disease
e.g. vasculitis/ medications
What is the most common classification of AKI?
pre-renal
Why is it important to check blood creatinine levels?
If rising, could indicate kidneys are not functioning correctly
Determine sufficiency of kidney function
Determine severity of kidney damage
Monitor progression of kidney disease
How can GFR be calculated?
(1) eGFR (mL/min/1.73m^2)
2) Creatinine clearance (mL/min
What are disadvantages of using eGFR to estimate GFR?
Does not account for a patient’s bodyweight
Can dramatically underestimate the creatinine clearance in renal failure
Not interchangeable between labs
