acute kidney injury

Question 1

AKI definition

Answer 1

a sudden decline in renal function over hours to days

Question 2

non-oliguric

Answer 2

urine output is >400c/day

Question 3

oliguric

Answer 3

urine output is <400 cc/day

Question 4

anuric

Answer 4

urine output is <100cc/day

Question 5

which group tends to have the highest rate of AKI

Answer 5

pts in the ICU, 50% have AKI

Question 6

what does RIFLE stand for

Answer 6

risk, injury, failure, loss, end-stage kidney disease

Question 7

what is RIFLE?

Answer 7

a classification system for AKI based on GFR and urine output

Question 8

what is AKIN?

Answer 8

AKI network

classification for AKI based on Scr and urine output

Question 9

What is KDIGO used for?

Answer 9

it is a staging system that is based on Scr and urine output

stages correlate with the risk of death and long-term outcomes

Question 10

AKI stage 1 KDIGO

Answer 10

increase in SCr > 0.3 in 48 hrs OR
increase in SCr >1.5x baseline OR
urine volume < 0.5 ml/kg/hr x 6 hrs

Question 11

3 main types of AKI

Answer 11

pre-renal
post renal
intrinsic renal

Question 12

pre-renal AKI

Answer 12

any condition that leads to decreased renal perfusion

60% of cases of AKI

Question 13

pre-renal AKI pathophys

Answer 13

decreased perfusion activates RAAS.

release of renin then releases ADH= vessel contraction to preserve blood flow to heart and brain

=decreased GFR so kidneys respond by concentrating urine and holding onto Na to try and reabsorb water

Question 14

causes of pre-renal AKI

Answer 14

decreased volume (GI losses, hypovolemia)
decreased effective volume (cirrhosis, CHF)
Rx (ACE/ARBs, NSAIDs)

Question 15

cardiorenal syndrome

Answer 15

cause of pre-renal AKI that results from decreased cardiac performance leading to decreased cardiac output which leads to decreased renal perfusion and increased water and Na retention (hypervolemia)

Question 16

hepatorenal syndrome

Answer 16

consequence of cirrhosis that causes pre-renal AKI due to decreased renal blood flow

most likely due to portal hypertension leading to decreased GFR

Question 17

clinical presentation of pre-renal AKI

Answer 17

signs of volume depletion
orthostatic hypotension
reduced skin turgor, dry mucous membranes
ascites, edema
(history is essential for revealing cause)

Question 18

pre-renal AKI diagnostic findings

Answer 18

FeNA <1%
BUN:Cr ratio > 20:1
urine Na <20

Question 19

how do you determine the mechanism of AKI?

Answer 19

clinical presentation, history, response to therapy

Question 20

pre-renal AKI treatment

Answer 20

supportive care
fluid repletion with normal saline or LR
treat underlying cause (blood transfusions, hold rx that can contribute)

Question 21

you would give ____ for hypovolemia and ___ for hypervolemia

Answer 21

IV fluids

diuretics

Question 22

what is FeNA?

Answer 22

fractional excretion of Na, used to distinguish pre-renal AKI from ATN
FeNA<1= pre-renal AKI
FeNA > 2= acute tubular necrosis

*may not be accurate

Question 23

pre-renal AKI response to treatment

Answer 23

rapid improvement in renal function following acute intervention

Question 24

intrinsic AKI

Answer 24

AKI that leads to severe direct kidney damage

~35% of cases of AKI

Question 25

types of intrinsic renal injury

Answer 25

tubular interstitial glomerular vascular

Question 26

acute tubular injury

Answer 26

causes 85% of intrinsic AKIs | can be ischemic or nephrotoxic (from drugs)

Question 27

ischemic ATI pathophys

Answer 27

severe decrease in renal blood flow leads to tubular cell injury and inflammation secondarily, which ultimately results in necrosis of cells and impaired reabsorption

Question 28

toxic ATI pathophys

Answer 28

injury occurs to tubular cells directly due to nephrotoxic substances leading to decreased GFR

Question 29

ATI diagnosis

Answer 29

history: is there event that may have caused it? FeNa>2, progressive rise in Cr urinalysis shows muddy brown granular epithelial casts lack of improvement in Cr with IV fluids

Question 30

what is a difference between ATI and prerenal AKI based on Cr?

