AKI

Question 1

AKI Definition (KDIGO)

Answer 1

Increase Serum Cr >= 26.5 in 48H

OR

Increase Serum Cr >= 1.5x baseline (in 7 days)

OR

Urine Volume < 0.5ml/kg/h for 6 hours

Question 2

Stages for AKI (KDIGO)

Answer 2

Question 3

Pathophys of AKI

Answer 3

Renal tissue is vulnerable (high metabolic demand, marginal oxygenation)

Insult to tissue (Ischamic or toxic)

Possible endothelial/ epithelial injury

Maladaptive repair processes

Question 4

Causes of Pre-Renal AKI

Answer 4

ECF volume depletion - GI loss - REnal Loss - Haemorrhage - 3rd spacing Reduced effective blood volume - Low CO - Low PVR - hepatorenal syndrome RAS issues Drugs

Question 5

Causes of Renal AKI

Answer 5

Glomerular Pathologies - glomerulonephropathies Tubular Pathologies - ATN (toxic/ ischaemic) Interstitial Pathologies - Acute Interstitial nephritis Vascular Pathologies - acute microvascular disease (HUS/ TTP, DIC, anti-phospholipid syndrome, systemic sclerosis, emboli)

Question 6

Causes for ATN (Acute Tubular Necrosis)

Answer 6

Ischaemic Toxic - Endotoxins (myoglobin, casts) - Exotoxins (aminoglycosides, IV contrast, chemotherapies)

Question 7

Common Exotoxins -> ATN

Answer 7

aminoglycosides, IV contrast, chemotherapies

Question 8

What do oliguria/ polyuria indicate in ATN?

Answer 8

Oliguria predictor for dialysis Polyuria heralds renal recovery (occurs before sCr improvements)

Question 9

Causes for Acute Interstitial Nephritis?

Answer 9

Drugs - beat-lactams - PPIS - NSAIDs - Immunotherapy Infection Immune-Mediated - Sjorgen’s - Sarcoidosis - IgG4 Disease Idiopathic

Question 10

Causes for AKI

Answer 10

Thrombotic Microangiopathy (HUS/ TTP) DIC Anti-phospholipid syndrome Systemic Sclerosis Cholesterol Emboli

Question 11

Causes for Post-Renal AKI?

Answer 11

Obstruction at: - PUJ, Ureter, Bladder, Prostate, Urethra Neurological issues

Question 12

in AKI if eospniphilia found

Answer 12

suspicious for AIN, EGPA, cholesterol emboli

Question 13

in AKI if high urate found

Answer 13

suspicious for tumour lysis syndrome

Question 14

Purpose of Uninary Na/ FeNA in AKI

Answer 14

differentiate between renal hypoperfusion and established ATN

Question 15

Cause for hyaline casts in urine?

Answer 15

reduced renal perfusion -> sluggish flow Seen in exercise, dehydration (not associated with pathology) (composed of uromodulin, in loop of henle)

Question 16

Cause for Renal Tubular Epithelial Cell (RTEC) casts in urine?

Answer 16

suggestive of ATN (ischaemic or toxic) - can just have these cells present

Question 17

Cause for granular casts in urine?

Answer 17

Suggestive of ATN (degraded lysosymes with degenerated RTECs)

Question 18

Cause for white cell casts in urine?

Answer 18

Suggestive of AIN in right scenaria Easily confused with RTEC cases, rarely seen in isolation

Question 19

Cause for RBC casts in urine? (and dysmorphic RBCs)

Answer 19

Glomerular Haemorrhage, characteristic of proliferative glomerular lesion

Question 20

Indications for Kidney Biopsy

Answer 20

Active urinary sediment Heavy proteinuria Unclear Aetiology or to confirm diagnosis, exclude dual pathologies