Acute Kidney Injury

Question 1

What are the causes of acute kindey injury?

Answer 1

1. pre-renal(60% of the cases)
2. intra-renal (35% of the cases)
3. post-renal (5% of the cases)

Question 2

What are the causes of prerenal acute kidney injury?

Answer 2

• decreased blood flow to the kidneys
  1. hypovolaemia( burns, diuretics)
  2. hypotension(dehydration)
  3. renal vasoconstriction/stenosis
  4. drugs: NSAIDS which cause constriction of the afferent arteriole and ACE inhibitors which vasoconstrict the efferent arteriole

Question 3

What is the normal ratio of urea:creatinine?

Answer 3

5-20:1

Question 4

What are the causes of intrarenal kidney injury?

Answer 4

• direct kidney damage
  1. acute tubular necrosis caused by ischaemia, drugs, nephrotoxins, infections
  2. glomerulonephrtis
  3. tubulointerstitial nephritis(drug induced, infectious, immulogical)
  4. Vascular- vasculitis, thromboic thromocytopenia purpura

Question 5

what are the post-renal causes of acute kidny injury?

Answer 5

• bilateral obstruction of urine from renal pelvis to ureter
  1. conenital malformations
  2. acquired
• benign prostatic hyperplasia
• tumours
• stones
  3. neurogenic bladder
• multiple sclerosis
• peripheral neuropathy

Question 6

What are the 4 phases of acute kidney injury? Not everyone will go through these phases

Answer 6

1. Initiating event-symptoms of the underlying illness causing the AKI will be present
2. Oliguric phase- reduces urine production and increased retention of creatinine and urea leading to oedema (pulmonary oedema, hyperkalamia, metabolic acidosis
3. Polyuric phase/diuretic phase
4. Recovery phase

Question 7

What are the clinical features of acute kidney injury?

Answer 7

1. Oliguria
2. Signs of volume depletion- hypotension, tachycardia, reduces skin turgor
3. Signs of fluid overload- pulmonary oedema, peripheral oedema, hypertension
4. Signs of uremia- anorexia, nausea, pericarditis

Question 8

What is the treatment of AKI?

Answer 8

1. Treat the underlying cause
2. Stop nephrotoxic drug
3. Monitor changes in pH, water, electrolyte balance
4. Perform dialysis