334 Acute Kidney Injury

Question 1

Common diagnostic features of AKI

Answer 1

Increase in BUN and/or increase in serum crea, reduction in urine volume

Question 2

ICU mortality rates in AKI

Answer 2

May exceed 50%

Question 3

Causes of AKI

Answer 3

Prerenal Azotemia
Intrinsic renal Parenchymal disease
Post renal Obstruction

Question 4

Most comon form of AKI

Inadequate renal plasma flow and intraglomerular hydrostatic pressure

Answer 4

Prerenal Azotemia

Question 5

Common clinical conditions in Prerenal azotemia

Answer 5

Hypovolemia
Dec cardiac output
Medications: NSAIDs, ARBs, ACEi

Question 6

Prolonged periods of prerenal azotemia may lead to ischemic injury termed as

Answer 6

Acute TUbular NEcrosis (ATN)

Question 7

Renal blood flow accounts for _ % of cardiac output

Answer 7

20%

Question 8

This maintains GFR despite decreased renal blood flow by renal efferent vasoconstriction

Answer 8

Angiotensin II

Question 9

This leads to dilataion in the setting of low perfusion pressure therefor maintaining GFR

Answer 9

Myogenic Reflex, prostaglandins, kinins, NO

Question 10

Renal autoregulation usually fails once SBP falls below __ mm Hg

Answer 10

80 mmHg

Question 11

These limits renal afferent vasodilation:

Answer 11

Long standing hpn, hyalinosis, myointimal hyperplasia

NSAIDs

Question 12

These limits renal efferent vasodilation

Answer 12

ACE inhibitors, ARBs

Bilateral renal artery stenosis, unilateral renal artery stenosis

Question 13

This poses a particularly high risk for developing prerenal azotemia

Answer 13

NSAIDs + ACE inhibitors

Question 14

Type of Hepatorenal syndrome in which AKI without an alternate cause PERSISTS despite volume administration and witholding of diuretics

Answer 14

Type 1 HRS

Question 15

This type of Hepatorenal syndrome is less severe form - characterized by REFRACTORY ASCITES

Answer 15

Type 2 HRS

Question 16

Most common causes of intrinsci AKI

Answer 16

Sepsis, ischemia, nephrotoxins

Question 17

Pathophysiology of sepsis-induced AKI

Answer 17

Tubular injury, inflammation, mitochondrial dysfunction and interstitial edema

Question 18

Hemodynamic effects of sepsis in AKI

Answer 18

Generalized arterial vasodilation, expression of NO synthase -> decreased GFR

Question 19

Healthy kidneys recieve _% of cardiac output and account for _% of resting o2 consumption

Answer 19

20% of cardiac output

10% of o2 cosumption

Question 20

One of the most hypxic regions in the body

Answer 20

Renal medulla - outer medulla

Question 21

Most common procedures associated with AKI

Answer 21

Cardiac surgery with bypass, vascular procedures with aortic clamping, intraperitoneal procedures

Question 22

Risk factors for post op AKI

Answer 22

CKD, old age, DM, CHF, Emergency procedures

Question 23

AKI is a complication of burns affecting 25% of individuals with more than _% of Total body surface area

Answer 23

10%

Question 24

Intraabdominal pressure of _mmHG lead to renal vein compression and reduced GFR

Answer 24

20 mmHg

Question 25

Leading cause of AKI

Answer 25

Iodinated contrast agents for CV and CT imaging

Question 26

Clinical course of contrast nephropathy

Answer 26

Rise in SCr 24-48 hrs following exposure, peak of 3-5 days, resolving within 1 week

Question 27

Antibiotics causing tubular necrosis

Answer 27

Aminoglycosides and amphotericin B, mainfests after 5-7 days of therapy

Question 28

Common finding in antibiotic induced AKI

Answer 28

Hypomagnesemia

Question 29

Amphotericin B causes AKI by

Answer 29

renal vasoconstriction from increased tubuloglomerular feedback AND direct tubular troxicity; dose and duration dependent

Question 30

Clinical features of Amphotericin B nephrotoxicity

Answer 30

Hypomagnesemia, hypocalcemia, nongap metabolic acidosis

Question 31

May cause hemorrhagic cystitis and tubular toxicity; type 2 RTA (Fanconi's syndrome), polyuria, hypokalemia and decline in GFR

Answer 31

Ifosfamide

Question 32

Cause of chinese Herb Nephropathy and Balkan Nephropathy

Answer 32

Aristocholic acid

Question 33

Uromodulin, the most common protein in urine and produced in thick ascending loop of henle

