Polydipsia in Cats: Diagnosing the Cause of Excessive Thirst

Excessive thirst (polydipsia) in cats is a clinical sign of several serious underlying conditions. Accurate diagnosis and prompt treatment prevent welfare deterioration.

Key Facts

Polydipsia is defined as water intake exceeding 100ml per kg body weight per day
Common causes include chronic kidney disease, diabetes mellitus, hyperthyroidism, and hypercalcaemia
Psychogenic polydipsia (stress-induced) is less common in cats than in dogs but occurs in anxious individuals
A minimum database including biochemistry, haematology, and urinalysis allows differentiation of common causes

Welfare Considerations

The underlying causes of polydipsia each carry significant welfare implications — untreated diabetes causes ketoacidosis and suffering; chronic kidney disease causes uraemia; hyperthyroidism causes hypertension and cardiac enlargement. Early identification of the cause through a minimum diagnostic database allows targeted treatment before organ damage becomes irreversible. Home monitoring of water intake provides objective data for veterinary assessment — water bowls can be measured daily to quantify intake.

What You Can Do

Monitor your cat's water intake for any sustained increase and report it to your vet promptly
Provide water in multiple locations and bowl types to ensure accurate intake monitoring is possible
Request a minimum diagnostic database (bloods, urinalysis) rather than empirical treatment when polydipsia is reported
Implement treatment promptly once a cause is identified — early intervention prevents progression to organ failure