Oliguria

Question 1

Define oliguria.

Answer 1

Oliguria is defined as urine output < 0.5 mL/kg/hr (adult) or < 1mL/kg/hr (neonates)

Question 2

What are the clinical features of prerenal azotemia?

Answer 2

Thirst
Hypotension
Tachycardia

Question 3

What drugs may be in the recent history of someone with renal azotemia?

Answer 3

Recent use of:
Contrast dye
Aminoglycoside antibiotics
NSAIDs

Question 4

What are the clinical features of postrenal azotemia?

Answer 4

Bladder distension

Urge to void

Question 5

What is the differential diagnosis for oliguria?

Answer 5

1. Prerenal - absolute or relative decrease in renal perfusion (bleeding, hypovolemia, CHF)
2. Renal - glomerular, tubular, vascular, interstitial (acute tubular necrosis)
3. Postrenal - obstruction (blocked catheter, prostatic hypertrophy)

Question 6

What is the management of oliguria?

Answer 6

1. Avoid further renal insults
   - maintain euvolemia (CVP 10 - 15 mm Hg)
   - maintain adequate renal perfusion (MAP > 65 mm Hg)
   - avoid nephrotoxins
2. Intravascular volume assessment may require invasive monitors (CVP, PAWP, TEE)
3. Identify and treat underlying cause
4. May require hemodialysis