Frequent urination is a common condition with a number of possible causes. It may either be characterised by the frequent passage of small amounts of urine or passing larger amounts of urine as well as an increase in thirst.
The majority of causes of frequent urination can be split into two categories. Problems with the urinary tract, which can either be due to a partial or full blockage, inflammation, infection, or problems with the kidneys, which have lost their ability to concentrate the urine.
Urinary tract disorders:
The urinary tract consists of the kidneys which filter wastes out of the blood and produce urine, two uteters which urine passes through and into the bladder where it is stored, and the urethra, which passes urine from the bladder to the outside of the body. This entire system can develop inflammation, infection, tumours, stones and crystals. The urethra and ureter are thin like tubes, where stones or crystals can become lodged, leading to a urinary blockage. Common disorders of the urinary tract include:
- Urinary tract infection.
- Urinary tract urolithiasis - Stones or crystals in the urinary tract.
- Cystitis - Inflammation or infection of the bladder.
- Bladder stones.
- Kidney infection.
- Kidney stones.
Your cat may have trouble passing urine, or may only pass a small amount of urine at a time due to stones, crystals or inflammation. Infection or inflammation can also give your cat a sense of urgency to urinate, even if he doesn't have a full bladder.
Male cats are particularly vulnerable to urinary blockages due to their longer and thinner urethra. Female cats are more prone to developing cystitis.
Kidney disorders can result in the cat's kidneys losing their ability to concentrate urine, therefore an increased amount of urine is produced, this, in turn, causes your cat to feel dehydrated and make up the fluid loss by drinking more water. Common disorders include:
Other causes of frequent urination include:
- Diabetes - Is a disease in which the cells of the body build up a resistance to insulin. Insulin is a hormone required to allow glucose (from food) to enter the cells, which provides them with energy. In the diabetic cat, as glucose is unable to enter the cells, high levels build up in the blood, the kidneys try to get rid of this excess glucose by producing more urine to flush it out of the body.
- Spraying - This is seen more often in entire male cats but any cat can spray. The difference between spraying and urinating is that when a cat sprays, he will back up with his rear end facing a vertical object (wall, piece of furniture, tree etc), and deposit spray this way. Whereas both female and male cats squat down to urinate.
Other symptoms which may accompany frequent urination:
- If it is kidney related, increased water consumption commonly occurs as the cat attempts to replace lost fluids. This process is known as 'polyuria/polydipsia' (increased urination and thirst).
- Inappropriate urination can occur in cats who have urinary tract disorders. This may be due to a sudden urge to urinate before they can make it to the litter tray, or often because these conditions are typically painful and they begin to associate their litter tray with pain.
- Blood in the urine (hematuria).
- Anorexia (loss of appetite) is common with kidney disease.
- Genital licking can occur in cats who have urinary tract disorders.
- Straining to urinate is a common symptom of a urinary blockage due to stones or crystals. Complete blockage may occur, particularly in male cats. This is a medical emergency.
How is the cause of frequent urination diagnosed?
Generally, a cat who is frequently passing small amounts of urine and not drinking more is likely to have a urinary tract disorder, a cat who is urinating more (volume and frequency) and drinking more water will have a kidney related disorder.
Your veterinarian will perform a complete examination of your cat and obtain a medical history from you including other symptoms you may have noticed, how long your cat has been displaying symptoms, any medical conditions your cat has, medications he may be on.
He will need to perform some diagnostic tests. These may include:
- Complete blood count - To evaluate for signs of infection such as raised white blood cell count, anemia (which can occur with kidney disease).
- Urinalysis - Can reveal the presence of bacteria, red and white blood cells, urinary stones or crystals, as well as determine how concentrated the urine is.
- Biochemical profile - This may reveal elevated BUN and creatinine levels for kidney related disorders.
- If a urinary tract infection is diagnosed, your veterinarian may choose to perform a culture of the bacteria to determine the best course of antibiotics to treat the infection.
- X-ray or ultrasound may be performed to check for kidney or bladder stones or evaluate the kidney.
- Urine specific gravity to check how concentrated the urine is. Cats with kidney disease often have very dilute urine.
- Kidney biopsy of kidney disease is suspected.
How is the cause of frequent urination treated?
Obviously, treatment depends on the underlying cause and may include:
- Diabetes is managed by a change in diet and if this doesn't bring the disease under control, your cat will need to have insulin injections.
- For acute kidney failure, finding and treating the underlying cause such as poisoning, treating urinary blockages and supportive care.
- Chronic kidney failure is managed in a variety of ways including switching your cat to a low protein and phosphorous diet, phosphorous binders and managing other symptoms such as nausea and high blood pressure.
Urinary tract disorders:
- Antibiotics to treat urinary tract infections.
- If urinary tract infection or stones are diagnosed, increasing your cat's water consumption will be recommended to dilute the urine. Concentrated urine encourages the formation of urinary stones and crystals. Increasing water consumption may include things such as switching your cat over to a canned or raw diet, wetting dry food, encouraging drinking with water fountains etc.
- Prescription diet to alter the pH of the urine for cats suffering from stones or crystals.
- Surgical removal of stones may be necessary in some cases.
- Cats who have become blocked will need to have the blockage removed via manually expressing the bladder, catheterisation or in severe cases, flushing out the obstruction by inserting a thin tube into the penis.
- In severe cases, male cats who become blocked frequently may require a perineal urethrostomy, in which the penis is amputated and a new opening is created in the perineum to allow urine to pass out of the body.