Cystitis in Horses

By PetMD Editorial on Nov. 10, 2011

Bladder Inflammation in Horses

Cystitis, though typically uncommon in horses, is inflammation in the bladder. It is not often outwardly apparent that the bladder is inflamed, but there are other signs of cystitis that may be apparent. Some of the more obvious signs are excessive urination, excessive posturing to urinate, blood in the urine, or dribbling of urine without full voiding of the bladder. Cystitis tends to affect mares more so than stallions.

Symptoms and Types

  • Increase in the frequency of urination
  • Poor production of urine
  • Painful or uncomfortable urination
  • Unusual urine consistency or appearance (sometimes difficult to interpret, since normal horse urine contains large amounts of mucus and sediment):
    • Thick, cloudy urine
    • Bloody urine
    • Pus in urine
    • Blood clots in urine
    • Particles in urine


Although rare, cystitis is commonly caused by bacterial infection, be it from a urinary tract infection (UTI) that has progressed upwards, a kidney infection that has progressed downwards, or even infection in the blood (septicemia).

In some instances, if an injury has occurred, such as when the bladder or urethra is damaged in the course of a mare birthing a foal, cystitis may occur as a secondary condition to that injury. As a result of an injury to the bladder, the muscles of the bladder are not able to efficiently void urine that passes through it, resulting in sediment settling on the floor of the bladder and consequently, to inflammation of the bladder lining. Other causes include the presence of bladder stones, cancer in the bladder, or bladder paralysis secondary to a neurological condition.


You will need to give a thorough history of your horse's health and onset of symptoms to your veterinarian. The history you provide may give your veterinarian clues as to which organs are causing secondary symptoms are that are also being affected. The kidney, for example, may also be under duress, either as a result of the bladder inflammation, or concurrently. A complete blood count will be conducted, along with a urinalysis. An increased number of white and red blood cells in the urine is a clear indication of infection or inflammation of the bladder organ.

An internal examination is usually required, and this can be performed diagnostically by endoscopy, which uses a slender tube with an attached camera that can be inserted into the body. In this case, the endoscopic tool is a cystoscope. This will be inserted into the urethra and guided through the urinary tract into the bladder.

An analysis of the sediment in the bladder will also need to be done, which will necessitate a sample being taken from the bladder. This can be done by insertion of a urinary catheter. The fluid obtained can then be cultured and analyzed. In some cases, the horse may need to be tranquilized before a catheter can be inserted.



Treatment varies on a case by case basis when it comes to cystitis and according to the cause. Since the condition may be caused by more than one thing, the underlying cause must be resolved before the cystitis can be cured. This means that if the bladder inflammation is due to an underlying vaginal infection, the vaginal infection must be treated before the cystitis will go away without recurrence.

Once the primary cause of the cystitis has been removed, antibacterial and anti-inflammatory drugs can be used to treat the cystitis itself and relieve the horse of the symptoms. Some horses will repeatedly succumb to bladder infections. For these animals, a long course of antibiotics (for four to six weeks) may be warranted.

Living and Management

In many cases, cystitis is an issue that sneaks up on the horse and owner. Fortunately, it is relatively rare and in most cases can be treated once it has been properly diagnosed by an equine veterinary professional.

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