4. AKI

Question 1

What is an AKI and how is it measured?

Answer 1

Sudden drop in kidney function measured by creatinine increase or drop in urine output

Question 2

What are the 3 possible criteria to diagnose AKI?

Answer 2

1. Creatinine rises by more than 25 micromol/litre in 48h
2. Creatinine rises by more than 50% in 7 days
3. Urine output is less than 0.5 ml/ kg/ h for more than 6 hours

Question 3

In which 2 groups of patients should you always worry about AKI?

Answer 3

1. Patients who are acutely ill

2. Anyone undergoing an operation

Question 4

RF for AKI?

Answer 4

1. CKD
2. HF
3. Diabetes
4. Liver disease
5. Age over 65
6. Cognitive impairment
7. Nephrotoxic medication (NSAIDS/ ACEi)
8. Contrast medium

Question 5

Causes of AKI can be split into 3 groups which are …

Answer 5

Pre-renal
Renal
Post-renal

Question 6

What do pre-renal causes of AKI have in common and what are they?

Answer 6

Cause reduced blood flow to kidney

Hypotension: due to dehydration or shock

Heart failure

Question 7

What do renal causes of AKI have in common and what are they?

Answer 7

All are due to intrinsic kidney damage

Glomerulonephritis

Interstitial nephritis

Acute tubular necrosis

Question 8

What do post-renal causes of AKI have in common and what are they?

Answer 8

Due to obstruction of urine outflow, causing urine backflow into kidney and subseqent damage

Kidney stones
GU masses
Uretal stricture
Prostatic hypertrophy

Question 9

If someone has an AKI, what tests and investigations should be done?

Answer 9

Urinalysis for blood, protein, leukocytes, nitrates and glucose

US urinary tract to look for post-renal cause of AKI, if urinalysis does not find one

Question 10

Urinalysis indicates infection if …

Answer 10

Nitrates and leukocytes +ve

Question 11

Urinalysis indicates acute nephritis if …

Answer 11

Blood and protein +ve

Question 12

What would suggest diabetes is causing AKI?

Answer 12

Urinary glucose

Question 13

Management of AKI

Answer 13

Correct underlying cause:

e. g. fluid rehydration via IV fluids if pre-renal cause
e. g. relieve obstruction via catheterisation in post-renal cause

Review medication: remove nephrotoxic medication such as NSAIDS and ACEI (because they reduce filtration pressure)

In severe AKI specialist input may be required for dialysis

Question 14

Complications of AKI?

Answer 14

Hyperkalemia

Fluid overload leading to HF and pulmonary edema

Metabolic acidosis

Uremia (leading to encephalopathy and pericarditis)

Question 15

Which 3 conditions cause glomerulonephritis?

Answer 15

Diabetes

SLE

Vasculitis

Question 16

Which 2 classes of drugs cause interstitial nephritis?

Answer 16

NSAIDS

Antibiotics

Question 17

What causes acute tubular necrosis?

Give 2 examples

Answer 17

Ischaemia secondary to stroke (bleeding out and reducing CO) and MI (HF)