AKI

Question 1

Def of AKI?

Answer 1

Significant decline in renal function over hrs or days manifesting as an abrupt and sustained ↑ in Se U and Cr

Question 2

General classification of kidney injury?

Answer 2

Pre
Renal
Post

Question 3

Pre-renal causes of kidney injury?

Answer 3

Commonest

• Shock
• renovascular compromise (e.g. NSAIDs, ACEi)

Question 4

Renal causes of AKI?

Answer 4

1. Acute Tubular Necrosis (ATN)
2. Acute tubulointersitial nephritis (TIN): drug hypersensitivity
3. Nephritic syndrome

Question 5

Causes of Acute Tubular Necrosis (ATN)?

Answer 5

• Ischaemia: shock, HTN

- Direct nephrotoxins: drugs, contrast, Hb

Question 6

Post renal causes of AKI?

Answer 6

SNIPPIN

• Stone
• Neoplasm
• Inflammation: stricture
• Prostatic hypertrophy
• Posterior urethral valves
• Infection: TB, schisto
• Neuro: post-op, neuropathy

Question 7

Presentation of AKI?

Answer 7

• Uraemia / Azotaemia (nitrogen)
• Acidosis
• Hyperkalaemia
• Fluid overload

Question 8

Investigations of AKI?

Answer 8

ABG: hypoxia (oedema), acidosis, ↑K+
ECG: hyperkalaemia
CXR: pulmonary odeam
Renal US: hydronephrosis

Question 9

Pre renal failure Osmolality and Na levels?

Answer 9

urine is concentrated and Na is
reabsorbed →
- ↑osmolality,
- Na <20mM

Question 10

What is RIFLE classification of AKI?

Answer 10

• 3 grades of AKI (risk, injury, failure)
• 2 outcomes (loss or end-stage kidney disease, ESKD)
• Classification determined by worst criteria

Question 11

Risk class of RIFLE classification creatinine, GFR, and urine output levels?

Answer 11

• ↑Cr x1.5 ↓GFR >25%

- <0.5ml/kg/h x 6h

Question 12

Injury class of RIFLE classification creatinine, GFR, and urine output levels?

Answer 12

• ↑Cr x 2 ↓GFR >50%

- <0.5ml/kg/h x 12h

Question 13

Failure class of RIFLE classification creatinine, GFR, and urine output levels?

Answer 13

• ↑Cr x 3 ↓GFR >75%

- <0.3ml/kg/h x 24h, or anuria x12h

Question 14

Definition of Loss outcome of RIFLE classification?

Answer 14

Persistent acute renal failure = complete loss of function >1mo

Question 15

Definition of end-stage kidney disease (ESKD) outcome of RIFLE classification?

Answer 15

complete loss of function >3mo

Question 16

General management of AKI?

Answer 16

• Stop nephrotoxins: NSAIDs, ACEi, gent, vanc

- Stop metformin if Cr > 150mM

Question 17

ECG features of hyperkalaemia?

Answer 17

• Peaked T waves
• Flattened P waves
• ↑ PR interval
• Widened QRS

Question 18

Management of hyperkalaemia?

Answer 18

1. 10ml 10% calcium gluconate
2. 100ml 20% glucose + 10u insulin (Actrapid)
3. Salbutamol 5mg nebulizer
4. Calcium resonium 15g PO or 30g PR
5. Haemofiltration (usually needed if anuric)

Question 19

Primary management of pulmonary oedema in AKI?

Answer 19

1. Sit up and give high-flow O2
2. Morphine 2.5mg IV (± metoclopramide 10mg IV)
3. Frusemide 120-250mg IV over 1h
4. GTN spray ± ISMN IVI (unless SBP <100)

Question 20

If no response to primary management of pulmonary oedema, what’s the Rx?

Answer 20

Consider

• CPAP
• Haemofiltration / haemodialysis ± venesection

Question 21

Indications for acute dialysis of AKI patients?

Answer 21

1. Persistent hyperkalaemia (>7mM)
2. Refractory pulmonary oedema
3. Symptomatic uraemia: encephalopathy, pericarditis
4. Severe metabolic acidosis (pH <7.2)
5. Poisoning (eg aspirin)

Question 22

Overview of fluid assessment?

Answer 22

1. cardiovascular:
2. Tissues
3. end organ:

Question 23

CVS signs of fluid overload?

Answer 23

Postural BP,
Raised JVP,
High HR

Question 24

Tissue signs of fluid overload

Answer 24

• Cap refill,
• cold/warm hands,
• skin turgor,
• mucous membranes

Question 25

End organ signs of fluid overload

Answer 25

- urine output, | - mental state

Question 26

Triple whammy hit drugs for kidneys?

Answer 26

Avoid if possible: 1. ACEi or angiotensin II inhibitors (sartan) 2. Diuretics 3. NSAIDS or COX 2 inhibitors