Frequent Urination in Dogs

We are all familiar with the scene in Jurassic Park where Dr. Ian Malcolm famously states, “When you gotta go, you gotta go,” right when Donald Gennaro bolts towards the bathroom after the T-Rex escapes her pen. Although most of us have never quite reached that extreme of a situation as adults, we can all relate to the pain-aching discomfort of having to “hold it in.” Like you can’t cross your legs forever, your canine companion needs frequent walks to urinate. But how much is too much? Is your dog urinating more frequently than he used to?

There are numerous diseases that can result in a dog drinking an abnormally large amount of water and, as a result, needing to urinate more frequently or in larger amounts. In the following article, we will discuss the causes of increased drinking and urination, as well as when it’s time to have your dog evaluated to determine if one of these diseases is present.

The medical term for increased drinking and urinating in larger amounts is called “polyuria/polydipsia”. For a dog, excessive drinking is defined as consuming over 100 milliliters for every kilogram of weight per day. For a 22 lb dog, this would amount to 1 liter of water per day. Since what comes in, minus what is used, must go out, this results in increased amounts of urination.

Numerous medical causes can result in polyuria/polydipsia. Because there are so many, perhaps it is helpful to break down the list by body system:

Endocrine diseases including Diabetes and Cushing’s disease, are often thought of most commonly. The most common form of diabetes (mellitus) is caused by a pancreatic deficiency where too little insulin is produced, resulting in the inability to drive carbohydrates/sugars into the cells. When properly regulated with diet and insulin supplementation, excessive thirst and urination will improve, and your dog will revert to more normal levels.

There is a less common form of diabetes (central/insipidus) where the body’s production of a hormone called anti-diuretic hormone is low. When this hormone produced in a gland in the brain is low, the result is increased thirst and urination. With medication, this can also be controlled.

Besides endocrine causes, diseases of the liver or kidney can cause increased thirst and drinking. When the kidneys or liver are not functioning normally, excessive body waste products or the inability to eliminate these waste products can drive the body to dilute them by signaling an increased demand for water.

Certain infectious causes can also result in increased thirst. A pyometra or uterine infection or an infection in the kidneys can also drive increased thirst and resulting urination. Some diseases also cause increased calcium levels in the blood, including hyperparathyroidism disease or certain cancers. Finally, other electrolyte disturbances resulting in lower potassium levels can be the inciting cause of increased thirst and urination.

There is another category of increased thirst referred to as Psychogenic Polydipsia. While this condition is not fully understood, dogs with it will have a psychological drive to drink excessive amounts of water.

A few important points. If you do suspect your dog is drinking excessively, do not limit their water intake. Their bodies’ demand for water can be essential in preventing a disease-related crisis. It is also important to make certain to let your dog out more frequently to accommodate the increased burden placed on their bladders while “holding in” their urine, waiting for you to let them out or take them for a walk so they can urinate. Finally, pollakiuria (urinating more frequently in smaller amounts) is a separate medical complaint and the causes of pollakiuria will be discussed in a different article.

If you think your dog is drinking more and, as a result, urinating larger amounts, it is important to schedule an Appointment with one of our veterinary hospitals. During your appointment, our Veterinary Team will obtain a thorough history, including how long the condition has existed, any perceived weight loss, difficulty urinating, and the number of times urinating, as well as ask about other changes you may have noted at home.

Bloodwork, urinalysis, and other tests may be recommended to investigate the cause of polyuria/polydipsia. Fortunately, some of the causes of increased thirst and urination are medically treatable when caught early.

Jeffrey Stupine, V.M.D.
Medical Director, World of Animals Veterinary Hospitals