Acute Kidney Injury

Question 1

What is acute kidney injury?

Answer 1

Decrease in kidney function due to sudden damage, It can range from mild damage to kidney failure.

Question 2

What are the 3 categories of AKI?

Answer 2

Pre-renal - caused by a reduction in perfusion
Renal - damage to kidney
Post-renal - obstruction

Question 3

What are some of the causes of Pre Renal AKI?

Answer 3

VASCULAR - hypovolaemia (blood loss, fluid loss), kidney artery stenosis, emboli, heart failure, cardiac shock (tamponade)
INFECTION: septic shock (systemic vasodilation)
IATROGENIC - drugs NSAIDS (Pre glomerular vasocontriction)

Question 4

What is seen in a urine analysis of a patient with a pre renal cause of AKI?

Answer 4

Urine normal however has hyaline casts - aggregations of protein seen in concentrated urine

Question 5

What are some causes of renal AKI?

Answer 5

IATROGENIC - drugs - NSAIDs, ACE inhibitors, gentamicin, metformin
VASCULAR - vasculitis, thrombosis, severe acute ischaemia
AUTOIMMUNE- glomerulonephritis
INFECTION - interstital nephritis, acute pylonephritis
Acute Tubular Necrosis

Question 6

What are some examples of nephrotoxins?

Answer 6

Damage the epithelial cells lining the tubules causing cell death and shedding into the lumen.
Endogenous - myoglobin, urate, bilirubin
Exogenous - X-ray contrast, ACEi, NSAIDs, gentamicin, aminoglycosides, weed killer, antifreeze

Question 7

What are the causes of a post renal AKI?

Answer 7

Obstruction can occur at 3 sites

1. Ureters (bilaterally)
2. Entry into bladder
3. Urethra

Question 8

What are some common symptoms of renal calculi?

Answer 8

Haematuria and loin to groin pain (due to peristalsis of the ureters moving the calculi)

Question 9

What is found in urinanalysis of a patient with glomerulonephritis?

Answer 9

Proteinuria, Haematuria and RBC casts

Question 10

What is found in microscopy of urine from a patient with ATN?

Answer 10

Muddy brown casts

Question 11

What would blood test results show in a patient with AKI?

Answer 11

Increased Urea and Creatinine

Question 12

Which conditions can cause secondary glomerulonepritis?

Answer 12

SLE and vasculitis

involved as part of a systemic process

Question 13

What is the treatment for a pre renal AKI?

Answer 13

Hypovolaemia –> fluid
heart failure –> diuretics
Correct underlying cause

Question 14

What is the treatment for a post renal AKI?

Answer 14

Urological intervention to reestablish urine flow

Question 15

What is the treatment for a ATN?

Answer 15

Maintaining good kidney perfusion and avoid nephrotoxins

Question 16

What is an indication for dialysis?

Answer 16

When the kidneys can no longer excrete water, salts and potassium.

Question 17

What are some complications of AKI?

Answer 17

Hyperkalaemia
Metabolic Acidosis
pulmonary oedema - caused by giving extra IV fluids to patients who are oliguric or anuric

Question 18

What can be seen on an ECG in hyperkalaemia?

Answer 18

Tall tented T waves
Small/absent P waves
Increased PR interval
Wide QRS complex