Water Diabetes in Dogs

Diabetes Insipidus, also called Water Diabetes, is a disease affecting dogs, cats, rats, and occasionally other animals. In this disease, a hormone called ADH is either not secreted in sufficient amounts by the brain, or is not properly recognized by specific cells in the kidneys. This results in extreme thirst and frequent evacuation of very diluted urine. Essentially, the animal’s body is trying to rid itself of more water than is needed for normal urination. This condition is not usually life-threatening, but is inconvenient for the owner and stressful for the animal. However, primary kidney disease, a much more serious condition, may display these same symptoms, and so extreme thirst paired with frequent, lengthy urination is cause for a visit to the veterinarian. Diabetes Insipidus is a disease of the urinary system, where either insufficient amount of antidiuretic hormone (ADH) is secreted by the hypothalamus, or target cells in the kidneys have lost the ability to respond to normal levels of ADH. This lack of communication between the brain and the kidneys results in polyuria with hypotonic urine and extreme thirst.

• Increased intake of water
• Frequent urination of almost clear liquid
• Whining at empty water dish
• Appearing agitated even after a walk

Types

• Central (brain-based)
• Nephrogenic (kidney-based)

• Failure of target cells in kidneys to respond to ADH
• Traumatic head injury causing hemorrhage in the hypothalamus or pars nervosa.
• Neoplasm (tumor) causing lesions in, or damage to, the hypothalamus and pars nervosa

Owners noting frequent urination above what is normal for their pet should monitor the amount of water the animal consumes and the color of their urine. If this pattern of drinking and urination persists, make an appointment with your veterinarian, as the much more serious primary kidney disease could be occurring.

The veterinarian will first rule out primary kidney disease, and then evaluate your pet’s ability to concentrate urine with a water deprivation test. This is done by waiting for the pet to empty their bladder, then withholding food and water for 3-8 hours, which often stimulates ADH to be produced. The animal should be carefully monitored for dehydration, and the test ended if greater than 5% of the animal’s body weight is lost through urine excretion. If the pet is unable to concentrate urine, then an ADH response test may be carried out to better identify the cause of the excessive urination. This is a simple test that involves administering small amounts of a synthetic ADH-replacement, and measuring the specific gravity of the urine (a way of assessing concentration) over a period of 24 hours.

Diabetes insipidus may be controlled by the administration of desmopressin acetate, which mimics the function of ADH. This medication comes in the form of eyedrops or nasal spray, and can be administered at home by the owner. A gradual increase of the dose will be needed to determine the minimum effective amount, but when this amount is found, water may be freely given and no restrictions are needed.

While Diabetes Insipidus is a lifelong condition, it can easily be managed by administration of the eyedrops or nose drops 1-2 times daily, which will control the symptoms and allow your pet a normal, healthy life. There is no need to restrict water once the correct dosage is found.