Acute Kidney Injury

Question 1

what is AKI

Answer 1

an acute drop in kidney function

diagnosed by measuring serum creatinine

Question 2

NICE criteria for AKI

Answer 2

• rise creatinine 26micromol/l in 48hrs
• rise in creatinine 50% in 7 days
• urine output <0.5ml/kg/hr for >6hrs

Question 3

AKI risk factors

Answer 3

infection 
recent surgery 
CKD 
heart failure 
diabetes
liver diseas
older age >65yrs
cognitive impairment 
nephrotoxic medications e.g. NSAIDs, ACEIs
use of contrast medium e.g. CT scan

Question 4

causes of AKI: pre-renal

Answer 4

most common

inadequate blood supply to kidneys reducing the filtration of blood

• dehydration
• hypotension (shock)
• heart failure

Question 5

causes of AKI: renal causes

Answer 5

glomerulonephritis
interstitial nephritis
acute tubular necrosis

Question 6

causes of AKI: post-renal causes

Answer 6

obstruction to outflow of urine from kidney - obstructive uropathy

• kidney stones
• abdo/pelvic masses
• ureter strictures
• enlarged prostate/prostate Ca

Question 7

AKI investigation s

Answer 7

urinalysis for protein, blood, leucocytes, nitrites and glucose

USS urinary tract to look for obstruction

Question 8

AKI urinalysis: leucocytes and nitrites suggest

Answer 8

infection

Question 9

AKI urinalysis: protein and blood suggest

Answer 9

acute nephritis

Question 10

AKI urinalysis: glucose

Answer 10

diabetes

Question 11

Preventing AKI

Answer 11

avoiding nephrotoxic meds where possible

insure adequate fluid input in unwell patients (IV if not taking orally)

Question 12

managing AKI

Answer 12

IV fluid rehydration in pre-renal
stop nephrotoxicmeds
releive pbstriction if port-renal

Question 13

AKI complications

Answer 13

hyperkalaemia
fluid overload
heart failure 
pulmonary oedema 
metabolic acidosis
uraemia --> encephalopathy, pericarditis

Question 14

AKI stage 1

Answer 14

creatinine 1.5-1.9x baseline or 25micromol/l increase

UO <0.5 6-12hrs

Question 15

AKI stage 2

Answer 15

creatinine 2-2/9x baseline

UO < 0.5 for 12+hrs

Question 16

AKI stage 3

Answer 16

creatinine 3x baseline or inc to 354+ micromol/l

initiation RRT

UO <0.3ml for 24+hrs or anuria for 12+hrs

Question 17

ECG changes in hyperkalaemia

Answer 17

peaked T waves
P wave wide and flat
prolonged PR interval 
P waves eventually dissapesr
prolonged QRS

Question 18

hyperkalaemia management

Answer 18

stabilise myocardium - calcium gluconate
shift K+ into cells - salbutamol, insulin-dextrose
remove - diuresis, dialysis, anion exchange resins