Acute Kidney Injury

Question 1

What defines AKI?

Answer 1

Sudden deterioration of renal function with

Increases in serum creatinine (over 1.5 X baseline) and/or low urine volume

Question 2

What are common physiological features of an acute kidney injury?

Answer 2

1. Decreased GFR
2. Rapid increase in serum urea and creatinine
3. decreased urine output
   * and usually serious illness

Question 3

What is the main problem in prerenal AKI? What are 4 main causes?

Answer 3

Decreased perfusion

Hypovolemia, cardiac failure, systemic vasodilation, anaphylaxis, cirrhosis, impaired renal autoregulation

Question 4

Four drugs that could impair renal autoregulation

Answer 4

NSAIDS, ACE inhibitors, angiotensin II agonists, cyclosporine (activates RAAS)

Question 5

What does a post-renal AKI indicate?

Answer 5

Obstructed urinary flow

*Can occur at ureters, bladder or urethra

Question 6

Where can post-renal obstructions be coming from?

Answer 6

Within the lumen: stones, clots, etc

Within wall: congenital, ureteric stricture

External pressure: prostatic hypertrophy, malignancy, diverticulitis, pancreas, etc

Question 7

What are some typical features of a post-renal AKI?

Answer 7

Nausea and lethargy

Decreased urine output, enlarged bladder, fluid overload: edema, orthopnea

Electrolyte abnormality, acid-base disturbance

Platelet dysfunction (uremic toxins in blood) -> GIT bleeding

Question 8

What is the cause of intrinsic AKI? Name 3 examples:

Answer 8

Direct injury to the kidney

1. Acute glomerulonephritis
2. Tubular damage
3. Vascular damage

Question 9

What are 3 things that could cause tubular damage?

Answer 9

Ischemia, sepsis, nephrotoxins

Question 10

When is acute tubular necrosis likely to have occured?

Answer 10

Nephrotoxins + reduced perfusion

*Cause of intrinsic AKI

Question 11

Name 3 examples of nephrotoxins

Answer 11

1. Aminoglycosides (renal vasoconstriction)
2. Bacterial endotoxins
3. Tumour lysis syndrome

Question 12

How would you manage AKI?

Answer 12

1. ABCDE assessment
2. Check serum K+ level
3. Fix patient’s volume status
4. Antibiotics if there’s sepsis
5. Take them off any nephrotoxic drugs

Question 13

What could you look for on a blood test for AKI?

Answer 13

1. complement: C3 and C4
2. autoantibodies: ANA and ANCA
   3, Creatine kinase and urea
3. protein

Question 14

What does the AEIOU acronym stand and check for?

Answer 14

Indications for renal replacement therapy:

Acidemia, electrolytes (uncontrolled hyperkalemia), Ingestion of toxins, oedema, uremia

Question 15

What are 2 types of blood tests relevant to AKI?

Answer 15

1. Serum electrophoresis: measures specific proteins in blood
2. Serum free light chain test