Answer 30

prerenal AKI BUN:Cr = >20:1 ATI= <15:1 there is a lack of improvement in Cr with IV fluids in ATI, prerenal Cr improves with repletion

Question 31

ATI treatment

Answer 31

supportive care remove nephrotoxic offending agents carefully balance fluid and electrolytes without overloading (depends on urine output)

Question 32

acute glomerulonephritis

Answer 32

intrinsic cause of AKI that is the inflammation and damage of the glomeruli

Question 33

acute GN diagnosis

Answer 33

urinalysis with protein, blood, WBC, RBC cases evidence of other systemic disease **renal biopsy to find out cause

Question 34

acute interstitial damage

Answer 34

acute inflammation of renal tubules and interstitial that can cause intrinsic AKI

Question 35

acute interstitial damage pathophysiology

Answer 35

hypersensitivity reaction usually to drugs or infection that causes inflammation and damage to the interstitial fluid

Question 36

drugs that can cause acute interstitial damage

Answer 36

``` abx PPIs cephalosporins sulfonamides penicillin NSAIDs ```

Question 37

acute interstitial damage physical exam

Answer 37

rash, fever, CVA tenderness

Question 38

acute interstitial damage diagnosis

Answer 38

urinalysis with WBC casts PBS shows eosinophilia renal biopsy shows interstitial T-cell and monocyte infiltration

Question 39

acute interstitial damage treatment

Answer 39

stop the offending rx that is causing reaction (no shit) steroids, IV fluids

Question 40

what can vascular injury cause and how?

Answer 40

can cause intrinsic AKI due to injury to the infrarenal vessels

Question 41

main types of rx that can lead to nephrotoxicity

Answer 41

antibiotics, acyclovir, amphotericin b, MTX, cisplatin, NSAIDs, cyclosporine, iodine and gadolinium contrast

Question 42

causes of vascular injury

Answer 42

HUS, TTP, malignant HTN, vasculitis, atheroembolic disease

Question 43

physical exam findings of vascular injury

Answer 43

petechiae, purpura, livedo reticularis, thromboemboli

Question 44

vascular injury diagnosis and treatment

Answer 44

renal US | treatment to get rid of clot-angioplasty, endovascular tx, thrombolytics

Question 45

post-renal AKI pathophys

Answer 45

acute bilateral urinary flow obstruction leads to increase in intratubular pressure and causes decrease in GFR, can also lead to impaired renal blood flow

Question 46

causes of post-renal AKI

Answer 46

BPH, stones, tumors, neurogenic bladder, iatrogenic like from catheter injury anything that causes bilateral obstruction of urinary flow

Question 47

post renal AKI clinical presentation

Answer 47

- decreased or no urine output - infection or UTI due to obstruction - flank pain if due to stones

Question 48

post-renal AKI diagnosis

Answer 48

renal US or CT scan of abdomen/pelvis showing bladder distention, high postpaid residual volume, stones

Question 49

post-renal AKI tx

Answer 49

relieve obstruction - stents for stones - catheterization - rx for BPH

Question 50

one word for the cause of pre-renal AKI

Answer 50

hypoperfusion

Question 51

two words for the cause of intrinsic AKI

Answer 51

parenchymal damage

Question 52

one word for the cause of post-renal AKI

Answer 52

obstruction

Question 53

hemodynamic support for AKI pt who is hypovolemic

Answer 53

IV fluid resuscitation | consider pressors if pt is very hypotensive

Question 54

hemodynamic support for AKI pt who is hypervolemic

Answer 54

fluid restriction | consider loop diuretics if pt is volume overloaded

Question 55

hemodynamic support for AKI pt who is euvolemic or unknown volume status

Answer 55

try administering a small amount of IV fluid and seeing if pt is responsive

Question 56

most widely used classification system for AKI

Answer 56

KDIGO- based on SCr and urine output