Your veterinarian can diagnose most urinary system problems by taking a history of how your horse has acted in the days prior to becoming sick, performing a physical examination, and performing tests on the horse’s blood and urine. The history that your veterinarian takes might include information regarding changes in how much water your horse drinks, how often it urinates, how much urine it produces, how the urine looks, and how your horse behaves. Your veterinarian will also need information about what medications your horse has taken or is currently taking, your horse’s appetite, diet, changes in body weight, and previous illnesses or injuries.
There are many tests a veterinarian might perform in the case of a urinary disorder. These include blood tests, blood pressure measurement, urinalysis, x-rays, contrast x-rays (tests in which a special dye is given to outline the urinary tract on the x-ray), ultrasonography, biopsies, and endoscopic evaluation of the urethra and bladder.
Urinalysis is a laboratory test that evaluates urine. It is one of the most important tools a veterinarian can use to diagnose urinary tract problems. Many tests are performed as part of a urinalysis. Physical examination of the urine includes noting the color and cloudiness, if any, and measuring the pH (to determine how acidic or alkaline the urine is) and urine specific gravity (which indicates of how concentrated the urine sample is). Chemical evaluation of the urine follows with tests for the presence of substances in the urine, such as sugar (glucose), ketones (a byproduct of the fat metabolism), bilirubin (a pigment produced by the liver), blood, and protein. Finally, urine sediment (prepared by centrifuging urine) is examined under a microscope to look for red blood cells, white blood cells, other cells, bacteria, and crystals.
Endoscopic evaluation is another valuable source of diagnostic information for a veterinarian. A small flexible tube with a camera located at its tip is inserted through the horse’s urethra and can be used to visualize the urethra and sometimes the bladder. This provides a good way to identify problems such as obstructions of the urethra, tumors, or malformations.