What Causes Excessive Thirst and Weight Loss in Dogs?

The incidence of diabetes in the dog population is not very high, but all veterinarians are called upon to deal with this complicated disorder from time to time. Diabetes occurs more frequently in female dogs and is more common in older dogs over 5 years old. There seems to be no breed susceptibility, but it has not been reported in boxer dogs.

Why is my dog losing weight and drinking lots of water?

The underlying cause of diabetes in dogs is a deficiency of insulin in the animal. Insulin is a hormone secreted by specialized cells within the pancreatic gland.

In a normal dog, there is a balance between the levels of insulin and two hormones secreted by the pituitary gland. This balance keeps the level of blood sugar constant by allowing excess glucose formed from the breakdown of food to be stored in the liver.

When there is a deficiency of insulin glucose storage within the liver does not occur and excess glucose accumulates in the blood. As the blood sugar levels increase, glucose is lost from the kidney cells into the urine.

Water is drawn from the kidney cells to balance the rise in osmotic pressure of the urine causing the dog to compensate by drinking water excessively.

Increased thirst is one of the first symptoms of diabetes in dogs. The constant loss of glucose through the kidneys prevents the dog from utilizing the full energy potential of its daily food so that it becomes excessively hungry.

Even if extra food is available the dog loses weight, as another important function of insulin in the body is to build protein and fat from surplus carbohydrates. The hormones from the pituitary gland exacerbate the weight loss by promoting the breakdown of stored protein and fat to form more glucose and fatty acids.

The symptoms of diabetes vary according to the degree of insulin insufficiency and the length of time that the condition has been present. At first, the dog may only have increased thirst and loss of weight, despite eating more.

As more of the body’s reserves of fats and proteins are used, the by-products of this breakdown accumulate in the blood and begin to produce toxic effects. Vomiting and dehydration soon lead to muscle weakness, labored breathing, and eventually collapse and death.

What to do if my diabetic dog loses weight and drinks a lot of water

Treatment of diabetes is possible by administering a daily dosage of insulin by injection.

The amount of insulin necessary to supply the daily needs is found by hospitalizing the dog and gradually increasing the dosage of insulin until the blood sugar falls to an acceptable level.

This dosage of insulin is directly related to the amount of food eaten and the amount of exercise taken by the dog daily. It is most important to keep both the amount of food and type of food constant. Exercise decreases the amount of insulin required, so that marked changes in the daily activity of the dog must be avoided.

Treatment of dogs showing toxic effects from prolonged insulin insufficiency is very difficult, as irreversible changes may have occurred before treatment is begun.

Any dog showing the early warning signs of loss of weight and excessive thirst should be examined by your veterinarian as the treatment of uncomplicated diabetes is quite feasible.



3 Responses

  1. I have a Great Dane mix. He has had every test done except an exploratory surgery. He is ten years old and I don’t know if I want to put him through that. He has lost 25 plus pounds at this point and throws up not food but just stomach bile. No one can seem to find anything from his tests. He also seems to be drinking a ton more water. Could he have developed diabetes?

    1. One of the causes of his vomiting it up is because he was drinking too much for his body to handle at the time, therefore throwing it back up.

      Many conditions in dogs can lead to excessive water intake, including kidney disease, diabetes, and cancer, etc. You can get a blood test and urine test for your dog if there is any doubt of diseases or other unseen abnormalities.

  2. I have had several blood test for diabetes, cancer etc., stays showing nothing, urine samples showing a diluted ph is all! One kidney is slightly larger than other. All functions are normal. X-ray found bladder stones. Vet suspects cancer somewhere because my dog keeps loosing unexplained weight, drinks and urinated every 15 to 20 minutes. She eats well and I feed her extra or she would be down to 5 pounds if that. All her bones are showing now, ribs etc. She’s a mystery! Her pads on paws are swollen and look like pancakes when she stands on them. She had antibiotics for them for 2 weeks and it helped, now they are back the same as before. Her calcium level and white blood cell are elevated. Every test is negative for all things tested. This is why my vet suspects cancer some where! I’m at a loss and don’t know what to expect for my precious baby! Any thoughts please!

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