Medical Causes of Inappropriate Urination in Cats

  • Author

    • Arthritis
    • Declawing
    • Cystitis
    • Bladder stones
    • Urinary tract infection
    • Diabetes
    • Kidney disease
    • Cognitive dysfunction
    • Hyperthyroidism

    Inappropriate urination occurs when a cat urinates outside the litter tray which may have a behavioural or medical cause. Medical causes can be further divided into pain, increased urine production, increased urgency to urinate and cognitive dysfunction.

    Inappropriate urination differs from urine spraying as it is deposited on horizontal surfaces (flooring, bedding etc), while spraying is on vertical surfaces such as walls and doors.

    Medical causes of inappropriate urination


    Arthritis is a painful condition in which the shock-absorbing cartilage which cushions the joints wears down and is eventually lost. Once this occurs the bones rub against each other which is extremely painful. The disease is progressive, usually starting in middle age and becoming worse in the cat’s senior years.

    Pain can make it difficult for the cat to access, or climb into or out of the litter tray.

    Declawing pain

    Declawing is the surgical removal of the claw which is attached to the distal phalanx (toe bone). Cats are toe walkers, so it is easy to imagine how painful it is for the cat to walk when the last toe has been amputated.

    Most cats will recover from post-surgical pain, however, some will experience prolonged pain.


    Inflammation or infection of the urinary bladder, which has several underlying causes including stress, dehydration, holding on to urine for too long (after prolonged bad weather, or unhappy with the litter tray), diabetes, bladder stones and idiopathic (no known cause).

    There is a higher incidence of cystitis in female cats due to their narrower urethra, which makes it easier for bacteria from the anal region to reach the bladder.

    Bladder stones

    Bladder stones are rock-like deposits in the urinary bladder. The cause of bladder stones is concentrations of certain minerals in the urine. The most common type is struvite, which accounts for 50% of stones, other types include calcium oxalate, ammonium urate, calcium-ammonium-phosphate, urate, cystine and compound (stones that contain different materials).

    Urinary tract infection

    A urinary tract infection (UTI) occurs when the usually sterile urinary tract is colonised by bacteria (or less frequently viruses). The urinary tract is is a system in the body involved in the formation, storage and elimination of urine. It includes two kidneys (which filter and clean the blood, forming urine in the process of removing excess water and waste products), two ureters (which transport urine from the kidneys to the bladder), the bladder (which stores the urine until voiding) and the urethra which transports urine from the bladder to outside.

    There is an increased incidence of UTI’s in cats with diabetes, females, cats who hold onto their urine for too long, male cats who have had a perineal urethroscopy and any cat who has had a recent catheterisation.


    Diabetes is a common disease where the cells build up a resistance to insulin, a hormone necessary for glucose to enter the cells, which leads to elevated blood sugar levels.

    There is a higher incidence of diabetes in obese and middle-aged to senior cats. Complications of diabetes include ketoacidosis, nephropathy, neuropathy, hypoglycemia, cataracts and urinary tract infections.

    Increased blood glucose levels trigger the kidneys to remove the excess by increasing urination, this, in turn, leads to increased thirst (polyuria/polydipsia) to replace water lost during urination.

    Kidney disease

    Kidney disease is a loss of kidney function, it can be acute or chronic. Chronic kidney disease is a slow and progressive disorder that usually affects middle-aged to senior cats. Up to 70% of kidney function will be lost before symptoms present.

    As kidney function declines, the kidneys lose their ability to concentrate urine, which leads to increased urination and as with diabetes, this causes the cat to drink more water.

    Urinary blockage

    A urinary blockage can occur when an obstruction blocks the flow of urine out of the urethra. Obstructions may be partial or complete. Male cats are at increased risk due to their long and narrow urethra. Blockages can be caused by urinary crystals, inflammation, tumours, blood clots and scarring from previous catheterisations.

    If the blockage is incomplete, the cat may still be able to pass small amounts of urine, once it is complete, the cat cannot pass urine at all. This is a medical emergency, which requires immediate treatment to unblock the cat.

    Cognitive dysfunction

    Also known as feline dementia, cognitive dysfunction (CDS) can occur in cats as they enter their senior years. One study found that close to 30% of cats between 11 and 14 show signs of CDS, this figure jumps up to 50% in cats over 15 years of age and up to 80% in cats aged 16 and onwards.

    The cause of cognitive dysfunction is poorly understood, it is thought it may be due to the development of plaques developing on the brain or reduced blood flow due to damage to the blood vessels or chronic free radical damage.

    The acronym DISHAAL is used to summarise classic signs of CDS in cats.

    1. Disorientation
    2. Interactions (changes in interactions with owners, other pets and the environment)
    3. Sleep-wake cycle disturbances
    4. Housesoiling
    5. Activity (changes in/repetitive)
    6. Anxiety
    7. Learning


    Feline hyperthyroidism is a common endocrine disorder caused by a benign hormone-secreting tumour on the thyroid gland. This gland is responsible for the production of two hormones, T3 triiodothyronine and T4 thyroxine, which control metabolism. Increased levels of circulating hormone speed up the cat’s metabolism causing a range of clinical signs including increased urination and thirst.

    The average age of cats is 13, and the disease is rarely seen in cats under ten. Hyperthyroidism can run concurrently with chronic kidney disease, which is also common in senior cats, and in fact, can mask CKD due to the increased metabolism speeding up kidney filtration.


    The veterinarian will perform a complete physical examination and obtain a medical history from you, including how long the cat has been urinating outside the litter tray and any additional symptoms you may have noticed such as drinking more, weight loss, genital licking and blood in the urine.

    Baseline tests include biochemical profile, complete blood count and urinalysis can provide information on the cat’s overall health and pick up urinary tract infections, crystals in the urine, blood sugar levels as well as kidney function.

    Depending on the veterinarian’s index of suspicion, additional tests may be necessary including ultrasound to look for stones in the bladder and T3 and T4 tests for hyperthyroidism.


    This will depend on the underlying cause but may include stone dissolving diets or surgery for cats with bladder stones, increasing water intake, antibiotics, prescription diets to manage hyperthyroidism, kidney disease and diabetes, surgery, and radioactive iodine treatment for cats with hyperthyroidism.

    Keeping litter trays clean can also help as dirty litter trays can lead to house-soiling. There should be one tray per cat, plus one extra, and each floor of the house should have at least one tray.

    Cats with arthritis will benefit from a tray with low sides and ensure litter trays are easy to access. As a cat ages, he or she will find it increasingly hard to navigate stairs.

    It is important to keep things routine for cats with cognitive decline, moving trays around can add to the confusion. Keep everything in the same place, and maintain the same daily routine.

    Cystitis can be exacerbated by stress, therefore work towards a stress-free and harmonious household, this is especially crucial for multi-cat homes. Ensure each cat has his or her key resources including a litter tray, food and water bowl and plenty of cat trees and perches so that a cat can have some time out they need to.

    Declawing pain should resolve within a few weeks post-surgery, if the cat is still experiencing pain, speak to your veterinarian.


    • Julia Wilson, 'Cat World' Founder

      Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio