We see lots of cats for bladder issues. Some of them are behavioral in nature, but a lot of them are caused by disease. The most common bladder or urinary diseases that we see, are bacterial urinary tract infection, crystalluria, bladder stones, interstitial cystitis, urethral plugs and urethral sphincter hypertonus. And of course, rare but cancer is always possible.
Bacterial urinary tract infection does happen, in spite of some claims that it doesn't. The most common diseases that we see associated with it are diabetes and chronic kidney disease. Normal healthy concentrated urine tends to be antibacterial and prevent bacterial colonization in the bladder from bacteria always found on the perineal skin and distal urethra. The diabetes results in sugar in the urine, which is like candy to bacteria. They grow like crazy. CKD can result in very dilute water urine, and at a certain point it becomes so watery that it is no longer antibacterial. Cats can also get secondary bacterial bladder infections from blood, crystals, or stones being present in the bladder. The blood can also make the urine less antibacterial, and the crystals and stones can cause bleeding in the lining of the bladder.
Treatment is always antibiotics, and if there is an underlying cause, treating that cause as well. The biggest concern is preventing the infection from spreading up to the kidneys. We will usually diagnose bacterial UTIs by looking at urine sediment under the microscope, and if we see an abnormally high amount of bacteria, or elevated white blood cells, then we may presumptively diagnose bacterial UTI. If in doubt, or if the UTI is not responding to antibiotics, then we may also culture it to see what bacteria grow, and what they will respond to.
Crystalluria. This happens when your cat's urine becomes too acidic or too alkaline. Normal urine pH is 6.2. Anything that affects that can result in crystals forming in the bladder. By far, the most common reason that we at All Feline see crystalluria is from diets that tend to alkalinize the urine. Now that doesn't mean that every cat that eats those will develop crystalluria. But some cats are more sensitive to the proportions of ingredients. If you want to know which diets we tend to see cause this most often, call us. Crystalluria can also develop from bacterial UTIs. The bacteria also tend to alkalinize as they proliferate. Certain metabolic diseases can also cause other types of crystals to develop in the urine.
Crystalluria hurts like crazy. Imagine have little shards of glass floating around in your bladder, and going through your urethra every time you urinate. Ouch. That is why a lot of cats will start going outside of the litter box. They not only associate it with pain, but they are trying to get your attention to help them. Maybe not the best method, but that is how they work. The crystals cut into the lining of the bladder as they float around resulting in bleeding into the urine.
The treatment for crystalluria is to figure out what type of crystals are present, which we can do by looking at a fresh urine sample under a microscope. Once we know what type they are, we can take steps to stop them from forming. Many times that just requires a diet change. In the meantime, we will also treat with pain medications, and if there is evidence of a secondary bacterial infection, we will also treat with antibiotics.
Bladder stones. These most often result from crystalluria where all the crystals clump together to form a stone, but we can also see bladder stones with no crystalluria present. If the bladder stone happens to be a struvite stone, we can actually get that to dissolve with a prescription urinary acidifying diet. All other stones need to be removed surgically. However, we cannot tell just by looking at an x-ray or ultrasound what the stone is made of. We can get a rough idea based on the size and shape of the stone, and the number of stones present, but we will some times just try the acidifying diet, and if we don't see any improvement after a month, then go in surgically to remove the stone. At that point we will send the stone into a lab to be analyzed so that we can prevent more from forming again.
Interstitial cystitis, also known as idiopathic cystitis. This is a fun one. There is no easy diagnosis for this other than doing a bladder biopsy, which we don't tend to jump to doing. Instead, we tend to diagnose interstitial cystitis by ruling out all other causes of blood or elevated white cells in the urine. Interstitial cystitis is actually a type of inflammatory disease that is caused by stress. When your cat's cortisol levels increase as a result of stress, this actually triggers an inflammatory process that results in inflammation in the lining of the bladder, which leads to blood and in some cases, lymphocytes which are a type of white blood cell building up in the urine. This is sadly very common, and very under diagnosed by many vets. Some cats will have only one flare up in their life, some will have flare ups every few months.
