Acute Kidney Injury

Question 1

AKI Epidemiology

Answer 1

30% of ICU admissions

Question 2

Define Acute Renal Failure/AKI

Answer 2

Sudden impairment of kidney function resulting int he retention of nitrogenous and other waste products normally cleared by the kidneys
Increased BUN and SCr

Question 3

Define Anuria

Answer 3

No urine production

Question 4

Define Oliguria

Answer 4

Decreased production of urine

Question 5

BUN

Answer 5

End product of protein catabolism

Produced from ammonia converted to urea and excreted

Question 6

Increased BUN =

Answer 6

Increased protein catabolisms

Question 7

No BUN =

Answer 7

Liver failure or dysfunction

Question 8

Creatinine

Answer 8

End metabolite from our muscles

Proportional or associated to the amount of muscles in the body

Question 9

Pre-renal AKI

Answer 9

Outside the kidneys
Leads to decreased blood supply of the kidneys
Associated with decreased amounts of blood

Question 10

Post-renal AKI

Answer 10

Blockage of the urine outflow

Question 11

Pre-renal + BUN

Answer 11

Reabsorbed

Question 12

Pre-renal + GFR

Answer 12

Decreased GF bc decreased BF

Lower amount of filtrate

Question 13

Lower amount of filtrate =

Answer 13

Increased reabsorption bc slower flow of filtrate

–> increased BUN

Question 14

Creatinine reabsorption

Answer 14

NOT reabsorbed!!

Decreased GFR = increased creatinine bc of decreased excretion not reabsorption

Question 15

Renal AKI

Answer 15

GFR decreased
Disease is effecting kidney parenchyma (nephron malfunction)
REDUCED FILTRATION AND REABSORPTION
Increased BUN (not as much as pre-renal) and creatinine (not bc of reabsorption)

Question 16

BUN:creatinine Maintain vs Increased

Answer 16

M: problem with the kidney itself
I: Pre-renal kidney failure

Question 17

Pre-renal =

Answer 17

Hypovolemia
Decreased CO (ischemic heart disease or MI)
Decreased effective circulating volume (CHF and liver failure)
Impaired renal autoregulation (NSAIDs, ACEI/ARBs, cyclosporine)

Question 18

Intrinsic/Renal =

Answer 18

Acute glomerulonephritits
Ischemia
Sepsis/infection
Vasculitis 
Maliginant hypertension
Nephrotoxins

Question 19

Nephrotoxins are

Answer 19

Iodinated contrast
AG
Cisplatin
Amp B
Rhabdomyolysis
Myeloma
Crystals

Question 20

Post-renal =

Answer 20

Bladder obstruction

Question 21

Pre-renal Azotemia

Answer 21

Most common form of AKI
Inadequate renal plasma flow and intraglomerular hydrostic pressure
No parenchymal damage to kidney

Question 22

Autoregulation

Answer 22

Pressure that is inside the capillary can be controlled in a certain range
Independent of fluctuations of BP
Important to maintain constant GFR

Question 23

Drop in BP bc of NSAID + Autoregulation

Answer 23

Decreased PGs

Increased Ang II

Question 24

Drop in BP bc of ACEi/ARB + autoregulation

Answer 24

Increase PGs

Decreased Ang II

Question 25

Autoregulation of GFR is adversely affected by:

Answer 25

``` Atherosclerosis HTN Increased age NSAIDs ACEI/AT1 blockers ```

Question 26

Pre-renal Hepatorenal Syndrome

Answer 26

Systemic vascular resistance is markedly redued due to primary aterial vasodilation in the splanchnic circulation --> activation of vasoconstrictor response Blood is trapped in splanchnic circulation so there is not enough blood for the kidney so it thinks is hypovolemic

Question 27

Sepsis

Answer 27

Can affect function of the endothelial cells (bacteria + inflammatory cytokines = bad for cells) Interstitial and tubules are affected as well

Question 28

Ischemia leads to

Answer 28

Microvascular injury and tubular injury due to lack of oxygen cells die and cause inflammation --> kidney injury

Question 29

Surgery could leads to

Answer 29

Severe hemorrhage and loss of blood volume which can lead to hypoperfusion of the kidney --> injury

Question 30

Nephrotoxins are

Answer 30

``` Contrast agents Abx (AG) Chemo agents Environmental toxins Myoglobin, hgb, urate, meyloma light chains ```

Question 31

Post-renal AKI resembles:

Answer 31

Pre-renal but last longer and will have a clinical picture of renal + kidney damage Anything that blocks the UT

Question 32

Post-renal considerations

Answer 32

Bilateral vs unilateral | Time

Question 33

Blockages caused by

Answer 33

Kidney stones Prostatic enlargement Cancer/tumors Infections

Question 34

Diagnosis of AKI

Answer 34

SCr rise of 0.3 mg/dL or 50% higher than baseline within a 24-48 period OR reduction of urine output to 0.5 mL/kg for greater than 6 hours Ultrasound or CT for postrenal AKI Kidney biopsy Biomarkers: KIM-1 or NGAL

Question 35

Urine findings in AKI

Answer 35

``` Anuria is rare Oliguria is less than 400mL/24 hours Red/brown urine Mild proteinuria Hyaline casts ```

Question 36

AKI complications

Answer 36

``` Volume status BP Electrolytes Acid and base Excretion of waste products Uremia Hypervolemia (Na and water retension, PE) Recovery: Hypovolemia, polyuria, and osmotic diuresis Hyperkalemia (arrhythmias) ```

Question 37

Common principles of AKI management

Answer 37

Optimization of hemodynamics Correction of fluid and electrolyte Discontinuation of nephrotoxic medications Dose adjustments for meds