Answer 33

Tamm- Horsfall protein

Question 34

Uric acid levels in Tumor lysis syndrome

Answer 34

>15mg/dl

Question 35

Tumor lysis syndrome:electrolyte features

Answer 35

hyperkalemia and hyperphosphatemia and hypocalcemia

Question 36

Occurs when normally unidirectional flow of urine is blocked

Answer 36

Post renal AKI

Question 37

Diagnosis of AKI

Answer 37

Rise from baseline of at least 0.3mg/dl within 48 hours at least 50% higher than baseline wihtin 1 week or Reduction in UO less than 0.5ml/Kg /hr for longer than 6 hours

Question 38

AKI with palpable purpura, pulmonary hemorrhage or sinusitis raises the possibility of

Answer 38

systemic vasculitis with glomerulonephritis

Question 39

AKI from ATN due to ischemic injury, sepsis or certain nephrotoxins has characteristic urine sediment findings of :

Answer 39

"Muddy Brown" Granular casts and tubular epithelial casts

Question 40

Oxalate crystals in AKI should prompt evaluation for

Answer 40

Ethylene glycol toxicity

Question 41

A measure of both the kidney's ability to reabsorb sodium as well as endogenously and exogenously administired factors that affcet tubular reabsorption

Answer 41

Fractional excretion of Na (Fe Na)

Question 42

A type 1 transmembrane protein abundant in proximal tubular cells injured by ischemia or nephrotoxins such as cisplatin/ ichemic or nephrotoxic injury

Answer 42

Kidney injury molecule-1 (KIM-1)

Question 43

NGAL (lipocalin-2 or siderocalin) | Neutrophile gelatinase associated lipocalin

Answer 43

Biomarker of AKI, bind to iron siderophoere an dmay have tissue protective effects; detected in plasma and urine within 2h of Cardiopulmonary bypass- associated AKI

Question 44

Hallmark of AKI

Answer 44

Buildup of nitrogenous waste products, elevated BUN

Question 45

BUN level which causes metal status changes, bleeding complications

Answer 45

>100mg/dl

Question 46

Most concerning complication of AKI

Answer 46

Hyperkalemia

Question 47

Definitive treatment of hepatorenal syndrome

Answer 47

orthotopic liver transplantation

Question 48

Scleroderma renal crisis should be treated with

Answer 48

ACE inhibitors

Question 49

Idiopathic TTP-HUS should be treated promptly with

Answer 49

Plasma exchange

Question 50

Patients with rhabdomyolysis may initially require _L of fluid per day

Answer 50

10L

Question 51

Diuretics may be used if fluid repletion is adequate but unsuccesful in achieving urinary flow rates of _

Answer 51

200-300mL/hr

Question 52

Metabolic acidosis is generally not treated unless severe at pH_ and bicarbonate of _mmol/L

Answer 52

pH <7.20 and bicarbonate at <15mmol/L

Question 53

According to KDIGO, AKI patients should achieve total energy intake of

Answer 53

20-30kcal/kg/day

Question 54

Protein intake in non severe AKI, no need for dialysis

Answer 54

0.8 to 1.0 g/kg/perday

Question 55

Protein intake in patients on dialysis

Answer 55

1.0-1.5 g/kg per day

Question 56

Protein intake if hypercatabolic and receiving CRRT

Answer 56

1.7 g/kg per day

Question 57

Many nephro initiate dialysis for AKI empirically when BUN exceeds:

Answer 57

100 mg/dl

Question 58

Most common form of renal replacement therapy for AKI

Answer 58

Hemodialysis

Question 59

_% may develop ESRD - among survivors of AKI requiring temporary dialysis

Answer 59

10%

Question 60

Case: 60 M with constitutional symptoms, bone pain Lab: Monoclonal spike in urine, low anion gap, anemia

Answer 60

Multiple myeloma

Question 61

Case: Aminoglycosisde antibiotics, cisplatin, antivirals, ethylene glycol ingestion, melamin ingestion Lab: urine sediment: granular casts, renal tubular epithelial cell casts, FeNa >1%

Answer 61

Tubular injury

Question 62

Case: Recent medication exposure with fever, rash , arthralgias Lab: Urine has eosinophilia, sterile pyuria, nonoliguric

Answer 62

Interstitial nephritis

Question 63

Case: Neurologic abnormalities present, recent diarrhea, with AKI, use of calcineurin inhibitors, pregnancy or post partum Lab: schistocytes on PBS, elevated LDH, anemia and decreased plt, ADAMTS13 activity

Answer 63

TTP/HUS Typical HUS - AKI with diarrhea (Shiga toxin, E.coli) Atypical HUS- inherited or acquired complement dysregulation TTP HUS - sporadic cases