Quantitative changes of urine

One normally produces 500 - 2500 mL of urine per day. In case of pathology, the amount may be increased or decreased.

Polyuria refers to pathologically increased amount of urine (> 2500 mL/day) or > 50 mL per kg of bodyweight per hour. It's a relatively rare finding.

Oliguria refers to decreased amount of urine (100 - 500 mL/day) or < 20 mL/hour or < 0.5 mL per kg of bodyweight per hour.

Anuria refers to having < 100 mL of urine during a day.

Causes

• Polyuria
  • Diabetes insipidus
  • Diabetes mellitus
  • Diuretics
  • Primary polydipsia (psychogenic)
• Oliguria
  • Due to acute kidney injury
  • Prerenal causes
    • Dehydration
    • Heart failure
    • Renal artery stenosis
  • Intrarenal causes
    • Acute tubular necrosis
    • Acute or chronic glomerulonephritis
    • Acute interstitial nephritis
  • Postrenal causes
    • Obstruction
• Anuria
  • Generally same as for anuria, but more severe