Acute Kidney Injury

Question 0

What are the three categories of AKI?

Answer 0

Pre renal failure
Intrinsic renal failure
Post renal failure

Question 1

What is AKI?

Answer 1

An abrupt decline in GFR over a period of days to weeks.

AKI is a medical emergency and delayed treatment will lead to irreversible renal failure.

Question 2

What are the causes of pre renal failure?

Answer 2

Reduction in renal perfusion

• reduced effective ECF volume
• impaired renal autoregulation

Question 3

What are the causes of intrinsic renal failure?

Answer 3

• Acute tubular necrosis
• Glomerular and arteriolar disease
• Acute tubulo-interstitial nephritis

Question 4

List some endogenous and exogenous nephrotoxins.

Answer 4

Endogenous: myoglobin, urate, bilirubin
Exogenous: X-ray contrast, drugs e.g. Gentamicin, ACEi, NSAIDs, Angiotensin receptor blockers

Question 5

What are the causes of post-renal failure?

Answer 5

Obstruction with continuous urine production causing raised intraluminal pressure, hydronephrosis (dilatation of renal pelvis), decreased renal function.

• Obstruction within the lumen
• Obstruction within the wall
• Pressure from outside the lumen

Question 6

How do you treat pre-renal failure?

Answer 6

Volume correction.

• In hypovolaemia administer fluids
• In cardiac failure give duiretic

Question 7

How do you treat post-renal failure?

Answer 7

Urological intervention to re-establish flow of urine.

Question 8

How do you treat acute tubular necrosis?

Answer 8

Supportive treatment to maintain good kidney perfusion. Avoid nephrotoxins.

Question 9

List some causes of reduced effective ECF volume.

Answer 9

• hypovolaemia (blood loss, fluid loss),
• cardiac failure (LV dysfunction, tamponade),
• systemic vasodilation (sepsis, cirrhosis, anaphylaxis).

Question 10

List some causes of impaired renal autoregulation.

Answer 10

• preglomerular vasoconstriction (sepsis, hypercalcaemia, NSAIDs)
• postglomerular vasodilation (ACEi, AT2 receptor antagonist)

Question 11

List some causes of acute tubular necrosis.

Answer 11

• severe acute ischaemia

- nephrotoxins

Question 12

List some causes of glomerular and arteriolar disease.

Answer 12

• Acute glomerulonephritis
• haemolytic uraemic syndrome
• malignant hypertension
• pre eclampsia

Question 13

List some causes of acute tubulo-interstitial nephritis.

Answer 13

• infection

- toxin induced

Question 14

List some cause of obstruction within the lumen.

Answer 14

• calculi
• blood clot
• papillary necrosis
• tumour (renal pelvis, ureter, bladder)

Question 15

List some causes of obstruction in the wall.

Answer 15

• congenital causes (pelviureteric muscular dysfunction, megaureter, neurogenic bladder)
• ureteric stricture (post-TB).

❄️ Usually a cause of CKD❄️

Question 16

List some causes of pressure from outside the lumen.

Answer 16

• prostatic hypertrophy
• tumours
• AAA
• accidental ligation of ureter