Diabetes insipidus in dogs is a rare condition that most pet owners have never heard of. This is also known as water diabetes, not the typical sugar diabetes (diabetes mellitus) that most people are familiar with. The disease affects the dog's ability to regulate water balance and results in excessive thirst and urination. Dogs with diabetes insipidus will produce abnormally large amounts of urine and will constantly be thirsty. The condition can be caused by several factors, including tumours, head injuries, and cysts. Unfortunately, diabetes insipidus cannot be cured but it can be managed with proper therapy. Prognosis is often good for dogs with diabetes insipidus when they receive the appropriate treatment.
As mentioned, diabetes insipidus in dogs is a disorder of water regulation. It occurs when there is a problem with the antidiuretic hormone (ADH) from the pituitary gland in the brain. This hormone regulates thirst and helps the body to reabsorb water via the kidneys. When there is a problem with ADH production, it results in the excessive production of urine and thirst. Diabetes insipidus is different from diabetes mellitus, which is the more common form of diabetes that most people are familiar with. Diabetes mellitus is a disorder of sugar metabolism, while diabetes insipidus is a disorder of water metabolism.
There are two types of diabetes insipidus in dogs: central diabetes insipidus and nephrogenic diabetes insipidus. Central diabetes insipidus is an uncommon type of diabetes insipidus in dogs and is caused by a problem with the pituitary gland or hypothalamus in the brain. Nephrogenic diabetes insipidus is more common and is caused by a separate condition or disease, or corticosteroids that interfere with the kidney's ability to receive ADH hormone.
Central diabetes insipidus can be caused by head trauma, neoplasia, ischemia (lack of blood flow), and hypothalamic-pituitary malformations, among other things. For example, tumours in the brain can lead to central diabetes insipidus in dogs. Cysts, head injuries, and other problems with the pituitary gland or hypothalamus can also cause the condition. Nephrogenic diabetes insipidus is most often caused by a variety of diseases and conditions, but can also be caused by certain drugs, such as corticosteroids.
Dogs with diabetes insipidus often have a profound increase in thirst and urination. Occasionally, they may also experience anorexia and weight loss. If they're deprived of water, severe dehydration can occur rapidly.
In addition to a physical examination and routine blood work to rule out other diseases, your veterinarian will likely proceed in performing a urinalysis. The urinalysis will reveal extremely dilute urine, almost the same concentration as that of water. To diagnose diabetes insipidus in dogs, there are two tests your veterinarian can perform.
This is the most commonly used test to diagnose diabetes insipidus in dogs and is only to be performed under the supervision of your veterinarian. It involves withholding water from your dog for 12-24 hours and monitoring their weight, urine output, and specific gravity of the urine (concentration). If your dog has diabetes insipidus, they will not be able to concentrate their urine and will become dehydrated.
During the test, it's important to weigh your dog every few hours and monitor its urine output. If they start to show signs of dehydration, such as lethargy or sunken eyes, the test will need to be stopped and fluids will need to be administered intravenously.
After the 12-24 hour period, water is then re-introduced and your dog's urine output, weight, and concentration are monitored for the next 12 hours. An increase in water intake and urine output should occur within the first few hours after the re-introduction of water.
A trial course of desmopressin (synthetic ADH hormone) may be used in place of a modified water deprivation test. Desmopressin can be given orally, intranasally (nasal spray), or onto the eye. Water consumption and the concentration of the urine are monitored closely for 5-7 days. In dogs with central diabetes insipidus, water intake is dramatically reduced and urine concentration increases by more than 50%.
There is no cure for diabetes insipidus, but it can be managed with treatment. The goal of treatment is to reduce the amount of urine produced and maintain hydration.
The most common treatment for diabetes insipidus is desmopressin acetate, a medication that helps to increase water reabsorption in the kidney. It is available as an intranasal spray or oral tablet. Desmopressin acetate is usually given two to three times daily.
In some cases, treatment may also include the use of a low-salt diet and thiazide diuretics. Thiazide diuretics help to increase water reabsorption in the kidney and reduce urine output.
Central diabetes insipidus in dogs is often irreversible but manageable. Studies have revealed that when properly diagnosed and treated with desmopressin, the prognosis for diabetes insipidus in dogs is good. Long-term prognosis however depends on the underlying cause of the condition.
For example, if diabetes insipidus is caused by a tumour, the prognosis will depend on the type and location of the tumour and whether it is malignant or benign. If diabetes insipidus is caused by head trauma, the prognosis will depend on the extent of the injury.
In conclusion, diabetes insipidus in dogs is a rare condition that affects the dog's ability to regulate water balance. Dogs with diabetes insipidus will excessively produce urine and experience excessive thirst. The condition is caused by a problem with the dog's antidiuretic hormone (ADH) from the pituitary gland in the brain and regulates thirst. Central diabetes insipidus can be caused by many factors, including tumours, head injuries, and cysts. Diabetes insipidus cannot be cured but can be managed. Prognosis is often good with the appropriate therapy.