The treatment for this consists of anti-anxiety medications to decrease your cat's stress levels, pain medications and anti-inflammatories to reduce the pain and inflammation in your cat's bladder lining, antibiotics as needed for secondary bacterial infections, medications to help replenish the damaged lining of the bladder, diet changes to make the urine as bladder friendly as possible and sometimes even filtered water to minimize the minerals in the urine that can be irritating to a damaged bladder lining.
Urethral plugs. These are only an issue in male cats, they are life-threatening, and they are an emergency if they happen. Male cats have a urethra that narrows and bends before it finally empties. Because of this, they can develop urethral plugs that can consist of crystals, small stones, or even plugs of mucus. Once a plug forms, your cat can suddenly no longer urinate. Not only is this incredibly uncomfortable and painful (have you ever really had to use the restroom, but couldn't find one, and you were just dying from a full bladder for a few minutes to a few hours? Imagine not being able to go for a few days), but it quickly becomes life threatening. As the urine starts to back up in the kidneys, acute kidney failure starts which can cause weakness and vomiting. The most significant thing is that the body can no longer excrete potassium into the urine. The potassium starts to build up in the blood stream. After about 2-3 days of not being able to urinate, the potassium level gets so high that it starts to cause cardiac arrhythmias, and eventually, stops the heart. Even though the heart stopping doesn't hurt, can you imagine dying from not being able to urinate for 2-3 days. Agonizing. If you think your male cat is having problems urinating, even if it is , get them to a vet immediately!!! Maybe it is just painful urination from a bladder infection, but if they are truly blocked, they can die - would you wait if it was you?
We can almost always get the urethra unplugged and get the urine flowing again. The only exception is if a stone is really firmly wedged in the urethra, or if there is some other cause for the urethral obstruction such as cancer. Anything else, we can get them unblocked, although it can take time and lots of pain meds for your cat. If for any reason we can not get your cat unblocked, we will at the very least drain your cat's bladder using a syringe until we can fix the problem. We also listen to the heart and check blood work. If we suspect elevated potassium, we will give your cat insulin to drive the potassium out of the blood into the cells, and glucose to counteract the insulin. If there are signs of acute kidney failure, then we will also put your cat on an IV for 2-3 days to flush out the toxic enzymes. We will also leave a urinary catheter in place for a few days so that we can continually flush the bladder.
Once the life threatening obstruction is under control, the next step is to prevent it from happening again. If the obstruction was caused by a stone or crystals, then we may put your cat on a prescription diet for life to prevent stones or crystals from ever reforming. Yes, just changing to a different regular diet might also prevent the problem, but do you really want to take the chance of your cat blocking again? If the obstruction was caused by a mucus plug, then increasing your cat's daily fluid intake and a prescription diet will usually prevent reoccurrence. If the blockage was caused by urethral sphincter hypertonus, we may put your cat on lifelong drugs to relax the urethral sphincter.
As a last resort, a surgery called a perineal urethrostomy can be performed, which will basically make your cat urinate like a female. This surgery can have potential complications though, including an increased chance of bacterial UTIs, and as a worst case scenario, scarring shut at the surgery site. We very rarely perform this surgery at All Feline, as we can generally get the problem fixed with diet change and increasing fluid intake.
Urethral sphincter hypertonus. This happens when the muscles that relax to allow your cat to urinate don't relax. Your cat has to urinate, but they cannot relax the sphincter muscle that will allow them to go. In males, this can be a cause of urethral obstruction. In females, you may just see them going in and out of the litterbox frequently. There may not be any infection or inflammation present in the urine, but they can't fully empty their bladder when they are able to go, so they go much more frequently. This can also be caused by spinal nerve damage such as being hit by a car, or severe spondylosis of the spine, which is a type of arthritis of the spine.
The treatment for this consists of drugs to relax the urethral sphincter muscle, and in some cases, especially with spinal damage, drugs to increase the contractility of the bladder muscles. These are almost always lifetime treatments, if the urethral sphinter hypertonus is not temporary as a result of a UTI or urethral blockage.
Bladder cancer. Very rare in cats, thankfully, but almost identical to cancer in the kidneys. It is usually caused by either lymphoma or transitional cell carcinoma, so we will often treat presumptively with piroxicam in the hope that it is transitional cell carcinoma and so will respond to the piroxicam.