Polydipsia and Polyuria in Dogs
Polydipsia refers to an increased level of thirst in dogs, while polyuria refers to an abnormally high urine production. While serious medical consequences are rare, your pet should be evaluated to ensure that these conditions are not symptoms of a more serious underlying medical condition. Your veterinarian will want to either confirm or rule out renal failure, or hepatic diseases.
Polyuria and polydipsia can affect both dogs and cats, and can be brought on by a variety of factors. If you would like to learn more about how these diseases affect cats, please visit this page in the PetMD health library.
Symptoms
The most common symptoms of these medical conditions are an increase in urination, and drinking much more water than usual. There are generally no other behavioral changes.
Causes
The primary causes of polydipsia and polyuria include congenital abnormalities, and those associated with renal failure. Congenital diseases can include diabetes, a decrease in steroid production by the adrenal glands, and some rare psychological disorders. Kidney diseases, meanwhil, can be congenitally based, or can be linked to tumors, increased steroid production, increased thyroid hormone levels, and electrolyte or hormonal disorders.
Other potential factors behind polydipsia and polyuria are low protein diets, medications that are prescribed for removing excess fluid from the body (diuretics), and age. The younger and more active a dog is, the more likely it is that it will have intermittent increases in thirst and urination.
Diagnosis
Your veterinarian will examine your dog to determine the true levels of thirst and urination by measuring water intake and urination output. A baseline of normal fluid levels (hydration) and normal urination will be established for comparison, and an evaluation will be performed to ensure that the increased thirst and urination are not signs of a more serious medical condition.
Standard tests will include a complete blood count (CBC), a urinalysis, and X-ray imaging to rule out or confirm any issues with the kidney (renal) system, the adrenal system, and the reproductive systems.
Any other symptoms accompanying the increased levels of thirst or urination, even when appearing unrelated, will be taken into consideration during the final diagnosis.
Treatment
Treatment will most likely be on an outpatient basis. The primary concern is that renal or hepatic failure can be causing increased water consumption or increased urination. If both of these concerns have been ruled out, and there are no other serious medical conditions associated with either of these conditions, no treatment or behavior modification will be necessary.
Your doctor may recommend water limitation, while cautioning you to observe that your dog is adequately hydrated. Hydration levels should be monitored during and following treatment, since dehydration can also bring about serious medical complications. If the dog is dehydrated, electrolytes may also be prescribed.
Living and Management
Observation and comparison against the determined baseline levels are recommended for judging progress.
Prevention
There are currently no known preventative measures for either polydipsia or polyuria.