Polyuria

Definition

Polyuria is abnormally large urine volume (greater than 3,000 mL/day in adults). It may indicate osmotic diuresis, impaired renal concentrating ability, or excessive fluid intake.

Causes

• Diabetes mellitus (osmotic diuresis from glucose)
• Diabetes insipidus (decreased ADH action)
• Diuretic use
• Hypercalcemia
• Excessive fluid intake
• Post-obstructive diuresis
• Chronic renal failure

Assessment

24-hour urine collection, urine specific gravity (low in DI, high in DM), serum sodium, glucose, calcium, osmolality.

Nursing Interventions

Monitor I&O, daily weights, vital signs, electrolytes. Replace fluids as needed, for diabetes: glucose management. For DI: desmopressin. Safety: fall prevention from frequent toileting; dehydration risk.

NCLEX Relevance

3 P's of diabetes, such as dI presents with dilute urine, DM with glucose in urine.