Increased Thirst (Polydipsia) in Dogs
Key takeaways
Increased thirst, or polydipsia, is a common symptom of many conditions in dogs.
- Pet parents may conclude a dog is excessively thirsty based on subjective observations, like suddenly finding the water bowl is constantly empty, or from objective measurements
- Individual variations are expected, but daily water consumption in excess of 100 mL per kg of body weight is considered excessive
- Thirst after exercise or exertion is normal
- A dog that is persistently thirstier than usual may have serious underlying conditions such as kidney disease, pyometra, or diabetes mellitus
- Conditions that cause excessive urination often lead to excessive drinking as a secondary symptom
- Sudden excessive thirst might indicate poisoning
- The typical diagnostic approach for a dog showing excessive thirst begins with a physical examination, blood work, and urinalysis
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A closer look: Increased Thirst (Polydipsia) in Dogs
Increased thirst is a common symptom of multiple conditions. Persistent or sudden increased thirst with no known cause such as exercise, or along with other symptoms of illness, is cause for concern and warrants medical attention. Increased thirst indicates an EMERGENCY if observed with certain additional symptoms.
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Possible causes
Gradual but noticeable increase in thirst in dogs is commonly associated with a number of conditions.
Sudden increased thirst may be one of the symptoms shown by dogs after ingesting a toxin.
Increased thirst is a side-effect of some medications including but not limited to:
- Corticosteroids (e.g. prednisone/prednisolone)
- Diuretics
- Seizure medication
Some cases of excessive thirst are due to psychogenic polydipsia: an exceedingly rare behavioral disorder in which the dog drinks excessively with no physiologic cause. This is diagnosed only when all other potential causes are ruled out.
Risk factors
Increased thirst can be characterized as compensatory, occurring secondary to excessive urination (polyuria).
A sudden onset of polydipsia combined with other symptoms is more likely to be an emergency.
Changes in thirst can indicate a worsening of an underlying condition. If a dog showing changes in thirst has been previously diagnosed with chronic conditions such as kidney failure, liver disease, or diabetes, seek urgent veterinary care. If a dog shows increased thirst but no other notable symptoms, it is best to seek non-emergency veterinary care to rule out serious conditions.
Testing and diagnosis
A dog with increased thirst usually requires the following diagnostics to determine the best course of action:
- Physical examination
- Blood work
- Urinalysis Diagnostic imaging
- Water deprivation test: this test will only be suggested if other diagnostics are inconclusive, as it challenges the kidneys and bears a degree of risk to the impacted animal
- Therapeutic trial with desmopressin (used to treat diabetes insipidus)
Treatment varies depending on the underlying cause.
Similar symptoms
- Normal thirst
- Nausea
- Oral irritation, as occurs after eating or chewing on something that stings
