Polyuria

Background

• Excessive urine volume
  • Distinguish from urinary frequency, which may not produce high volumes of urine

Clinical Features

• 3 L/day of urine in adults and 2 L/m2 in children

Differential Diagnosis

Polyuria

• Osmotic diuresis
  • Hyperglycemia
  • Mannitol
• Drugs: diuretics, caffeine, acetazolamide, lithium
• Hypercalcemia
• Hypokalemia
• Diabetes insipidus
• Cushing's syndrome, primary hyperaldosteronism
• Inability to concentrate urine (e.g. chronic pyelonephritis, sickle cell disease, amyloidosis
• Post-obstructive diuresis
• Early renal failure
• High fluid intake
  • Excess IVF
  • Psychogenic polydipsia

Evaluation

• Evaluate for dehydration
• BMP
• UA
• Additional workup depending on history
• Consider:
  • Urine osmolality, electrolytes
  • Serum osmolality
  • Serum ADH
  • Renal imaging

Management

• Correct electrolyte abnormalities, dehydration
• Treat underlying pathology if known

Disposition

• Dependant on presentation/severity