Acute Kidney Injury (AKI)

Question 1

What is an AKI?

Answer 1

Acute Kidney Injury - an acute drop in kidney function.

Question 2

NICE Criteria for an AKI (3).

Answer 2

1. Rise in Creatinine by 25+ umol/L in 48 hours.
2. Rise in Creatinine by 50+% in 7 Days.
3. Oliguria for 6 hours.

Question 3

What is Oliguria?

Answer 3

Urine Output Less than 0.5ml/kg/hour.

Question 4

What is Stage I AKI?

Answer 4

Basic NICE Criteria for an AKI.

Question 5

What is Stage II AKI?

Answer 5

1. Rise in Creatinine by 2.0-2.9x baseline.

2. Oliguria for 12 hours.

Question 6

What is Stage III AKI?

Answer 6

1. Rise in Creatinine by 3.0+x baseline.
2. Increase in Creatinine by 353.6 umol/L.
3. Reduction in Urine Output to less than 0.3ml/kg/hour for more than 1 day.

Question 7

Risk Factors of AKI (6).

Answer 7

1. Acute Illness/Surgery.
2. CKD or HF.
3. Diabetes.
4. Liver Disease.
5. Ageing & Cognitive Impairment.
6. Nephrotoxic Medications

Question 8

Drugs with Nephrotoxic Potential.

Answer 8

1. NSAIDs.
2. Aminoglycosides.
3. ACE Inhibitors.
4. Angiotensin-Receptor Blockers.
5. Diuretics.
6. Iodinated Contrasts.

Question 9

Aetiology of AKI (3).

Answer 9

1. Pre-Renal : inadequate blood supply to kidneys reduces filtration of blood (commonest).
2. Renal : intrinsic disease in the kidney leads to reduced filtration of blood.
3. Post-Renal : obstruction to the outflow of urine from the kidney causes back-pressure into the kidney (obstructive uropathy).

Question 10

Pre-Renal Causes of AKI (4).

Answer 10

1. Hypovolaemia (e.g. Dehydration, Diarrhoea, Vomiting).
2. Hypotension.
3. Heart Failure.
4. Renal Artery Stenosis.

Question 11

Renal Causes of AKI (5).

Answer 11

1. Glomerulonephritis.
2. Acute Interstitial Nephritis.
3. Acute Tubular Necrosis.
4. Rhabdomyolysis.
5. Tumour Lysis Syndrome.

Question 12

Post-Renal Causes of AKI (4).

Answer 12

1. Kidney Stones.
2. Masses e.g. Cancer in Abdomen, Pelvis.
3. Ureteric/Urethral Strictures.
4. Enlarged/Cancerous Prostate.

Question 13

Clinical Consequences of Renal Failure.

Answer 13

1. Oliguria.
2. Fluid Overload.
3. Increased Concentration of Certain Molecules.

Question 14

Clinical Features of AKI (4).

Answer 14

1. Oliguria.
2. Pulmonary/Peripheral Oedema.
3. Arrhythmias.
4. Uraemia Features.

Question 15

Investigations of AKI (3).

Answer 15

1. Urinalysis.
2. Bloods - NICE Criteria.
3. Ultrasound - Obstruction within 24 hours if no identifiable cause.

Question 16

What can Urinalysis indicate? (3).

Answer 16

1. Infection : Leucocytes, Nitrites.
2. Acute Nephritis : Protein, Blood.
3. Diabetes : Glucose.

Question 17

Distinguishing Between AKI and CKD (5).

Answer 17

A : Renal US : CKD have bilateral small kidneys except in :

1. ADPKD.
2. Diabetic Nephropathy.
3. Amyloidosis.
4. HIV-Associated Nephropathy.

B: Hypocalcaemia in CKD.

Question 18

Management of AKI (3).

Answer 18

1. Avoid Nephrotoxic Drugs e.g. NSAIDs, Antihypertensives.
2. Fluid Rehydration (Especially in Pre-Renal).
3. Obstruction Relief : Catheter.

Question 19

What medications should be stopped in an AKI despite not worsening the AKI itself? (3)

Answer 19

• Renally-Excreted Drugs :
  1. Metformin.
  2. Lithium.
  3. Digoxin.

Question 20

When is Renal Replacement Therapy indicated?

Answer 20

No response to medical treatment of complications :

1. Hyperkalaemia.
2. Pulmonary Oedema.
3. Acidosis (Metabolic).
4. Uraemia.