What does it mean when a dog’s urine is diluted? A Complete Guide

This list is huge! How can we possibly determine the cause in my pet?

The search for answers begins with a complete history and physical examination. A pet’s “history” is the information you give the veterinarian about your pet’s illness. History is very important and can provide important clues about the cause of increased thirst and urination. For example, a female pet with a history of being in heat six months ago may have increased thirst and urination because of an infected uterus; an elderly cat that is also vomiting might have hyperthyroid disease; a pet that is eating well but losing weight may have diabetes mellitus (sugar diabetes).

Some drugs can cause increased thirst and urination and you should tell your veterinarian about any medication or supplements your pet is receiving such as anti-seizure drugs (“anticonvulsants”), corticosteroids, and diuretics (“water pills”). It would also help if you measured exactly how much water your pet is drinking in a 24 hour period; this will help your veterinarian determine the severity of the problem.

Physical examination involves looking at all parts of the body, and typically includes listening to the heart and lungs with a stethoscope and “palpating” the abdomen (gently squeezing or prodding the abdomen with the fingertips to detect abnormalities of the internal organs). Physical examination may provide clues about the cause of increased thirst and urination. For example, a cat with small rough kidneys may have serious kidney disease; a dog with a sagging abdomen and hair loss might have Cushing’s disease; a dog with enlarged lymph nodes may have a cancer called lymphoma.

History and physical examination are important first steps, but further testing will likely be required and your veterinarian may recommend screening tests. These are simple tests that provide information about the overall health of your pet and often provide clues about the underlying problem.

The most common screening tests are a complete blood count (CBC), a serum biochemistry profile, and a urinalysis.

What if the cause of increased thirst and urination is not found?

If the screening tests are all normal and the pet continues to pass dilute urine, then testing for a disease call diabetes insipidus should be considered.

Diabetes insipidus is a hormonal disorder in which the kidneys do not concentrate urine as they should. Diabetes insipidus is completely different than diabetes mellitus (the term mellitus refers to the sweetness of the urine in sugar diabetes, while the term insipidus refers to the watery nature of the urine in diabetes insipidus.) The hormone involved is called antidiuretic hormone (ADH). This hormone is released from an area within the brain and acts on the kidney to control how much water goes out in the urine. When the body needs water, ADH levels rise and the kidney holds water back and keeps it from going out in the urine. When there is excess water in the body, ADH levels fall and the kidney allows excess water to flow into the urine.

There are two main forms of the disease:

  • Central Diabetes Insipidus – in which the brain fails to produce proper amounts of ADH,
  • Nephrogenic Diabetes Insipidus – in which the kidneys do not respond to ADH, even though proper amounts are released from the brain.
  • Diagnosis of Chemical Imbalance of Urine in Dogs

    Your veterinarian will first need to know your dog’s complete medical history, the symptoms you have noticed, when the symptoms started, whether the symptoms have changed and when they changed, any changes in your dog’s diet, and changes in your dog’s temperament. The veterinarian will do a complete physical examination including blood pressure and body temperature. Some other tests will need to be done as well, such as:

  • Urinalysis
  • Urine specific gravity
  • Complete blood count (CBC)
  • Blood glucose (test for diabetes)
  • Blood chemical panel (test for high calcium, urea, phosphate, potassium, creatinine)
  • Blood urea nitrogen (BUN)
  • Digital radiology (x-rays) of the kidneys and chest
  • Adrenal gland test (ACTH)
  • The veterinarian may also need to do more tests if these are inconclusive. These other tests are:

  • Ultrasound
  • CT scan
  • MRI
  • Biopsy (kidney, liver)
  • 5 Signs that your Dog has a Urinary Problem | How to Spot Urinary Problems in your Dog?

    The kidneys are incredibly important organs for our pets and ourselves that are often underappreciated. Their most important job is to eliminate toxins from the blood through the production of urine.

    The kidneys are built to last and are very resilient, which is why chronic kidney disease often sneaks up on our pets. Chronic kidney disease refers to when the kidneys are no longer able to fulfill their most basic function of producing normal urine to eliminate toxins from the body. When chronic kidney disease sets in, the first sign is that the kidney can no longer produce concentrated urine. When our pets become dehydrated, the kidneys will produce concentrated urine to conserve water in their body instead of allowing it to go to waste in producing urine. As an owner, one of the most common signs you might notice as a result of this is that your pet will urinate more because they cannot concentrate their urine and that they will drink more to compensate for this loss of water. What is most surprising about this fact, though, is that the kidneys lose the ability to concentrate urine when they have lost 66% of their normal function. That’s right—the kidneys must lose two-thirds of their normal function before they can’t concentrate urine anymore. Another way to look at it is the kidneys only have 33% remaining normal function once this occurs.

    After urine concentrating ability is lost, the next stage of chronic kidney disease is that the kidneys can no longer keep normal kidney values, BUN and creatinine, on bloodwork. The ability to keep the kidney values within the normal range on bloodwork is lost when the kidneys have lost 75% normal function, or when they have only 25% normal function remaining. At this stage, beyond a pet having increased thirst and urination, they will often develop weight loss, lethargy, decreased appetite, and vomiting. These signs will worsen as the kidney function worsens.

    With our pets only showing clinical signs of chronic kidney disease after a significant loss of function and some of these signs overlapping with other diseases (diabetes mellitus also famously causes increased thirst and urination like chronic kidney disease), it is vital that our pets be screened for normal kidney function routinely through bloodwork and urine testing. If you notice your pet experiencing signs of chronic kidney disease, take them for a veterinary visit ASAP!

    About Dr. Ramsey Dr. Grant Ramsey is the head of internal medicine at MissionVet Specialty & Emergency. He received his doctorate of veterinary medicine at Mississippi State University. He completed a small animal rotating internship at Coral Springs Animal Hospital and a small animal internal medicine residency at Gulf Coast Veterinary Specialists. In his free time, he enjoys meditating, playing video games, and exploring San Antonio.