AKI

Question 1

AKI refers to a rapid drop in kidney function, diagnosed by…

Answer 1

measuring serum creatinine

Question 2

NICE guidelines state that AKI should be diagnosed if there is a rise in _____ of more than __ micromol/l in __ hours

Answer 2

creatinine
25 micromol/l in 48 hours

Question 3

NICE guidelines state that AKI should be diagnosed if there is a rise in _____ of more than __ % is _ days

Answer 3

creatinine
50% in 7 days

Question 4

NICE guidelines state that AKI should be diagnosed if there is urine output of …. over at least _ hours

Answer 4

<0.5ml/kg/hour over at least 6 hours

Question 5

What are risk factors for AKI?

Answer 5

Aged >65
Sepsis
CKD
HF
Diabetes
Liver disease
Cognitive impairment (meaning reduced fluid intake)
Meds (eg NSAIDs, diuretics, ACE inhibitors)
Radiocontrast agents

Question 6

What are the brackets of causes of AKI?

Answer 6

Pre-renal
Renal
Post-renal

Question 7

What are pre-renal causes of AKI about?

Answer 7

Insufficient blood supply to kidneys resulting in reduced filtration of blood
eg Dehydration
Shock
Heart failure

Question 8

What are renal causes of AKI?

Answer 8

Acute tubular necrosis
Glomerulonephritis
Acute interstitial nephritis
Haemolytic uraemic syndrome
Rhabdomyolysis

Question 9

What do most post-renal causes of AKI involve?

Answer 9

Obstruction to the outflow of urine away from kidneys.
eg Renal stones
Tumours (bladder, prostate)
Strictures of ureters/urethra
BPH
Neurogenic bladder

Question 10

Acute tubular necrosis refers to the damage and death of what?

Answer 10

The epithelial cells of the renal tubules.

Question 11

What can cause acute tubular necrosis?

Answer 11

Ischaemia due to hypoperfusion (dehydration, shock, HF)
Nephrotoxins (eg gentamicin, radiocontrast, cisplatin)

Question 12

What confirms acute tubular necrosis?

Answer 12

Muddy brown casts on urinalysis

Question 13

Is acute tubular necrosis reversible?

Answer 13

Yes, the renal tubular epithelial cells can regenerate usually within 1-3 weeks.

Question 14

True or false: Acute interstitial nephritis is the most common cause of AKI?

Answer 14

False
Acute tubular necrosis is

Question 15

What causes acute interstitial nephritis?

Answer 15

Acute inflammation of space between tubules and vessels is caused by an immune reaction
Drugs (NSAIDs, antibiotics)
Infections
Autoimmune conditions like sarcoidosis or SLE

Question 16

WHat investigation is needed in AKI?

Answer 16

Urinalysis
protein, blood, leucocytes, nitrites and glucose

Question 17

What in the urine suggests infection?

Answer 17

Leucocytes and nitrites

Question 18

What in the urine suggests acute nephritis (or infection)?

Answer 18

Protein and blood

Question 19

What in the urine suggests diabetes?

Answer 19

Glucose

Question 20

Other than urinalysis, what investigation may be done in AKI?

Answer 20

USS of urinary tract to assess obstruction

Question 21

How is AKI managed?

Answer 21

Avoiding nephrotoxic meds where possible
Ensure good fluid intake
Additional fluids before and after any radiocontrast agents.
Withhold any meds that may accumulate with the reduced renal function (eg opiates, metformin)
Relieve obstruction eg catheterisation
If severe, dialysis.

Question 22

What are complications of AKI?

Answer 22

Fluid overload, HF and pulmonary oedema
Hyperkalaemia
Metabolic acidosis
Uraemia leading to encephalopathy and pericarditis