The bladder is a hollow, muscular organ that stores urine until it is passed out of the body (urination). It is part of the urinary system which is made up of two kidneys which filter waste products, which are excreted as urine, two ureters, which are tubes that pass urine from the kidneys to the bladder and the bladder.
Bladder problems are a common health problem in cats. There are several disorders that can affect the cat's bladder. These include:
What are the symptoms of bladder problems in cats?
A lot of bladder disorders have similar symptoms. These may include:
- Frequent urination (often only a few drops coming out at a time)
- Inappropriate urination (urinating outside the litter tray)
- Straining to urinate
- Painful urination
- Blood in urine (hematuria)
- Tense, painful abdomen
- Abdominal distension
Bladder tumours are rare in cats. There are several types of bladder tumour, the most common type of malignant tumour is transitional cell carcinoma (TCC)", and leiomyoma is the most common benign type. 
Diagnosis of bladder cancer may include:
- Complete blood count and serum biochemical profile to determine the overall health of the cat.
- Complete physical examination, including a rectal exam.
- Contrast X-Ray.
- Cystoscopy and biopsy.
- V-BTA test to detect antibodies in the urine against tumour antigens.
- Urine cytology (inspection of the urine under a microscope for the presence of abnormal cells).
Treatment involves surgical removal of the tumour if it is in a favourable location. Other treatments may include;
- Chemotherapy/radiation therapy
- Non-steroidal anti-inflammatory drug (piroxicam) may be of benefit to some cats with bladder cancer.
Bladder stones (uroliths) struvite or calcium oxalate are the most common form of bladder stones. Your veterinarian will be able to perform an ultrasound or x-ray to detect urinary stones in your cat. Bladder stones can lead to difficulty urinating and progress to a complete blockage. This is a life threatening situation which requires URGENT veterinary attention.
Depending on the type of stone, it is possible to prescribe a stone-dissolving diet. This appears to have worked well for struvite crystals, but not for calcium oxalate crystals. Surgical removal of the stones is another treatment option.
If your cat is completely blocked then your veterinarian may extract urine by placing a syringe through the abdomen and directly into the bladder and draw our the urine. This is a fast and effective way of emptying out the bladder in an emergency situation. Alternatively, he may choose to catheterise the cat immediately. See below for info on catheterisation.
Catheterisation: This is the system by which a catheterisation needle is inserted into what is called the Cephalic vein. This vein is located in one of the front legs of the cat. After the intravenous needle is placed in the front leg of the cat it is wrapped. A urinary catheter is also placed in the cat’s urethra. This helps re-hydrate the affected cat and also helps flush out small uroliths. Catheterisation on a cat takes place while the cat is under anaesthesia.
Read more about bladder stones (urolithiasis) in cats here.
Cystitis is defined as inflammation of the bladder. It may precede or be secondary to urolithiasis (stones in the urinary tract). 
There are several possible causes including;
- Idiopathic (no known cause)
- Bacterial infection
- Urinary crystals and stones
Treatment for cystitis includes;
- Increasing water consumption
- Switching to wet food
- Try to feed a diet which keeps the urine pH below 6.5. Unfortunately, long term use of an acidifying does carry some risks, one of which is the increased chances of developing calcium oxalate urolithiasis.
- Antibiotics: This form of treatment is used for mild cases of cystitis. The decision to prescribe antibiotics to a cat who is affected by cystitis depends upon the severity of the case. Most cases of cystitis resolve themselves within 5 days. However, since cystitis has been known to cause severe pain and damage in many cats, it is better to be safe than sorry. Antibiotics can help in some cases.
- Medications: Amitriptyline, which is an antidepressant and Analgesia (painkillers) are two examples of medications which may help a cat with cystitis.
For more information on cystitis, read here.
The ruptured bladder can be caused by trauma (car accident, high-rise syndrome), urinary obstruction, bladder cancer. In addition to the typical bladder diseases symptoms, a cat with a ruptured bladder may display the following symptoms;
Diagnosis of a ruptured bladder may include;
- Contrast x-ray
Surgical repair of the bladder is the method of treatment.
 Cat Health Encyclopedia-Edited by Dr Lowell Ackerman. Page 244.