Any breed of horse or pony can be affected by inflammation in the muscles and joints. In many cases this inflammation or swelling is due to infections, injury and less commonly to congenital genetic conditions. In any horse with inflammation it is important to determine the cause of the swelling and heat in order to correct the problem and help prevent further occurrences.
A horse's body responds to pain or injury by flooding the area with fluids to prevent further injury and to supply red and white blood cells to the area to combat the infection and bacteria. This is all triggered by hormones and chemicals released by the injured or infected cells that trigger the production of three different compounds or hormones that react in different ways within the body. Prostacyclin is the first compound released, which results in the expansion or dilation of the blood vessels in the area of the injury or infection. This allows a greater amount of blood flow to the area to fight the infection and to supply nutrients to the damaged cells. Since there is more blood flow the area feels warmer, plus more fluids are in the injured or infected tissue resulting in the swelling. Later two other compounds, prostaglandin and thromboxane are released by the body, resulting in vasoconstriction and the formation of blood clots to help with isolation and healing in the area. In addition the prostoglandins stimulate the kidney filtering process and change the hypothalamus's regulation of the body temperature, resulting in low to high grade fevers.
While these systems are designed to help the body to heal, they can also be very problematic. In cases where the fever and swelling become barriers to healing it is necessary to use medications to help bring down the fever and allow the body to drain fluids from the infected or injured area. Vets may use a different type of medication based on the type of injury and other complications that may occur.
One of the most common treatments for inflammation in horses is a non-steroidal anti-inflammatory or NSAID. These drugs include aspirin, ketoprofen and dipyrone to name just a few. NSAIDs are all very weak acids that bind to the proteins in the blood and are carried to the injured area by the blood. Once there they act to block pain receptors and suppress the body's natural inflammatory responses thereby reducing swelling and fever. Some NSAIDs can be toxic so careful monitoring is required.
Corticosteriods may also be used in the treatment of inflammation in horses. They alter blood glucose levels by stimulating the adrenal glands to provide additional energy to the cells, but can also result in insulin and blood sugar regulation problems if incorrectly used long term. In addition they stimulate the production of white blood cells that are used to fight off infections in the body. It is important to note that corticosteriods are highly effective at treating the symptoms of inflammation, but they do not treat the cause. Corticosteriods are used for pain management and controlling the swelling, then the vet must address the cause of the problem. New research into the management of inflammation in horses is ongoing with many new products that are safe, easy to use and highly effective now readily available.