Urinary Obstructions in Cats
Written by Small Door's medical experts
A urinary obstruction (UO) in cats, also known as a urethral obstruction or a blockage, is a life-threatening condition where the urinary tract becomes blocked. It’s predominantly seen in male cats, and requires emergency veterinary care. As a cat owner, make sure you’re familiar with the signs of a urinary obstruction, such as straining to urinate, so you can seek medical care immediately.
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A urinary obstruction occurs when the urethra (the tube that carries urine from the bladder out of the body) becomes blocked, meaning your cat cannot pass urine. It’s a medical emergency and if left untreated, the bladder will become overfull, which can lead to severe damage to the bladder and kidneys, and can be fatal in as little as 24 hours.
Symptoms that may indicate a urinary obstruction in cats include:
Unable to urinate, passing only a few drops of urine, straining, or frequently visiting the litter box. (It’s possible to misinterpret this for constipation, so always ask your veterinarian if you’re unsure.)
Blood in urine
Excessive licking of genitals or abdomen
Pain when the abdomen is touched
Aggression due to pain
Urinary obstructions in cats are extremely painful and mean they’re not able to pass urine. This leads to toxin buildup within the body and acute kidney injury (AKI) as the kidneys become progressively injured from pressure buildup and eventually start to fail. These toxins can also lead to electrolyte abnormalities, appetite loss, nausea, and vomiting.
As your cat’s potassium levels increase (known as hyperkalemia), they may experience a decrease in their heart rate as well as abnormal heart rhythms (arrhythmias), which can result in a fatal cardiac arrest, where the heart stops.
Cats with a urinary blockage may also have low blood pressure and are often dehydrated.
The most common cause of a urinary obstruction is when the urethra becomes blocked by mucus and inflammatory cells. Additional causes include bladder stones, urethral inflammation and spasms, narrowing or scarring of the urethra, as well as cancer. Cats who have a history of Feline Lower Urinary Tract Disease (FLUTD) are prone to urinary obstructions.
Some of the risk factors associated with the development of a urinary blockage include being fed a predominantly dry food diet, being overweight, anxiety and stress, and living in a multi-cat household. Common cat stressors include new people or pets in the household, competition for resources (such as food, toys, scratching posts and litter boxes) within the household, seeing other cats outside, construction or other loud noises, or changes in their environment, including moving furniture, changing litter box location or litter type.
A veterinarian can diagnose a urinary obstruction based on clinical signs as well as by feeling your cat’s bladder. When felt, the cat’s bladder is large and firm, and cannot be emptied with gentle pressure. It is usually painful when the abdomen is touched.
Once a blockage is confirmed, your veterinarian will typically conduct baseline blood work to check your cat’s kidney values and electrolyte levels, which will help determine the overall effect the blockage has had on their body.
Several other diagnostic tests will also be recommended to help determine the underlying cause and address any secondary concerns if needed. A urinalysis and urine culture is usually performed to check for crystals as well as a urinary tract infection (UTI). A radiograph (x-ray) or ultrasound of the bladder may be performed to rule out the presence of stones and check for any other abnormalities. Your veterinarian may also take your cat’s blood pressure or conduct an EKG (electrocardiogram) to check for abnormal heart rhythms, depending on the severity of the condition.
Cats with a complete urinary blockage require emergency medical care and will often need to be admitted to the hospital for several days. Once they’ve been stabilized if necessary, and your veterinarian has conducted initial diagnostic tests, treatment can begin to remove the blockage.
Your cat will be placed under sedation or anesthesia, and a urinary catheter will be placed via the urethra into the bladder to ‘flush out’ the obstruction. Depending on the severity of their condition, the catheter may need to remain in place for several days. It will help to make sure urine is able to leave the body while allowing time for the inflammation in the bladder and urinary tract to subside, as well as taking pressure off the kidneys and allowing them to heal. Your veterinarian will also use the catheter to monitor your cat’s urine output and assess the urine for blood clots and other debris.
In addition to the catheter, your veterinarian may recommend IV fluids to help flush out toxins from your cat’s body and to help rehydrate them. Your cat may also need pain medication, anti-nausea medication, and medication to relax the urinary tract.
During their time in the hospital, your veterinarian will monitor your cat’s kidney values and electrolytes with daily bloodwork. Once their values return to normal levels and their urine appears normal, the catheter can be removed. In most cases, it will remain in place for 48 to 72 hours. Once the catheter is removed, your cat will be monitored for several hours to make sure they can urinate on their own before they’re allowed to go home. Your veterinarian may prescribe medications to help manage pain and anxiety once your cat is back home, as well as urethral relaxants. In addition, a special urinary diet and/or antibiotics may be required.
