Acute Kidney Injury

Front 1

An abrupt (within 48 hrs) reduction in kidney function currently defined as an absolute increase in serum creatinine

Back 1

acute kidney injury

Front 2

3 causes of ARF

Back 2

1) Pre-renal: problem with renal perfusion

2) Renal: Damage of renal parenchyma

3) Post-renal: obstruction of urine flow

Front 3

Consequence of ARF

Back 3

Fluid retention - volume overload
Electrolyte imbalance
Buildup of toxins - uremia

Front 4

Cystatin C: low molecular weight protein produced at a constant rate by all nucleated cells, free filtered, not secreted
Neutrophil gelatinase-associated lipocalcin (NGAL)
25 kD protein of unknown significance in the kidney
Increases in the urine early in the course of AKI
IL-18, proinflammatory cytokine generated by caspase-1-mediated cleavage in injured proximal tubules


All are what?

Back 4

More sensitive ways than creatinine to measure AKI

Front 5

T/F There may be injury to kidney that don't affect GFR

Back 5

T. May be affecting tubular function

Front 6

T/F Creatinine is a good way to measure tubular injury

Back 6

F

Front 7

T/F Post-renal ARF (urinary tract obstruction) must be bilateral

Back 7

T (unless there was only a single functioning kidney to start)

Front 8

Regarding post-renal ARF - what do you think of in men? women?

Back 8

Prostate; Uterus cancer

Front 9

Complete obstruction of urinary tract causes what?

Back 9

ARF with anuria

Front 10

What sx will obstruction present with?

Back 10

May present with NO symptoms, but may also have suprapubic pain, urge to void, or severe pain with hematuria

Front 11

How to exclude obstruction?

Back 11

Bladder catheterization and renal ultrasonography

Front 12

If not recognized and corrected, what problems will obstruction cause?

Back 12

Pressure-induced and mild ischemic tubular injury, compromising ability to conserve Na and concentrate urine.

Front 13

Common causes of prerenal ARF

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INADEQUATE RENAL PERFUSION.

Volume depletion/hypovolemia.
Impaired cardiac function
Vascular disease
Increased renal vascular resistance

Front 14

If not tx, what happens to kidney in ARF?

Back 14

Ischemic injury

Front 15

T/F All causes of prerenal ARF result in renin, aldosterone, and ADH release

Back 15

T. In the setting of low GFR and normal tubules, kidney will avidly reabsorb water and sodium and have low urine output.

Remember the problem is not with the kidney - it is working its hardest - it's with the blood flow before the kidney.

Front 16

Most reliable sign of severe volume depletion

Back 16

Orthostatic hypotension

Front 17

Hepatorenal syndrome: what is it?

Back 17

condition in which there is progressive kidney failure in a person with cirrhosis of the liver. It is a serious and often life-threatening complication of cirrhosis.

Front 18

Hepatorenal syndrome: how to treat?

Back 18

maintaining patient with dialysis in hopes liver will improve or can get liver transplant

Front 19

NSAIDS: how affect kidneys?

Back 19

1) By blocking COX and PGs (vasodilators), induce pre-renal ARF in settings where there is already renal stress.

2) Decr renal blood flow and GFR, cause retention of sodium, decrease K excretion, impair water excretion.

Front 20

NSAIDS: what conditions can they worsen?

Back 20

HTN, edema formation, hyperkalemia, ARF

(can also cause interstital nephritis with nephritic syndrome)

Front 21

What effects does renal artery stenosis have on kidney?

Back 21

Induces secretion of RAA

Front 22

Renal causes of ARF

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Intrinsic glomerular disease.

Vascular disease.

Acute tubular necrosis

Acute interstitial nephritis

Front 23

Acute Tubular Necrosis: what is it?

Back 23

Results from intense renal vasoconstriction in ischemia that lower renal blood flow 50-90% and decreased pressure below that required for filtration formation.

Front 24

Acute Tubular Necrosis: what does it look like under urinalysis?

