AKI (Part I) Flashcards

1
Q

What is the risk factor for CKD & ESRF?

A

AKI

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2
Q

What is the definition of AKi?

A
  • Reduced UO < 0.5ml/kg/hr for 6hrs
  • Increased creatinine > 1.5 of baseline in 7 days
  • Increased creatinine > 0.3mg/dL or 26.5 micromol/L in 48hrs
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3
Q

Stimulants from the production of ADH?

A
  • Stress
  • Pain
  • Hypovolaemia
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4
Q

What is KDIGO?

A

Kidney Disease Improving Global Outcomes - Established in 2012

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5
Q

What is AKD ?

A

AkI persisting for > 7 days

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6
Q

What is CKD?

A

AKD persistent until day 90

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7
Q

What is creatinine?

A
  • Metabolite of creatine phosphate
  • Falls in critical illness
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8
Q

What is creatine phosphate?

A

Synthesized from the below in the liver & kidney;

  • Amino acids
  • Glycine
  • Arginine
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9
Q

Creatine phosphate energy potential?

A

Mobilizable reserve of high energy phosphate in skeletal muscles

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10
Q

Determinants of creatinine production?

A
  • Determined by muscle mass
  • Meat intake
  • Amount of creatine generated in the liver & kidney
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11
Q

Limitations of creatinine as a marker for renal function?

A
  • Takes 24-36hrs to rise after renal insult
  • Drug induced change in conc. w/o change in renal function
  • Unreliable in sepsis, liver disease or muscle wasting
  • Affected by volume status - Undiagnosed in hypervolaemia
  • Baseline required
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12
Q

Analytic assessment of creatinine?

A

Jaffe-based assay

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13
Q

Drugs interfering with creatinine?

A
  • Cimetidine - Rise of creatinine
  • Trimethoprim - Rise of creatinine
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14
Q

Conditions causing oliguria?

A
  • Fasting
  • Surgery
  • Stress
  • Hypovolaemia
  • Pain
  • Trauma
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15
Q

Physiologic & pathologic oliguria?

A

See image attached

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16
Q

What is cystatin C?

A
  • Produced by all nucleated cells
  • Low MW facilitating glomerular filtration
  • Reabsorbed in the renal tubules
  • Catabolized in the proximal tubular cells
  • Conc influenced by steroids & thyroid Fx
  • More accurate in critically ill than creatinin
  • Shorter half-life than creatinine
  • Presence in urine is a marker of kidney injury
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17
Q

Furosemide stress test?

A
  • 1mg/kg or 1.5mg/kg if furosemide in last 7 days
  • If UO is < 200ml in 2 hrs - Risk of progression of AKI and RRT
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18
Q

Furosemide action?

A
  • Binds to albumin
  • Actively secreted into the tubular lumen in PCT
  • Delivered to the thick ascending limb of LoH
  • High sensitivity & specificity for RRT
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19
Q

Usefulness of creatinine?

A

It reflects glomerular filtration

20
Q

New biomarkers reflecting tubular stress?

A

TIMP-2 x IGFBP-7

21
Q

New biomarkers reflecting tubular damage?

A
  • NGAL
  • KIM-1
  • L-FABP
22
Q

New biomarkers reflecting tubular inflammation?

A
  • IL-18
  • CCL14
23
Q

What is subclinical AKI?

A

Increase in biomarker levels without increase in creatinine

24
Q

What is functional AKI?

A

Increase in creatinine levels without increase in biomarkers

25
Q

What is subclinical injury?

A

Rise is biomarker levels without increase in creatinine

26
Q

Creatinine - Is it an early or late marker of AKI?

A

This is a late maker of AKI

27
Q

What is the enzyme released from tubular cells after injury in the - Proximal Renal Tubule?

A
  • HRTE-1 (Proximal renal tubular epithelial antigen)
  • Alpha-glutathione S-transferase (Alpha-GST)
  • Pi-glutathione S-transferase (pi-GST)
  • GGT - Gamma-glutamyltranspeptidase
  • AAP - Alanine Aminopeptidase
  • LDH
  • NAG - N-acetyl-beta-glucosaminidase
  • ALP
28
Q

What is KIM-1 (Kidney Injury Molecule) ?

A
  • MW =38.7kDa
  • Type-1-Transmembrane Glycoprotein
  • Undetectable in normal kidney tissue and urine
  • Present after kidney injury
  • Plays a role in renal injury & repair
29
Q

What is interleukin-18?

A
  • It is a 22kDa molecule
  • Pro-inflammatory cytokine
  • Recruits neutrophils during ischaemic injury
30
Q

When is interleukin-18 present in the kidney?

A

Present in the kidney after ischaemic-reperfusion injury

31
Q

Time from injury to detection of interleukin-18 in urine ?

A
  • In the first 6 hours
  • Peaks at 12 - 18 hours
32
Q

What is Neutrophil Gelatinase-associated lipocalin (NGAL)?

A
  • Its is a 25kDa molecule
  • Linked to inflammation & infection
  • Results from tubular production & secretion
  • Freely filtered by glomerulus
33
Q

Time of kidney injury to detection of Neutrophil Gelatinase-associated lipocalin (NGAL) in urine?

A
  • 2 hours after ischaemic or nephrotoxic injury
34
Q

What is the mechanism of action of Neutrophil Gelatinase-associated lipocalin (NGAL) ?

A
  • Binding to iron-siderophore complexes
  • Bacteriostasis by inhibiting iron uptake by bacteria
  • Upregulation of heme oxygenase-1
  • Overall protective action on tubular cells
35
Q

What is the main sites of production of Neutrophil Gelatinase-associated lipocalin (NGAL) ?

A
  • Thick ascending limb of LoH
  • Collecting duct
36
Q

What is the usefulness of Neutrophil Gelatinase-associated lipocalin (NGAL) ?

A
  • Predict the onset of AKI
  • Predict the course of AKI
37
Q

How is Neutrophil Gelatinase-associated lipocalin (NGAL) tested?

A
  • Available as a bedside test
38
Q

What is L-FABP (Urinary Liver-type fatty acid-binding protein) ?

A
  • Gene expressed in the renal cortex
  • It is 14kDa in weight
  • Localized in the PCT
39
Q

What does L-FABP (Urinary Liver-type fatty acid-binding protein) signify?

A
  • Proximal tubular epithelial cell stress
  • Severity of ischaemic tubular injury
  • Elevated after cardiac surgery
40
Q

What is the peak time to identifying L-FABP (Urinary Liver-type fatty acid-binding protein) ?

A
  • This is 6 hours
41
Q

What is urinary Tissue Inhibitor of Metalloproteinases - TIMP & Insulin-like growth factor binding protein (7) - IGFBP7 ?

A
  • Involved in G1 cell cycle arrest
  • Marker of tubular stress
42
Q

Urinary Tissue Inhibitor of Metalloproteinases - TIMP & Insulin-like growth factor binding protein (7) - IGFBP7 are a strong predictor for?

A

Development of KDIGO 2/3 within 12 hours.

43
Q

What are CCL14?

A
  • Member of the chemokine family
  • Role is leukocyte chemotaxis
  • Tissue injury and repair process
44
Q

Properties of CCL14?

A
  • Binds avidly to chemokine receptors
  • Important for monocyte/macrophage recruitment
  • Increased urinary secretion predicts persistent AKI
45
Q

What diseases is CCL14 implicated for proinflammatory chemotaxis ?

A
  • RA
  • Sclerosis
  • Lupus