Acute Kidney Injury

Question 1

Define Acute Kidney Injury

Answer 1

An abrupt (<48 hrs) reduction in kidney function defined as:

• an absolute increase in serum creatinine by more than 26.4umol/l
• or increase in creatinine by > 50%
• or reduction in urinary output (<0.5 ml/kg/ hr over six hours)

Question 2

What are the three categories of acute kidney injury?

Answer 2

Pre renal
Renal
Post renal

Question 3

Pre renal causes are due to

Answer 3

impaired renal perfusion

Question 4

List some pre renal causes of AKI?

Answer 4

Hypovolaemia due to haemorrhage or volume depletion in diarrhoea and vomiting or burns
Hypotension in shock (cardiogenic, septic or anaphylactic)
Renal hypo perfusion due to NSAIDs, ACEi or hepatorenal syndrome

Question 5

How can NSAIDs cause acute kidney injury?

Answer 5

NSAIDs inhibit the normal prostaglandin induced vasodilation of the renal arterioles and if someone has volume depletion this can then cause reduced perfusion enough to cause AKI

Question 6

Prostaglandins cause _____

Answer 6

vasodilation of the renal arterioles

Question 7

How can ACEi cause AKI?

Answer 7

Ace inhibitors reduce angiotensin 2 which usually causes vasoconstriction of the efferent arteriole, dilation of the efferent arteriole reduces the GFR which can be enough to cause AKI

Question 8

What is hepatorenal syndrome?

Answer 8

Syndrome of renal failure in patients with a cirrhotic liver

Question 9

Untreated pre-renal AKI leads to _____

Answer 9

Acute tubular necrosis

Question 10

Treatment of pre renal AKI?

Answer 10

Assess hydration by measuring BP, HR and UO. Assess for JVP, cap refill, oedema and PO. Fluid challenge for hypovolaemia using crystalloid 0.9% NaCl or colloid (gelofusin). Bolus of fluid, reassess, repeat if given more than 1000ml and still no improvement seek help.

Question 11

Renal causes are due to ______

Answer 11

Inflammation or damage to the kidney cells

Question 12

List some renal causes of AKI?

Answer 12

Vascular- vasculitis or renovascular disease
Glomerular- glomerulonephritis
Interstitial Nephritis- caused by drugs, infections (TB), systemic illnesses e.g. TB
Tubular injury- ischaemia, drugs (gentamicin), contrast and rhabdomyolysis

Question 13

Treatment of renal AKI?

Answer 13

Fluid resuscitation, treat underlying cause, stop any nephrotoxic drugs, dialysis if anuric and uraemia.

Question 14

Post renal AKI is due to ______

Answer 14

Obstruction

Question 15

What happens in post renal AKI?

Answer 15

Obstruction of urine flow leads to back pressure (hydronephrosis- swelling of kidney due to failure or urine to drain) and thus loss of concentrating ability

Question 16

Causes of post renal AKI?

Answer 16

stones, cancers, strictures, intrinsic pressure, prostatic disease

Question 17

Treatment of post renal AKI?

Answer 17

Relive obstruction

Question 18

4 urgent indication for haemodialysis in AKI?

Answer 18

Canbe remembered using AEIOU

Acidosis
Electrolyte disturbance that is severe/ unresponsive
Ingestion of toxins/ overdose
Overload/ pulmonary oedema
Uraemia

Question 19

What is a life threatening complication of AKI?

Answer 19

Hyperkalaemia as associated with cardiac arrhythmias

Question 20

What is an early sign of hyperkalaemia on ECG?

Answer 20

Tall tented T waves

Question 21

Hyperkalaemia is defined as

Answer 21

potassium > 5.5 (life threatening > 6.5)

Question 22

Treatment of hyperkalaemia?

Answer 22

Cardiac monitor, 10% calcium gluconate, insulin and salbutamol (to move K+ back into cells), calcium resonium (prevent GI absorption)

Question 23

Describe sick day rules to prevent AKIs?

Answer 23

If fever, shakes and chills or diarrhoea or vomiting for more than 24 hrs stop taking
ACEi or ARBs
NSAIDs
Diuretics
Metformin
SGLT2i

Restart tablets only once feeling well and have been eating and drinking normally for 24hrs

Question 24

Describe investigations for AKI?

Answer 24

Measure haemoglobin, bicarbonate, calcium, phosphate and if suspect sepsis CRP, lactate and cultures
Urine dipstick in everyone. If blood or protein is present request immunology > ANA, ANCA, Ig, C3/4. Urine protein: creatinine ratio.
Myeloma screen in > 50 yo with anaemia and hypercalcaemia
US in obstruction

Question 25

6 groups of people with AKI to refer?

Answer 25

All AKI stage 3 or CKD stage 4/5
Transplant patients
K+ > 6.5 mol/ L
Suspicion of intrinsic renal cause > blood or protein on dipstick
Persistent pulmonary oedema
Oliguria or deterioration despite treatment

Question 26

Low complement levels in AKI may suggest?

Answer 26

Lupus nephritis

Question 27

Someone with AKI and haemoptysis?

Answer 27

Goodpastures syndrome

Question 28

Someone with AKI who has had a recent skin or throat infection?

Answer 28

Post infectious glomerulonephritis

Question 29

Man with an AKI increased urinary frequency, dribbling, hesitancy?

Answer 29

Prostatic obstruction

Question 30

Someone with AKI and has had muscle pain and swelling after exercise?

Answer 30

Rhabdomyolysis (myoglobin from muscle break down breaks down into substances toxic to kidney cells)

Question 31

ANA or Anti dsDNA?

Answer 31

SLE

Question 32

Anti glomerular basement membrane antibodies?

Answer 32

Goodpastures syndrome

Question 33

ANCA?

Answer 33

Vasculitis

Question 34

People with acute kidney injury should be monitored for the development of progression of CKD for _____

Answer 34

at least 2–3years after acute kidney injury, even if serum creatinine has returned to baseline

Question 35

Sine wave appearance on ECG?

Answer 35

Severe hyperkalaemia

Question 36

Treatment of interstitial nephritis caused by drugs?

Answer 36

Stop the drug

May give prednisolone