Back 24

Mild proteinuria, coarse granular casts, renal tubular epithelial casts/cells. NO RBC casts

Plasma osmolality is close to urine osmolality (indicating loss of urine concentrating ability).

Low urine-plasma creatinine ratio

Front 25

What is usually cause of death in Acute Tubular Necrosis?

Back 25

That which caused the ATN - infection, hemorrhage, etc.

Front 26

Prevention of ATN

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Avoid hemodynamic instability and toxins.

Osmotic diuretic, loop diuretics and administering natriuretic peptides and dopamine may minimize severity of and hasten recovery from ATN.

Front 27

Mechanisms of nephrotoxicity from drugs

Back 27

Renal vasoconstriction - cyclosporine, radiocontrast material, amphotericin B

Intratubular precipitation: acyclovir,sulfathiazole

Acute Tubular Necrosis: Aminoglycosides, heavy metals

Front 28

Amphotericin B causes what kidney disorder?

Back 28

Distal renal tubular acidosis

Front 29

Cisplatin causes what kidney disorder?

Back 29

Magnesium wasting

Front 30

Mechanism of aminoglycoside-induced acute renal failure

Back 30

Aminoglyc. are freely filtered, most is then excreted, but a small amount is stored in tubular cells (especially prox tubule).

Causes acute tubular necrosis

Front 31

Prevention of aminoglycoside-induced acute renal failure

Back 31

Minimize duration of therapy, adjust dose if renal function is impaired, monitor drug levels.

Front 32

Mechanism of radiocontrast nephropathy

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Mechanism not entirely understood.

2 theories
1) Vasoconstriction induced by contrast-mediated alteration in NO or endothelin production
2) Direct toxic effect of contrast on renal tubules caused by generation of free radicals.

See a small rise in creatinine with administration.

Front 33

Prevention of radiocontrast nephropathy

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Avoid contrast when possible.

Avoid dehydration and NSAIDs prior to contrast administration.

Hydrate it no contraindicated.

Bicarb may reduce risk.

N-acetylcysteine reduces risk.

Front 34

Acute Interstitial Nephritis was almost exclusively associated with what?

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Infectious diseases like diphtheria and scarlet fever.

Front 35

Current associations with Acute Interstitial Nephritis

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hypersensitivity to drugs

Front 36

Clinical features of Acute Interstitial Nephritis

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Abrupt, severe deterioration in renal function.

May have flank pain, malaise, hematuria, drug rash, eosinophilia.

Front 37

Acute Interstitial Nephritis: what's found in the urine?

Back 37

WBC, WBC cases, some proteinuria

Front 38

T/F Think Post and Pre-renal causes of ARF first

Back 38

T

Front 39

What is the general idea in tx of ARF?

Back 39

Prevent complications related to accumulation of excess fluid and waste products.

May need to use dialysis until kidney fxn returns.

Front 40

Most common cause of AKI?

Back 40

Prerenal

Front 41

What do these have in common?
hepatorenal syndrome
NSAIDs

Back 41

Cause increase renal vascular resistance and perfusion injury

Front 42

Clinical manifestations of prerenal AKI

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10% weight loss (if no edema) - excellent
orthostatic hypotension - good
dry skin & buccal mucosa - unreliable

Front 43

Hepatorenal syndrome has Features of pre-renal AKI except

Back 43

inadequate response to volume expansion
inadequate response to increased blood pressure

Front 44

Pharmacological (ie., non transplant) tx of hepatorenal syndrome

Back 44

Pharmacologic treatment: Vasopressin analogues (systemic vasoconstriction), Octreotide (splanchnic vasoconstrictor) + midodrine, NE, TIPS

Front 45

What will the specific gravity of urine be in

1) Pre-renal ARF
2) Renal ARF

Back 45

1) >1.020
2) ~1.010

Front 46

What will the osmolality of urine be in
1) Pre-renal ARF
2) Renal ARF

Back 46

1) >500
2) <500