Acute Kidney Injury (AKI)

Question 1

Acute kidney injury is diagnosed by measuring?

Answer 1

Serum Creatinine
* Rise of more than 25 micromol/L in 48 hours
* Rise of more than 50% in 7 days
* Urine output of less than 0.5ml/kg/hour over at least 6 hours

Question 2

Pre renal causes of AKI?

Answer 2

Most common
Due to insufficient blood supply (hypoperfusion) to kidneys which reduces the filtration of blood

Due to:
* Dehydration
* Shock (e.g. sepsis or acute blood loss)
* Heart failure

Question 3

Renal causes of AKI?

Answer 3

Caused by intrinisc disease in the kidney
* Acute tubular ncrosis
* Glomerulonephritis
* Acute interstitial nephritis
* Haemolytic uraemic syndrome
* Rhabdomyolysis

Question 4

Post-renal causes of AKI?

Answer 4

Involve the obstruction of outflow of urine from the kidney= back pressure and reduced kidney function= obstructive uropathy

Caused by:
* Kideny stones
* tumours
* Strictures of the yreters or urethra
* Benign prostatic hyperplasia
* Neurogenic bladder

Question 5

What is acute tubular necrosis? Causes and how is it confirmed?

Answer 5

Damage and death of the epithelial cells of the renal tubules

Damage occurs due to:
* Ischaemia due to hypoperfusion
* Nephrotoxins e.g. gentamicin, cisplatin or radiocontrast

Muddy brown casts on urinalysis confirm it.

Question 6

Investigations for AKI?

Answer 6

Urinalysis:
* Proteins and blood- acute nephritis
* Leucocytes and nitrites- infection
* Glucose- diabetes

Ultrasound of urinay tract assess for obstruction when post renal cause is suspected