polyuria refers to increased urine volume, not just going more often; many patients with frequency alone pass only small amounts and do not meet criteria for polyuria. Adults with polyuria may produce up to 10-15 liters of urine per day, often accompanied by polydipsia (excessive thirst) and nocturia (waking at night to void). Common causes include uncontrolled diabetes mellitus (osmotic diuresis), diabetes insipidus (ADH deficiency or resistance), primary polydipsia, use of diuretics, and excessive fluid intake.