oliguria

Introduction

Urine output < 400 mL/day or < 20 mL/hour in adults, < 240 mL/day in children, & < 15-20 mL/kg/day in neonates. Urine flows less than this are insufficient to excrete the daily osmolar load.

Etiology

• pre-renal
  • hypovolemia
    • hemorrhage
    • dehydration
      • gastrointestinal losses
      • renal losses (diuretics)
  • decreased effective blood volume
    • vasodilation
      • pharmacologic agents
      • sepsis
      • anaphylaxis
    • sequestration of extracellular fluid (3rd spacing)
      • burns
      • abdominal surgery
      • peritonitis
      • pancreatitis
      • congestive heart failure (CHF)
      • cardiogenic shock
      • hepatorenal syndrome
      • hypoalbuminemia
• renal
  • acute tubular necrosis (ATN)
    • ischemia
      • hypotension
      • sepsis
    • nephrotoxin
      • aminoglycosides radiographic contrast agent
    • rhabdomyolysis
    • eclampsia
  • vascular disease
    • renal vein thrombosis
    • renal vasculitis
    • malignant hypertension
  • bilateral renal cortical necrosis
  • end-stage renal disease (ESRD)
  • acute glomerulonephritis
  • hemolytic-uremic syndrome (HUS)
  • acute interstitial nephritis (AIN)
  • hypercalcemia
  • urine paraproteins
    • multiple myeloma
    • Waldenstrom's macroglobulinemia
    • amyloidosis
  • urinary crystals
• post-renal (rare in children)
  • bilateral ureteral obstruction
    • external compression
      • retroperitoneal fibrosis
      • tumor
      • lymph nodes
    • intrinsic occlusion
      • urinary calculus
      • tumor
  • bladder outlet obstruction
    • neurogenic bladder
    • urinary calculus
    • tumor
    • posterior urethral valves - newborn males
  • urethral obstruction
    • prostatic enlargement
    • stricture
    • trauma
  • congenital malformation of kidney
    • children

Laboratory

• urine output
• urinalysis
  • protein by dipstick
  • microscopy
    • tubular epithelial cells
    • RBC
    • RBC casts
    • WBC casts
• urinary indices*
• serum chemistries
  • urea nitrogen
  • creatinine
• complete blood count (CBC)
• renal ultrasound
• cystoscopy & retrograde pyelogram
• renal flow scan *Indices of oliguria

index	prerenal	ATN*
urine osmolality (mOsm/L)	> 500	< 350
urine/plasma creatinine	> 40	< 20
BUN/creatinine (plasma)	> 20	< 15
FENA#	< 1%	> 3%

* acute tubular necrosis

# fractional excretion of sodium

Management

• catheterize bladder - relieve obstruction
• optimize arterial blood volume & cardiac status
  • fluid challenge with saline unless in CHF
  • restrict salt & water intake if in CHF
• discontinue nephrotoxic agents
• maintain electrolyte balance
• maintain acid-base status
• treat hypertension
• treat hypotension
• monitor input & output
• maintain urine output after hemodynamics & arterial blood volume is maximized
  • loop diuretics
  • low-dose dopamine
• hemodialysis

More general terms

• sign/symptom

More specific terms

• anuria

Additional terms

• acute renal failure (ARF)