Cystitis is inflammation of the bladder. The disease is usually caused by bacteria that reach the bladder from the lower urinary or genital tract, descend from infected kidneys or spread via bloodstream. Cystitis is more frequent in female dogs, but more serious in males. This is because the female urethra is wide and seldom becomes blocked with stones, whereas in the male the urethra cannot dilate as much and readily becomes blocked. A number of factors predispose a dog to cystitis, including:
- Urine retention due to narrowing of the urethra from calculi (stones), trauma, or tumors. Bacteria grow more rapidly in urine which is retained or stagnant.
- Urine retention due to damage to the nerve supply to the bladder from the spinal cord lesions such as slipped discs, infections, or tumors;
- Urine retention due to congenital defects of the bladder;
- Urine retention in dogs forced to hold urine for long periods.
- Deficiencies of fluids and vitamins.
- Diabetes mellitus or other causes of glucose in the urine, resulting in a good medium for bacterial growth;
- Trauma to the bladder from accidents.
The signs of the cystitis are increased frequency of urination, sometimes with evidence of straining or pain. The urine may be bloody, particularly the urine expelled at the end of urination. While actual blood is not always seen, in most cases the urine has a pinkish tinge. Otherwise, the dog is usually alert, has normal appetite and temperature. If the dog cannot urinate at all due to obstruction of the urethra or nerve damage to the bladder, then signs of uremia will be evident, and immediate treatment is essential. Analysis of the dog's urine will confirm the diagnosis, and if bacteria are evident, culture and sensitivity testing will be recommended in most cases to determine the antibiotics to use. If the primary cause of the cystitis cannot be determined, x-rays and even a biopsy may be required. Another technique helpful in diagnosing the cause of cystitis is cytoscopy. Because most cystitis cases are caused by bacterial infections, antibiotics are effective in clearing them up. Some cases will require long-term treatment. A number of different antibiotics may be tried before an effective one is found. In severe cases, antispasmotics, pain relievers, and urinary antiseptics are used initially to relieve the signs. To reduce the bacterial load in the urine, urinary acidifiers, such as ammonium chloride, methionine, mandelic acid, and vitamin C, are given. To prevent urinary stagnation, the dog owners should salt the dog's food, as this leads to increased drinking and increased urination, both of which help to keep the bladder flushed out. The dog with cystitis should never be allowed to hold urine, but should have free access to the outdoors.