3.1. Kidney Injury - Acute Kidney Injury

Question 1

What is Acute Renal Disease?

Answer 1

The Rapid loss of Glomerular Filtration and Tubular Function over hours-days.

Question 2

What fraction of Hospital admissions are complicated by this?

Answer 2

1/7

Question 3

What are risk factors for developing an Acute Kidney Injury?

Answer 3

1. Age

2. Underlying predisposign conditions (e.g. Diabetes)

Question 4

What are the 3 types of Renal Disease?

Answer 4

1. Pre-Renal - Blood Flow to the Kidney (Common)
2. Renal (Intrinsic) - Damage to the Kidney Parenchyma
3. Post-Renal - Obstruction to the Urine Exit (Common)

Question 5

What are causes of Pre-Renal Acute Kidney Injury?

Answer 5

1. Sepsis - Major contributor (50% of cases of AKI)
2. Hypotension / Renal Artery Occlusion
3. Hypovolaemia / Shock
4. Hepato-renal Syndrome (Liver Failure)
5. Congestive Cardiac Failure

Question 6

What are causes of Renal Acute Kidney Injury?

Answer 6

1. Acute Tubular Injury
2. Tubulointerstitial Injury
3. Glomerulonephritis
4. Myeloma
5. Vasculitis

Question 7

What are causes of Post-Renal Acute Kidney Injury

Answer 7

1. Kidney Stones
2. Intramural Obstruction
3. Extramural Obstruction

Question 8

What are some aetiologies of Hypovolaemia (causing Pre-Renal Acute Kidney Injury)?

Answer 8

1. Haemorrhage
2. Burns
3. Diuretics
4. Vomiting / Diarrhoea

Question 9

What are some aetiologies of Acute Tubular Injury (causing Renal Acute Kidney Injury)?

Answer 9

1. Ischemia
2. Pre-Renal Acute Kidney Injury
3. Nephrotoxins

Question 10

What is a cause of Tubulointerstitial Injury (causing Renal Acute Kidney Injury)?

Answer 10

Acute Interstitial Nephritis

Question 11

What are some aetiologies of Vasculitis (causing Renal Acute Kidney Injury)?

Answer 11

1. Lupus

2. Anti-Neutrophil Cytoplasmic Antibodies (ANCA)

Question 12

What are some aetiologies of Kidney Stones (causing Post-Renal Acute Kidney Injury)?

Answer 12

1. Calculus
2. Clot
3. Sloughed Papilla

Question 13

What are some aetiologies of Intramural Obstruction (causing Post-Renal Acute Kidney Injury)?

Answer 13

1. Malignancy
2. Ureteric Stricture
3. Prostatic Disease

Question 14

What are some aetiologies of Extramural Obstruction (causing Post-Renal Acute Kidney Injury)?

Answer 14

1. Retroperitoneal Fibrosis

2. Malignancy

Question 15

What are the 4 Stages in the course of Acute Kidney Injury?

Answer 15

1. Preventative Stage
2. Management Stage
3. Complications
4. Death

Question 16

What is the Preventative Stage?

Answer 16

There is a Normal Kidney which may be exposed to increase risk of Kidney Disease

Question 17

What is the Management Stage?

Answer 17

Damage has occurred to the Kidney resulting in a decreased Glomerular Filtration Rate.
Note - This can lead to Complications and Kidney Failure

Question 18

What is the Complications Stage?

Answer 18

These include the list of Complications which can occur due to the Acute Kidney Injury

Question 19

Why can Death Occur?

Answer 19

Due to the Kidney Failure, or the Complications associated with the damage to the Kidney

Question 20

When the Injury is initiated, what is it initiated by? And is the Acute Kidney Injury still preventable?

Answer 20

The aetiology (e.g. Toxins / Ischemic Insult)
It is still potentially preventable as the Renal Parenchymal Injury will still need (and continue) to evolve

Question 21

When is the patient usually maximally oliguric?

Answer 21

During the management stage when established Parenchymal Injury has occurred

Question 22

Does the Kidney have the potential to regenerate?

Answer 22

Yes, resulting in a gradulal increase in urine output and decrease in serum creatinine

Question 23

What are the Clinical Features of Acute Kidney Injury?