If the cause of your cat’s blockage was bladder stones, your cat may require surgery to remove the stones, known as a cystotomy, or they may need a special diet to help break down the stones.
Is There a Cure for Urinary Obstructions in Cats?
If treated quickly enough, a urinary obstruction can be cured, but it does require aggressive medical care.
If your cat experiences multiple urinary blockages, your veterinarian may recommend a surgery called a perineal urethrostomy (PU) to help to avoid recurrent obstructions. In rare circumstances where an obstruction cannot be unblocked using the standard technique, a PU surgery may be required.
Is a Urinary Obstruction Contagious to Humans or Other Pets?
No. A urinary obstruction is not contagious to humans or other pets.
What is the Cost of Treating a Urinary Obstruction in Cats?
As urinary obstructions often require a prolonged hospital stay with diagnostic testing and procedures, they may cost several thousand dollars. If a cystotomy or PU surgery is required, the price can increase further. Long-term, the costs of this condition can add up, since it often recurs.
A prescription urinary diet may be recommended, which is more expensive than over-the-counter food, and long term medications are sometimes required, although these are not typically expensive. After an obstruction, your veterinarian may recommend follow up bloodwork and urine testing to make sure any kidney injuries have resolved, as well as any bladder inflammation or infections. Radiographs might be recommended to monitor for stone recurrence if the initial episode was caused by bladder stones. These additional tests can all add additional costs.
If treated promptly, cats can recover from a urinary blockage. However, if left untreated, this condition is fatal. After they’ve been unblocked, cats may unfortunately become re-blocked at any point after their catheter is removed. Some cats may experience another blockage a few hours or days after the catheter is removed, while others may re-block a few months or years later. It’s not possible to predict if and when this may occur, so it’s important to always monitor your cat for signs of another blockage.
If a urinary obstruction keeps recurring, your veterinarian may recommend a perineal urethrostomy surgery. During this surgery, the penis is removed and a wider urethral opening is created. This minimizes the risk of re-obstruction.
The most important thing you can do to help prevent urinary blockages is to increase your cat’s water intake. This means they have to urinate more frequently, and so their bladder is ‘flushed out’ on a more regular basis. You can help your cat to take in more water by feeding them a canned/wet food diet, by adding water or low sodium broth to dry food, introducing a water fountain (many cats prefer fresh, flowing water), or providing multiple drinking sources.
If your cat insists on eating only a dry diet, your veterinarian may recommend a prescription urinary diet, as they can help to encourage your cat to urinate more frequently. If they were diagnosed with urinary crystals or stones, your veterinarian may recommend a diet such as Royal Canin SO, Hill’s c/d, or Purina UR to help alter the pH of your cat’s urine, making it more difficult for crystals or stones to form. In these cases, wet, canned food is also preferred over the dry varieties.
Stress management is an important aspect of managing urinary issues in cats. As urinary problems are more prevalent in indoor-only cats, it is really important to provide plenty of environmental enrichment for their mental stimulation and to reduce stress. In multi-cat households, it’s also important to have enough feeding stations and litter boxes for all cats. If your cat feels stressed or rushed while using their litter box, this can contribute to urinary issues, so it’s important to follow best litter box practices, and ensure your cat is never antagonized by other pets while using the litter box. Cats who are very anxious might require long-term intervention via medication to lower their stress levels.
Weight loss in overweight cats can also help to reduce the risk of urinary obstructions, and cats with a history of urinary obstruction should have regular bloodwork and urine testing. Imaging such as radiographs or an ultrasound might be recommended if there is history of bladder stones.
Is there a vaccine for urinary obstructions?
No, there is no vaccine for urinary obstructions.
A urinary obstruction is an emergency condition that occurs predominantly in male cats, and particularly if they have a history of FLUTD. If treated quickly and with aggressive medical care, the prognosis is good, but if left untreated, it can be fatal in as little as 24 hours, so it’s essential to watch out for the symptoms of a blockage. If your cat seems to be having difficulty urinating, is making frequent trips to the litter box or displays any other concerning signs, you should take them to be checked by your veterinarian immediately. Blockages cannot always be prevented, but if your cat is predisposed to them, you should speak to your veterinarian about dietary changes, stress reduction, and weight loss.