Polydipsia is possible to rule out psychogenic polydipsia or habit polydipsia. Polydipsia is a symptom (evidence of a disease state), not a disease in itself. As it is often accompanied by polyuria, investigations directed at diagnosing diabetes insipidus and diabetes mellitus can be useful. Blood serum tests can also provide useful information about the osmolality of the body's extracellular fluids. A decrease in osmolality caused by excess water intake will decrease the serum concentration of red blood cells, blood urea nitrogen (BUN), and sodium. Polydipsia Polydipsia is excessive thirst or excess drinking. The word derives from the Greek () "very thirsty",
Polydipsia decreased blood volume (as occurs during major hemorrhage), and other conditions that create a water deficit. This is usually a result of osmotic diuresis. Diabetes insipidus ("tasteless" diabetes, as opposed to diabetes mellitus) can also cause polydipsia. Polydipsia is also a symptom of anticholinergic poisoning. Zinc is also known to reduce symptoms of polydipsia by causing the body to absorb fluids more efficiently (reduction of diarrhea, induces constipation) and it causes the body to retain more sodium; thus a zinc deficiency can be a possible cause. The combination of polydipsia and (nocturnal) polyuria is also seen in (primary) hyperaldosteronism (which