Polydipsia describes a symptom in which the affected person consumes large volume of water and other fluids due to excessive thirst. It may arise as a result of Polyuria, the passing of large volumes of urine.
Polydipsia is a symptom, not a disease (cause). To diagnose the cause of polydipsia a fluid deprivation test is used, which may require a patient to abstain from water, and for blood and urine tests to be undertaken. Additional blood work may be required to test for the presence of diuretics, such as caffeine, or recreational drugs. Finally neurological testing may be required to determine if there has been damage to the hypothalamus.