Like people, horses may be taken down by a bout with colitis. This condition can strike any horse, any time, and any place. Famous race and performance horses have struggled to win their fights with the disease and it can lead to other dire consequences such as laminitis.
Is it colic or colitis?
Famous race and performance horses have struggled to win their bouts with colitis and it can lead to other dire consequences such as laminitis.
Colitis is an inflammation of the tissues in the horse’s colon. The horse’s gut is a very specialized place, containing a variety of beneficial bacteria and microbes that help it extract nutrients from the grains and grasses it eats. It also plays a vital role in water absorption. However, when unwelcome bacteria or stress is introduced, bad things can happen.
“The equine gut is a shock organ,” says Dr. Peter Heidmann, an equine internal medicine specialist at Montana Equine in Three Forks, Mont., “meaning the end stageof lots of different inflammatory events can affect the gut.”
Unlike colic, an obstruction or twisting of the bowel that colitis is often mistaken for, colitis is an inflammation of the colon itself. “Colitis, instead of being a blockage, tends to be caused by an infection,” Heidmann says. “It’s a pretty darn common disease.” The infection can be caused by a variety of factors, including bacteria such as Clostridium difficile, E. coli, salmonella or Potomac Horse Fever.
According to Douglas Thal, DVM, DABVP, Thal Equine LLC, Santa Fe, N.M., the equine digestive tract is a complex and fragile system that is easily disrupted. One sign that the colon is disturbed is the development of diarrhea, from mild to severe—even life-threatening. Once colon health is disrupted, its ability to carry out the normal functions of digestion and absorption are critically affected.
"Serious colitis causes severe diarrhea, which accounts for huge water loss, and can cause rapid loss of fluid from the circulatory system," Thal says. "This leads to a vicious cycle of low blood pressure and reduced blood flow to vital organs and circulatory shock, which can quickly result in death if untreated."
Colitis disrupts the integrity of the mucosa. Once a horse is affected, the ability of its colon to absorb water and nutrients—the colon's normal function—is compromised. In addition, major shifts take place with respect to the bacterial population needed for normal gastrointestinal (GI) function.
GI inflammation can take several forms. It can occur as segmental disease, limited to one section of the GI tract, or as more diffuse, nonsegmental disease, says K. Gary Magdesian, DVM, DACVIM, DACVECC, DACVCP, professor at the University of California-Davis School of Veterinary Medicine. Magdesian notes that the illness is called:
- Colitis when restricted to the large colon
- Typhlocolitis if the cecum also is involved
- Enterocolitis if the small intestine is included
- Enteritis when it's limited to the small intestine
- Gastritis if the inflammation affects only the stomach
- Gastroenterocolitis if the entire GI tract is involved.
In general, the younger the horse, the more likely it is to have primarily small intestinal involvement. But even mature horses can have any of these forms, including diffuse disease, disease limited to the small intestine or disease limited to the large colon.
Regardless of the infecting agent, horses with colitis develop severe symptoms quickly and they begin to lose electrolytes and protein in their manure. When the colon is so inflammed that it cannot do its job re-absorbing electrolytes and needed protein, the horse's life is at risk and need the best in supportive care.
Colitis is a medical emergency and a veterinarian should be called any time that diarrhea affects the well-being of a horse. The veterinarian can detect the source, quickly treat dehydration and electrolyte imbalances, and prescribe remedies to help the horse recover from colitis.