AKI

Question 1

How is AKI diagnosed?

Answer 1

any ONE of:

• rise in creatinine of >26 mmol/L above the pt’s baseline (whether this is normal or not) in 48 hrs (even if the rise means that the creatinine is still in the normal range, this is AKI
• rise in creatinine >50% of the best figure in the last 6 months
• urine output of <0.5ml/kg/hr for >6 consecutive hours (about 30ml for 60kg in 1 hr)

Question 2

what categories can we divide the causes of AKI into?

Answer 2

pre-renal
renal
post-renal

Question 3

how do we assess pts with AKI?

Answer 3

• history - ask about associated signs of the underlying cause eg cough and fever with sepsis, SOB, chest pain and palpitations for heart failure, rash, arthralgia and flu for GN, signs of cancer
• physical examination - head to toe, chest exam for infection, dehydration
• differential diagnoses
• investigations and management

Question 4

what is a very important medical emergency associated with AKI?

Answer 4

hyperkalaemia

Question 5

what ECG changes are seen with hyperkalaemia?

Answer 5

peaked T waves

small/indiscernible P waves

Question 6

How is hyperkalaemia managed?

Answer 6

need to identify risk factors and common causes of the hyperkalaemia
do necessary investigations
insulin and dextrose
calcium gluconate - membrane stabiliser that protects the heart
IV fluid
salbutamol nebuliser
calcium resonium (last resort K+ binders)

Question 7

What are the risk factors for AKI?

Answer 7

age
co-morbidities - DM, heart failure, hypertension
reasons for admission- dehydration and sepsis
drugs

Question 8

what should be done before referral to a specialist nephrologist ie initial management of AKI?

Answer 8

history
examination
blood tests - FBC, U+E, calcium, phosphate, potassium
ultrasound KUB
IV fluid
urine dipstick
drug review - adjust dose, nephrotoxic drugs
fluid balance - intake and output
current volume status - dry (dehydration)or wet (pulmonary oedema)

Question 9

What investigations are done for AKI?

Answer 9

urinalysis - check for blood and protein 
blood tests:
• U+E
• calcium
• phosphate
• albumin
• ALP
• FBC - for anaemia (EPO affected)
ultrasound KUB to make sure no obstruction 
urine microscopy and culture

Question 10

when should a pt with AKI be referred to a nephrologist?

Answer 10

• AFTER treating the urgent causes and initial management
• refractory hyperkalaemia
• refractory pulmonary oedema
• severe acidosis
• symptomatic uraemia
• Urea > 40 mmol/L +/- signs of uraemia
• No obvious cause
• Creatinine > 300 or rising > 50 micromol/L per day

Question 11

What are the complications of AKI?

Answer 11

hyperkalaemia
pulmonary oedema
uraemia - uraemic pericarditis, uraemic encephalitis, pruitus
acidaemia

Question 12

What are the indications for dialysis?

Answer 12

Refractory pulmonary oedema
Persistent hyperkalaemia
Severe metabolic acidosis
Uraemic encephalopathy or pericarditis
Drug overdose BLAST

Question 13

An overdose of which drugs would be an indication for dialysis?

Answer 13

Barbiturate
Lithium
Alcohol-ethylene glycol
Salicylate
Theophylline

Question 14

What are the pre-renal causes of AKI?

Answer 14

anything that causes reduced blood flow to the kidneys:

• major haemmorhage
• vomiting
• diarrhoea
• severe burns
• distributive shock
• congestive heart failure
• hypotension
• sepsis
• renal artery stenosis
• dehydration
• any cause of hypovolaemia

Question 15

what are the intrarenal causes of AKI?

Answer 15

acute tubular necrosis
glomerulonephritis
acute interstitial nephritis

Question 16

what are the post-renal causes of AKI?

Answer 16

• compression of the ureters by intra -abdominal tumours
• compression of the urethra by BPH
• kidney stones
• bladder cancer
  ie luminal, mural and extrinsic compression causes