Case 1 - AKI

Question 1

How is AKI staged?

Answer 1

Creatinine levels OR urine output

Question 2

Acute tubular necrosis vs pre-renal cause of uraemia

Answer 2

Question 3

Risk of fatality of AKI

Answer 3

Similar to that of MI

Question 4

What does creatinine levels depend on?

Answer 4

Production - eg if large muscle mass breakdown levels will be higher
Poor kidney function - not clearing

Question 5

Why do we use creatinine for AKI?

Answer 5

• More sensitive marker of disease than eGFR
• Produced and excreted at constant rate ish

Question 6

Stage 1 AKI

Answer 6

• 1.5-1.9 baseline creatinine
• OR 0.3mg/dl or more (26.5 umol/l or more)

OR <0.5ml/kg for 6-12hrs urine output

Question 7

Stage 2 AKI

Answer 7

• 2-2.9 x baseline
• OR <0.5mls/kg for 12 hrs or more

Question 8

Stage 3 AKI

Answer 8

• 3x baseline
• OR 4mg/dl or more (353.6umol/L or more)

OR
* <0.3mls/kg for 24hrs or more
* or anuria for 12 hrs

OR
* Renal replacement therapy commenced

Question 9

3 types of causes of an AKI

Answer 9

• Pre renal
• Renal
• Post renal

Question 10

Risk factors for AKI

Answer 10

• Diabetes
• CKD
• IHD/CHF/CVD
• Major medical co-morbiditiy (any)
• Elderly >75
• Sepsis
• Medications - ACEi, ARBs, NSAIDs, Abx

Question 11

Pre-renal causes of AKI

Answer 11

• Hypovolaemia
• Decreased CO
• CHF
• Liver failure
• Impaired renal autoregulation
• NSAIDs
• ACEi/ARBs
• Cyclosporine

Question 12

Intrinsic renal causes of AKI categories

Answer 12

• Glomerular
• Tubules and intersitium
• Vascular

Question 13

Vascular causes of intrinsic AKI

Answer 13

• Vasculitis
• Malignant hypertension
• TTP-HUS (thrombotic thrombocytopenia purpura-haemolytic uraemic syndrome)

Question 14

Tubules and intersitium causes of intrinsic AKI

Answer 14

• Ischaemia
• Sepsis/infection
• Nephrotoxins

Question 15

Examples of exogenous nephrotoxins

Answer 15

• Iodinated contrast
• Aminoglycosides eg gentamicin
• Cisplatin
• Amphotericin B

Question 16

Examples of endogenous nephrotoxins which cause intrinsic AKI

Answer 16

• Haemolysis
• Rhabdomyolysis
• Myeloma
• Intratubular crystals

Question 17

Post renal causes of AKI

Answer 17

• Bladder outlet obstruction
• Bilateral pelvoureteral obstruction (or unilateral if only 1 kidney functioning)

Question 18

Investigations for AKI - bedside

Answer 18

• Urine dipstick - protein and blood
  *

Question 19

Bloods for suspected AKI

Answer 19

• FBC
• U&Es
• LFTs
• Bone profile
• CRP
• Include serum bicarbonate
• CK if suspect Rhabdo

Question 20

What test to do if blood and protein on urine dipstick?

Answer 20

• c-ANCA (PR3) and p-ANCA (MPO) - to look for vasculitis
• Anti GBM, ANA, C3 and C4 - for lupus nephritis
• Serum immunoglobulins and electrophoresis - to look for myeloma

Question 21

Test if suspect post streptococcal glomerulonephritis

Answer 21

• Anti-streptolysin O titres

Question 22

What to consider if AKI with thrombocytopaenia?

Answer 22

• HUS
• TTP
• DIC

Therefore request haemolysis screen

Question 23

Bloods in haemolysis screen

Answer 23

• Blood film
• LDH
• Bilirubin
• Reticulocytes
• Haptoglobin
  and call Renal SpR urgently

Question 24

When to check cryoglobulins?

Answer 24

• Unexplained rash
• Peripheral neuropathy
• Hypocomplementaemia
• Hepatitis C known
• History of lymphoproliferative disorder
• Positive Rh F

Question 25

Management of AKI

Answer 25

* Discontinue nephrotoxic agents * Ensure volume status and perfusion pressure - IV fluids if dehydrated, diuretics if overloaded --> euvolaemia * Third spaced fluids? - overloaded appearance but JVP and BP low * CVP/arterial line for haemodynamic monitoring? * Monitor urine output and daily bloods (catheterise if needed) * Avoid hyperglycaemia * Check for changes needed in drug dosing * Treat cause * Refer specialist if needing renal replacement therapy * Consider ICU admission

Question 26

Indications for RRT

Answer 26

* Hyperkalaemia - resistant to medical therapy * Metabolic acidosis - reistant to medical therapy * Fluid overload - resistant to diuretics * Uraemic pericarditis * Uraemic encephalopathy - vomit, confused, drowsiness, reduced conc * Intoxications - ethylene glycol, methanol, salicyclates, lithium

Question 27

Fluid assessment involves...

Answer 27

* Capillary refill * Skin turgour * Pulse and RR * BP * JVP * Mouth dry? * Auscultate lungs and heart * Abdo - percuss, assess shifting dullness * Sacral and leg oedema * Weight check * Urine output monitoring

Question 28

Drugs to stop in AKI

Answer 28

* Diuretics * Aminoglycosides and ACEi * Metformin * NSAIDs (except aspirin at cardioprotective dose) DAMN | Also remember lithium toxicity risk increases, consider stopping