Excessive Thirst in Dogs

By Catherine Troiano

If your dog's water bowl has been requiring more frequent fill-ups and your furry friend requests more outings to urinate than he used to, these are red flags that warrant some diagnostic investigation from your veterinarian. Polydipsia, an increase in water intake, and polyuria, the increased urinary output that results, can be indicative of a few common canine illnesses.

Canine Diabetes Mellitus

Canine diabetes mellitus is a metabolic condition in which the dog's system is unable to process and utilize the glucose in his bloodstream because his pancreas cannot produce adequate levels of insulin. Canine diabetes mellitus typically strikes dogs during their middle age to senior years. Some additional signs and symptoms of canine diabetes mellitus that accompany polydipsia and polyuria include:

  • Increased appetite.
  • Weight loss.
  • Cataract formation.
  • Increased incidents of urinary tract infections.
  • Weakness.

If your dog exhibits any of these symptoms, your veterinarian will take blood and urine samples to diagnose canine diabetes mellitus. Once the diagnosis has been confirmed, your dog will require lifelong treatment and periodic monitoring to manage his condition. Treatment protocols include daily insulin injections and a low carbohydrate-high protein diet.

Cushing's Disease

Cushing's disease occurs when your dog's pituitary gland secretes abnormally high levels of adrenocorticotropic hormone, which overstimulates the adrenal glands to overproduce corticosteroid hormones. Along with hypothyroidism and diabetes, Cushing's disease is one of the three most common hormone-related health conditions to afflict older dogs. In addition to polydipsia and polyuria, you may observe the following signs and symptoms if your dog has Cushing's disease:

  • Increased appetite.
  • A pot-bellied appearance.
  • Excessive panting.
  • Hair loss on the torso.
  • Incontinence.
  • Muscle weakness and exercise reluctance.

To confirm a Cushing's disease diagnosis in your dog, your veterinarian will need to perform specific laboratory blood tests. One test is called a low dose dexamethasone suppression test, and the other blood test is called an adrenocorticotropic hormone stimulation test. Once your veterinarian has the results of these tests and of the standard complete blood count, chemical profile and urinalysis, he or she will determine a treatment plan for your dog. Cushing's disease is most commonly managed with lifelong oral medication and periodic blood monitoring tests.

Chronic Renal Failure

As dogs age, wear and tear of the kidneys contributes to their progressive degeneration and decreased function. The first symptoms of this degenerative condition that is known as chronic renal failure are polydipsia and polyuria. Before the process of chronic renal failure began, the kidneys were able to perform their task of filtering waste from the bloodstream. No longer able to carry out their function as efficiently, your dog is prompted to consume an increasingly larger volume of water in his body's attempt to flush these wastes through. Additional signs and symptoms of chronic renal failure include:

  • Dehydration.
  • Poor coat condition.
  • Vomiting.
  • Weight loss.
  • Decreased appetite.
  • High blood pressure.

Your veterinarian will take blood and urine samples from your dog to confirm a diagnosis of chronic renal failure. Unfortunately, by the time the symptoms of chronic renal failure present, the kidneys have suffered significant wear and damage. Chronic renal failure is a progressive disease that cannot be reversed. The goals of treatment will focus on slowing the progression of the disease, providing symptomatic relief and extending your dog's quality of life for as long as possible. Treatment plans for chronic renal failure typically include a low-protein diet and fluid therapy. As the disease progresses, medications may be prescribed to combat some of the effects of the illness, such as high blood pressure, low blood potassium levels, anemia and abnormal blood calcium/phosphorus ratios.

Side Effect, Not Symptom

If your dog is currently taking certain drugs, be sure to familiarize yourself with the potential side effects. Some medications can cause an increase in water consumption, including:

  • Anti-inflammatory drugs, such as prednisone.
  • Anti-seizure drugs, such as phenobarbital.
  • Diuretic cardiac drugs, such as furosemide.

Low-protein diets, high-sodium foods or feeding exclusively dry kibble can cause an increase in your dog's thirst.

If your dog seems to be spending more time at his water bowl than he used to, whining to go outdoors more often and waking you up for nocturnal outings to eliminate, these are indications that it is time to schedule an appointment with your veterinarian. From the day you suspect an increase in your dog's water consumption until the day of your dog's veterinary appointment, measure the amount of water you put into his bowl and keep track of how often the bowl needs to be refilled. This will provide your veterinarian with an accurate measurement of how much water your dog is currently taking in. Making a diagnosis before an illness progresses and inflicts adverse effects on your dog is essential in helping you to take control of your dog's health and manage his condition for a longer and improved quality of life.