You notice that your male cat has been acting strangely around the litter box. He may seem restless, repeatedly visiting his litter box and straining unproductively, only to leave the litter box without actually having done anything in it. Is he constipated? Is he struggling to urinate? Is this an emergency?
These are all important questions often asked by many cat owners. This quick guide will help explain urethral obstructions in male cats, and why you should be keeping an eye out for this feline emergency. 
What is a ‘blocked cat’?
A blocked cat is the term used to refer to a cat with a urethral obstruction. This occurs when a cat is unable to urinate due to a blockage in the urethra (the structure responsible for conveying urine from the bladder to outside the body). This condition most often occurs in male cats and is considered an emergency.
Why are male cats more often affected by urethral obstruction?
Due to anatomical differences, this condition is more often seen in male cats than in females. Male cats have a narrower urethra compared to females, making them more likely to become obstructed.
Is ‘blocked cat’ an emergency?
Yes – a blocked cat is an emergency and is fatal if left untreated. Even though the clinical signs may seem minor at first, these cats can deteriorate very quickly.
When a cat is unable to urinate:
- The bladder continues to fill with urine, becoming overdistended and painful.
- Urine starts damming back into the kidneys, impairing the kidneys’ function and damaging them in the process.
- Waste products that are normally removed from the blood and excreted in the urine begin to build up in the bloodstream.
- Electrolyte imbalances develop.
- One of these electrolytes, potassium, can affect the heart and lead to life-threatening arrhythmias and cardiac arrest.
Because of this, prompt treatment is critical. If left untreated, this condition can become fatal within 24–72hours.
What causes a urethral obstruction?
Blockages can be caused by:
- mucous ‘plugs’ (common in cats, secondary to inflammation of the bladder)
- stones or crystals in the urine
- tumours or strictures (rare)
Are there any risk factors influencing the development of urethral obstruction?
Stress, stress and more stress. Stress plays a major role in many urinary conditions in cats. Stressors can include:
- a new environment
- new pets or cats in the area
- changes in the household (new family members, routine changes, etc.)
Diet can also play a role, particularly in the development of bladder stones. Certain diets, such as supermarket brands or non-veterinary kibble, can influence the urine pH levels. This alteration in urine pH may make it easier for some types of crystals or stones to form.
How do I know if my cat may be blocked?
Cats with a urethral obstruction may:
- strain to urinate (often mistaken for constipation)
- produce little to no urine
- pass blood-tinged urine
- cry or show signs of pain when trying to urinate
- urinate in abnormal places
- lick excessively at the genital area
- become lethargic and stop eating
- vomit (in more advanced cases)
It can be difficult to monitor urination habits in cats with outdoor access. In these cases, changes in appetite, energy levels or overall demeanour may be the first signs that something is wrong. If you notice these changes, it is recommended to take your cat to the vet for an assessment to catch a potential problem early.
How is urethral obstruction diagnosed?
The diagnosis of urethral obstruction is usually based on a history of straining to urinate, clinical signs, and a physical examination of your cat. On physical examination, the vet might find a hard, distended and painful bladder.
Blood tests may be performed to assess your cat’s kidney values/function, electrolyte levels as well as acid-base balance. These will help the vet to create a treatment plan tailored to your cat’s specific needs and to monitor their response to treatment while in hospital.
If the vet suspects that a bladder stone caused the blockage, radiographs (X-rays) may be taken to look for stones in the bladder or urethra. A urinalysis may also be performed to evaluate your cat’s urine and check for crystals or signs of infection. These diagnostics are not necessarily done immediately upon admission and are often performed once your cat has been stabilised.
How is urethral obstruction treated?
Treatment of a blocked cat focuses on stabilisation, relieving the obstruction as quickly as possible, and managing any complications that might occur.
1. Relieving the obstruction and decompressing the bladder
- The most important step is to remove the obstruction and allow the cat to urinate again.
- A urinary catheter is placed while the cat is sedated, after which the bladder is drained and flushed to remove any debris.
- The catheter is usually left in place for a few days.
In some cases, if a catheter cannot be placed, the vet may perform a cystocentesis (a procedure in which urine is collected directly from the bladder using a needle and syringe) to remove urine from the bladder and temporarily relieve pressure. If bladder stones are present, surgery may be required to remove the stones.
2. Fluid therapy
“The solution to pollution is dilution” – the same can be said about the treatment of metabolite/toxin build up in the bloodstream! Intravenous fluids are used to support circulation and help the kidneys recover, as well as to flush toxins from the bloodstream.
3. Correcting electrolyte imbalances
The kidneys are responsible for maintaining the correct electrolyte balance in the blood. With the kidneys not working optimally, dangerous electrolyte imbalances can develop. High potassium levels (hyperkalaemia) are especially concerning, as this can cause cardiac arrest and is often what causes mortalities in these cases. The vet will monitor and correct these imbalances as needed.
4. Pain relief and anti-inflammatories
These obstructions are very painful due to the inflammation. Your cat will receive appropriate pain relief and medication to reduce inflammation and urethral spasms.
5. Hospitalisation and monitoring
- Most cats are hospitalised for one to three days as monitoring is a big part of the treatment plan.
- During this time, the vet will repeat blood tests if needed, monitor urine production, and ensure that your cat is stable before discharge
- The urinary catheter is usually kept in place for up to three days or until the urine runs clear. Once removed, there is a risk of ‘re-blocking’, so close monitoring is essential to determine if another urinary catheter needs to be placed.
What happens after my cat is discharged? How can I prevent this from happening again?
At discharge the vet might send you home with monitoring instructions as well as medications such as anti-inflammatories and sometimes antibiotics or urinary supplements, depending on the underlying cause.
Long term management consists of dietary management, encouraging water intake and reducing stress at home.
Diet
- The vet may recommend a prescription urinary diet.
- These diets help support and improve urinary health and may reduce the risk of crystal formation.
Water intake
- Provide multiple water sources in your house so your cat has 24/7 access to fresh water.
- Consider providing different types of sources, like water fountains, and see what your cat prefers.
- Wet food can also help improve daily water intake.
Stress
- Stress is multifactorial and requires a multifactorial approach to manage it.
- Providing environmental enrichment, a consistent routine and safe spaces for your cat to use can help.
- The use of pheromone products may be beneficial to some cats and often can be purchased over the counter at local pet shops.
Unfortunately, some cats are prone to re-blocking, even after successful treatment and good post-hospitalisation management. This can occur days, months, or even years later. Careful at-home monitoring is important to catch any recurrence early and to allow for prompt treatment.
To reiterate, urethral obstruction is an emergency and early intervention and treatment are crucial for survival. The good news is that, with prompt intervention and proper long-term management, many cats go on to live happy, healthy lives.
If you are ever concerned that your cat may be blocked, it is always safest to seek veterinary care as soon as possible.
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