Diabetes Insipidus in Dogs

Diabetes insipidus can be of two types:

Central diabetes insipidus (CDI): CDI originates from the brain. Damage to the hypothalamus, the part of the brain that produces antidiuretic hormone, leads to reduced production of ADH. Damage to the hypothalamus can be caused by birth defects, cancer, trauma, or infections. Dogs with central diabetes insipidus may show additional symptoms related to brain tissue injury, such as severe lethargy, seizures, tremors, uncoordinated gait (ataxia) or unusual behaviors.

Nephrogenic diabetes insipidus (NDI): NDI originates from the kidneys, which in this case do not respond properly to antidiuretic hormone. NDI can be caused by birth defects, metabolic conditions, or adverse reaction to medications.

Diabetes insipidus is a very rare condition in dogs and generally has a good prognosis.

Dogs suffering from diabetes insipidus are often unable to consume enough water to compensate for excessive urination which can lead to dehydration. Symptoms of diabetes insipidus require prompt veterinary assessment.

Dogs showing symptoms of severe dehydration such as tacky gums, severe lethargy, and sunken eyes require emergency veterinary attention, as coma or death can result from prolonged dehydration.

Diabetes insipidus is caused by either lack of production of ADH or lack of response to ADH.

Lack of production and lack of response to ADH can be caused by:

• Traumatic injury
• Adverse reaction to medication
• Cancer
• Underlying metabolic conditions such as hyperadrenocorticism
• Birth defects affecting the brain or kidneys
• Kidney disease or infection

Diabetes insipidus also leads to dehydration. Signs of dehydration include prolonged skin tent, sunken eyes, and tacky mucous membranes.

Diabetes insipidus is very rare in dogs. Ruling out other causes of the symptoms is the first step in diagnosis. Dogs presenting with symptoms of DI require the following diagnostics to determine the best course of treatment:

• Physical examination
• Blood tests
• Urine analysis
• Hormone level testing
• Diagnostic imaging
• Water deprivation test: this is a specific test used to confirm DI. The veterinarian withholds water for 3-8 hours. After the withholding period, the urine is analyzed. If the dog still has diluted urine the diagnosis is confirmed
• ADH response test: A dose of ADH is given to the dog. If the dog’s urine becomes more concentrated, then central diabetes insipidus is confirmed. If there is no increase in urine concentration, then nephrogenic diabetes insipidus is confirmed.

Treatment for diabetes insipidus depends on the underlying cause.

In cases of CDI, the treatment is supplemental ADH medication. In cases of NDI , the treatment includes use of diuretics to reduce the risk of dehydration and to treat the underlying cause, such as removing causative medications or treating kidney infections.

If the dog is suffering from severe dehydration, hospitalization may be needed to administer IV fluids.

The prognosis for diabetes insipidus is generally good and depends on the underlying cause.

Diabetes insipidus caused by a reduction in ADH production is a lifelong condition. The prognosis is generally good with proper lifelong treatment.

Kidney-originated DI usually has a good prognosis with appropriate treatment, which typically focuses on treating the underlying condition.

Diabetes insipidus is not contagious. Frequent veterinarian checkups can help to identify potential conditions in their early stages, improving the animal's general health.

Diabetes insipidus is very rare in dogs.

• Supplemental ADH
• Treatment of underlying conditions