When a cat is unable to pass urine it is definitely an emergency, they can become very distressed and painful, in addition to becoming very ill very quickly. Straining to urinate does not necessarily indicate an obstruction right away, however if you think your cat is unable to pass urine at all, despite frequent visits to the litter tray, then you should contact your local veterinarian immediately.
What is urinary tract obstruction in cats?
Urinary tract obstruction is almost exclusively seen in male cats, and is where your cat will be unable to pass any urine at all. This most commonly appears as your cat frequently visiting the litter tray and straining but not passing any urine, or very small amounts of urine or blood, and often they will vocalise whilst doing this. Urinary tract obstruction can very rapidly cause damage to the kidneys, and the build up of waste products in the body can cause problems with the heart. For these reasons urinary tract obstructions are a life-threatening condition and require urgent veterinary treatment.
Signs that your cat may have a urinary tract obstruction:
- Frequent, non-productive trips to the litter tray, often with straining and vocalisations
- Passing very small amounts of blood or urine when straining to urinate
- Lethargy or hiding away
- Vomiting or reduced appetite
- Abdominal discomfort
- Grooming around their genitals frequently
How does urinary tract obstruction occur?
Urinary tract obstruction can be the result of a number of underlying processes, with the most common being a physical obstruction of the urine flow with with either a mucus plug formed from inflammatory cells and debris from the bladder, or a bladder stone (urolith), however functional obstruction, where the muscles inside the urethra spasm and become inflamed preventing urine flow also occurs.
The mucus plug will often form when there is already inflammation occurring in the bladder, and similarly with the spasm and inflammation of muscles inside the urethra, will often occur following a stress cystitis.
Bladder stones, or uroliths, can form for a number of reasons, such as underlying infection, urine that is over concentrated, or a predisposition for stone formation based on the pH of your cat’s urine.
How is urinary tract obstruction managed?
Overall the urinary tract obstruction is managed by stabilising the cat and removing the blockage of the urethra to restore normal urine flow, usually followed by supportive treatment to allow the kidneys to recover and flush out any waste products that have built up in the body. The supportive treatment also allows the urethra to recover from any inflammation and reduces the chance of it becoming blocked again in the short term.
Depending on how long the blockage of the urethra has been present, the cat will need a blood sample to check how much stabilisation is needed prior to sedation or general anaesthesia to unblock the urethra. If the blockage is functional then sedation may be all that is required to relax the muscle enough to allow for urine flow, however in most cases a general anaesthetic is needed to place a urinary catheter to flush any material blocking the urethra back into the bladder to restore urine flow. Once the urinary catheter has been placed it is often secured in place to allow the urethra to recover from inflammation and preserve urine flow over the next 24-48 hours. A combination of fluids and medications will help the kidneys, bladder, and urethra recover from the inflammation and damage caused by the blockage.
How can future blockages be prevented?
Managing the risk of future blockages will depend on the reason for the blockage in the first place, and so at the time of treating the urinary tract obstruction your veterinarian may recommend taking some samples to investigate the underlying cause.
If a bladder stone (urolith) was the underlying cause of the obstruction, then analysing one of the stones to see what type of bladder stone it is will enable an effective plan to be made to prevent further bladder stones. This usually involves a change in the diet to reduce the likelihood of future stone formation, and encouraging water intake to reduce the concentration of the urine, as this also predisposes to bladder stone formation.
If the underlying cause is a mucus plug or a functional obstruction then the underlying cause is much more likely to be related to idiopathic cystitis (cystitis of unknown cause), and so managing the risk factors for this will reduce the likelihood of further blockages. The main risk factors for idiopathic cystitis revolve around a cat’s inappropriate stress response leading to inflammation in the bladder, so by minimising stress and sudden changes in your cat’s life you can reduce the risk of idiopathic cystitis. Things you can consider to reduce stress in the home environment for your cat include:
- The use of pheromone diffusers (such as a Feliway diffuser) to send relaxing messages to your cat in their home environment
- Providing extra resources to eliminate competition between cats at home (for example adding in extra food and water bowls, and litter trays)
- Reducing stress from local cats (for example discouraging neighbouring cats from entering your property, covering windows where you cat can see other cats outside)
- Minimising changes to your household or routine (for example when or what you feed your cat, where furniture is or any home renovations)
- Providing plenty of outlets for your cat, such as scratching posts and areas to hide
- In some cases using stress relieving supplements can be useful (e.g. zylkene)
In addition to minimising or preventing these risk factors, there are some supplements that can be useful to protect the bladder wall and prevent it from being inflamed. Before using these you should check with your local veterinarian that there is not any other cause of inflammation in your cat’s bladder, and ensure that the current episode of cystitis fully resolves otherwise they will still be at risk of having an obstruction.
Cats who have had a urinary obstruction once are at increased risk of becoming blocked again, and so it is important to consider all of the possible underlying causes with your veterinarian, including diet, weight, your cat’s disposition, and other lifestyle factors. Once you have identified the changes to be made then hopefully you can prevent your cat from being blocked again, and live a healthy and stress free life.