Answer 23

1. Rapid Loss of Glomerular Filtration
2. Rapid Loss of Tubular Function
3. Retention of Urea
4. Retention of Creatinine
5. Oliguria

Question 24

What investigations are necessary for Acute Kidney Injury?

Answer 24

1. Detailed History / Examination
2. Blood Tests
3. Urinalysis (Urine Dipstick)
4. Ultrasound Scan
5. Renal Biopsy

Question 25

What is the purpose of a Detailed History / Examination?

Answer 25

1. To identify the insult (i.e. Drug) | 2. To observe the Fluid Status / Urinary Obstruction etc

Question 26

What Blood Tests will be Performed?

Answer 26

1. Serum Creatinine 2. Full Blood Count 3. Urea and Electrolytes (Including Bicarbonate and Calcium) 4. Liver Function Test (and Biochemistry) 5. Coagulation Screen 6. Arterial Blood Gas 7. Serum Anti-Neutrophil Cytoplasmic Antibodies test

Question 27

What is the purpose of the Blood Tests?

Answer 27

1. To assess renal function (serum creatinine) | 2. To try to identify any other potential cause

Question 28

What is the purpose of the Urinalysis (Urine Dipstick)?

Answer 28

To identify Haematuria, and Proteinuria

Question 29

What is the purpose of the Ultrasound Scan?

Answer 29

To try and find any Post-Renal causes of Acute Kidney Injury

Question 30

What is the purpose of the Renal Biopsy?

Answer 30

To confirm the Diagnosis

Question 31

How many stages are there in the KDIGO (Kidney Disease; Improving Global Outcomes) classification?

Answer 31

3

Question 32

What is defined as a Stage 1, in the KDIGO (Kidney Disease; Improving Global Outcomes) classification, in terms of Creatinine / Urine Output?

Answer 32

Serum Creatinine: a) 1.5 - 1.9 x the baseline OR b) Greater than 26.5 μmol/l increase Urine Output: Less than 0.5ml/kg/h for 6 - 12 hours

Question 33

What is defined as a Stage 2, in the KDIGO (Kidney Disease; Improving Global Outcomes) classification, in terms of Creatinine / Urine Output?

Answer 33

Serum Creatinine: a) 2.0 - 2.9 x the baseline Urine Output: Less than 0.5ml/kg/h for more than 12 hours

Question 34

What is defined as a Stage 3, in the KDIGO (Kidney Disease; Improving Global Outcomes) classification, in terms of Creatinine / Urine Output?

Answer 34

``` Serum Creatinine: a) more than 3.0 x the baseline OR b) An incraesed to 354μmol/l OR c) Initiation of Renal Replacement Therapy ``` Urine Output: Less than 0.5ml/kg/h for 6 - 12 hours

Question 35

What are the Treatments of Acute Kidney Injury?

Answer 35

1. Anticipation and Prevention of AKI 2. Treat the Underlying Cause (e.g. stop nephrotoxic drugs) 3. Specific Treatments a) Pre-Renal b) Renal c) Post-Renal 4. Renal Replacement Therapy

Question 36

What is included in the Pre-Renal Specific Treatments?

Answer 36

1. Fluid Balance - Volume Resuscitation / Fluid Restriction | 2. Blood Pressure Support - Vasopressors / Stop Anti-Hypertensives

Question 37

What is included in the Renal Specific Treatments?

Answer 37

Removal of the Precipitant: 1. Treat Sepsis 2. Stop taking causative Drugs 3. Diagnosis of Glomerulonephritis made

Question 38

What is included in the Post-Renal Specific Treatments?

Answer 38

1. Haemodialysis - Solute removal by diffusion (intermittent therapy) 2. Haemofiltration - Solute removal by convection (continuous therapy)

Question 39

What acronym does the overall treatment of Acute Kidney Injury follow? And what does it stand for?

Answer 39

``` STOP: Sepsis Toxins Optimize Blood Pressure Prevent Harm ```

Question 40

What Complications fall under the "Prevent Harm" section of the "STOP" acronym for the management of Acute Kidney Injuries?

Answer 40

``` A, E, I, O, U: Acidosis Electrolyte Imbalance (Hyperkalaemia) Intoxication (Toxins - Use antidote / RRT) Overload (Pulmonary Oedema) Uraemic Complications (Pericarditis) ```