Why is my house-trained pet urinating in the house?
Inappropriate urination or urinary “accidents” happen in well-trained pets for many reasons, including:
- inflammation or infection of the urinary or reproductive tracts
- estrogen deficiency in spayed female dogs
- diseases that cause increased urination, such as kidney failure, diabetes mellitus (sugar diabetes), diabetes insipidus, and hyperadrenocorticism (over-active adrenal glands, also called Cushing's disease)
- neurological disease affecting bladder control
- behavioral issues such as submissiveness or territoriality
- certain medications, such as corticosteroids, that may cause increased thirst and urination leading to urinary accidents
How is the problem of inappropriate urination investigated?
The search for answers starts with a complete history and physical examination. A pet’s history is the information you give your veterinarian about your pet’s illness. This information can provide important clues about the underlying problem. For example, an older, spayed, female dog with a history of “leaking” urine when she lies down may have hormone-responsive urinary incontinence; a pet that strains to urinate may have inflammation or blockage of the urinary tract; a puppy that rolls on its back and urinates is being submissive; a dog that drinks excessively and urinates a lot may have diabetes.
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). In a pet that is having urinary accidents, the physical examination may reveal such things as vaginal discharge in a female pet, suggesting vaginitis; large, tense bladder, suggesting urinary obstruction; or abnormally shaped or sized kidneys, suggesting kidney disease.
If history and physical examination are unhelpful, then further testing will likely be needed, and your veterinarian may recommend doing screening tests. These are a series of simple tests that provide information about the overall health of the pet, and often provide further clues about the underlying problem.
What screening tests are recommended and what can they tell us?
The basic screening tests include a complete blood count (CBC), serum biochemistry profile, and urinalysis. To complete these tests, two blood samples and a urine sample must be collected from your pet.
Complete Blood Count (CBC)
A complete blood count is a simple blood test that provides information about the different cell types in blood. These include red blood cells, which carry oxygen to the tissues, white blood cells, which fight infection and respond to inflammation, and platelets, which help the blood to clot. The CBC provides details about the number, size, and shape of the various cell types, and identifies the presence of abnormal cells in circulation. See handout “Complete Blood Count” for more information.
The CBC is often normal in pets that are urinating inappropriately. However, changes that may be seen include the following:
- Decreased numbers of red blood cells, decreased hemoglobin, and decreased packed cell volume (PCV) indicate anemia. Anemia may be due to chronic kidney disease or other chronic illnesses, including cancer.
- Increased numbers of white blood cells may indicate infection of the kidneys, or secondary infections due to diabetes mellitus or Cushing’s disease.
- Increased numbers of neutrophils (a type of white blood cell) may indicate an underlying infection, the use of corticosteroid medication, or Cushing’s disease.
Serum Biochemistry Profile
A serum biochemistry profile refers to the chemical analysis of serum, which is the pale-yellow liquid part of blood that remains after the cells and clotting factors have been removed. There are many substances in the serum, including proteins, enzymes, fats, sugars, hormones, and electrolytes. Measuring the levels of these substances in the blood provides information about the health of the body’s organs and tissues, as well as the metabolic state of the animal. Changes and abnormalities found in the biochemistry profile can help diagnose a variety of diseases and disorders. See handout “Serum Biochemistry” for more information.
In a pet that is urinating inappropriately, the serum biochemistry profile could show:
- Elevated glucose, suggesting diabetes mellitus
- Elevated kidney values, suggesting kidney disease
- Decreased urea, which may indicate diabetes insipidus or liver disease
- Mild elevation of liver enzymes, which is often seen with Cushing’s disease or with the use of corticosteroid medication
Urinalysis
Urinalysis is a simple test that analyzes the physical and chemical composition of urine. It measures how well the kidneys are working, identifies inflammation and infection in the urinary system, and helps to detect diabetes and other metabolic disturbances. Urinalysis is important for the proper interpretation of the serum biochemistry profile and should be done at the same time as blood testing. See handout “Urinalysis” for more information.
In a pet that is urinating inappropriately, a urinalysis could show:
- Dilute urine (pale watery urine), which is associated with conditions such as kidney disease, diabetes insipidus, diabetes mellitus, Cushing’s disease, and the use of corticosteroid medication
- Red blood cells or white blood cells, which indicate inflammation of the kidneys, urinary system, or reproductive system
- White blood cell casts (tubular clusters of white blood cells), which indicate inflammation of the kidneys
- Crystals, which may indicate underlying bladder stones
- Bacteria, fungi, and yeast, which can indicate bladder infections (bacterial bladder infections are common while yeast and fungal infections are uncommon)
- Abnormal bladder cells, which may be a sign of underlying bladder cancer
What if all the screening test results come back normal?
If all the tests results come back normal, then inappropriate urination may be due to one of the following reasons.
A) Behavioral problems, including:
- Submissive urination. A puppy that rolls on its back and urinates is being submissive. It usually happens when the puppy is approached by a larger dog or an adult member of the family.
- Territorial marking. If there are multiple pets in the household, competition between animals may lead one or more of them to urinate inappropriately to “mark” their territory.
- Cats and their litter boxes. Some cats prefer not to use a dirty litter box and may urinate elsewhere. Male cats with a history of painful urinary blockage may associate the litter box with pain and choose to urinate somewhere else.
B) Hormone-responsive urinary incontinence. In this condition, there is a slow, involuntary “leaking” of urine from the bladder when the pet is lying down or sleeping. It is usually seen in older, spayed, female dogs and is associated with decreasing levels of estrogen in the blood, which causes weakening of the muscles that control urination.
What additional tests might be recommended for a pet that is urinating inappropriately?
There are several additional tests that might be recommended, depending on the results of a pet’s history, physical examination, and screening tests. Some examples of additional tests include:
- Testing for diseases that cause increased thirst and urination. These include diabetes mellitus, Cushing’s disease, diabetes insipidus, and renal failure.
- Culture and sensitivity. This test helps determine if bacterial bladder infection is present and identifies which antibiotic should be used to treat the infection.
- Cytology. Bladder cells taken from urine are examined under the microscope to diagnose bladder cancer.
- Imaging studies. Radiographs (X-rays) or ultrasound of the kidneys and urinary system may be recommended to look for stones or tumors.
- Stone analysis. Bladder stones are sent to a referral laboratory to be analyzed for their mineral content. Based on the results, dietary changes can often prevent recurrence of bladder stones.
