Equine Urinary Tract Disorders
Healthy adult horses seem to have a natural resistance to disorders of the urinary tract, but when problems in the renal system do occur, they are serious and must be dealt with promptly. Urinary tract infections (UTIs) are more likely to affect mares and foals. Mares are susceptible to lower urinary tract infections because their urethras are shorter than those of male horses and so can more easily transport bacteria to the bladder, resulting in cystitis. Foals, especially newborns, are also susceptible to UTIs.
Risk Factors for UTIs in Horses
Certain horses are at greater risk of developing urinary tract infections, most commonly bacterial cystitis. In addition to the increased risk assigned to mares and foals, horses are more likely to develop a UTI if they are geriatric or if they:
- Have an anatomical abnormality of the urinary tract
- Have overly dilute urine
- Have diabetes or another underlying disease
- Have a compromised immune system
- Have a blockage in the urinary tract
- Have chronic vaginitis
- Have a genetic predisposition to stone formation
Equine cystitis can also occasionally be the result of nerve damage or an adverse reaction to medication.
Symptoms of UTIs in Horses
Infections of the urinary tract are painful and debilitating. Symptoms of the disorder vary from mild to severe. It is always best to be aware of early signs of discomfort in the horse so a possible infection can be diagnosed and treated promptly. Symptoms of UTIs include:
- Frequent urination
- Incontinence, particularly dribbling
- Urine scalding
- Difficult or painful urination
- Blood in the urine, especially after exercise
- Depression or lethargy
In cases where nerve damage is causing the cystitis, there may be other neurological symptoms present, such as paralysis of the anus or tail.
Diagnosis of UTIs in Horses
In order to diagnose a urinary tract infection, a urine sample must be obtained for urinalysis and a urine culture. The culture will hopefully determine precisely which bacteria are causing the infection so they can be targeted with the correct antibiotic. Blood tests are usual as well. If other urinary tract conditions are suspected, ultrasound and MRI scans may also be necessary.
When bladder stones are diagnosed as the cause of the problem and are surgically removed, they are typically analyzed for chemical content. This is helpful in determining which minerals in the environment may be leading to the production of stones. It is possible that changing the horse's feed or water source may prevent the problem from recurring.
Treatment of UTIs in Horses
Bacterial cystitis is treated with the administration of antibiotics. If an underlying disease condition, such as diabetes, is detected, it must be treated as well. If stones, polyps or tumors are found, surgical intervention may be necessary.
Complications of UTIs in Horses
Some complications of urinary infections are uncomfortable and troublesome, but not particularly serious. In foals and mares, treatment with antibiotics for UTIs may result in fungal infections of the lower urinary tract or the vagina. Such infections are usually treated successfully with antifungal medications. Another possible complication of UTIs in horses is that, while bladder stones may be the cause of infection, they may also be the result, that is, a horse with persistent bladder infections may be prone to producing stones that make future infections more likely.
While most UTIs are relatively mild and easily treated, some cases present severe, even life-threatening, complications. Generally speaking, urinary disorders become more serious as they make their way up the urinary tract. Once the kidneys are involved, symptoms may become more severe and more difficult to treat, possibly resulting in kidney failure. If stones or other obstructions are not removed in a timely fashion, it may become impossible for the horse to pass urine or its bladder may rupture, either of which can prove fatal.
Symptoms that may indicate kidney infection (pyelonephritis) may include:
- Excessive thirst as well as excessive urination
- Pain in the sides
- General malaise
- Ulcers on the mouth or tongue
- Edema of the legs
- Ascites (swelling of the abdomen)
Kidney infections do not always show up in blood and urine tests. For proper diagnosis, X-rays, ultrasound or MRI scans may be needed. The treatment for kidney infections includes the administration of intravenous fluids and antibiotics. In severe cases, a kidney may require surgical removal.