Endotoxemia in Horses
By: Dr. Lydia Gray
Endotoxemia in horses is a serious, body-wide medical condition that requires prompt veterinary diagnosis and treatment to prevent grave, even fatal results.
What is Endotoxemia?Endotoxin is a part of the cell wall of certain bacteria (such as Salmonella and E. coli) that is released when these bacteria die, usually in the digestive tract. Normally, a healthy intestinal barrier along with a well-functioning immune system prevents endotoxin from entering the bloodstream, a condition called endotoxemia. However, when the body’s defense systems are overwhelmed by a large amount of endotoxin released from a massive bacterial die-off or when the enzymes, antibodies, and white blood cells that serve as a second layer of defense fail, endotoxemia can occur. Endotoxemia that is untreated or does not respond to treatment can lead to shock, a life-threatening medical condition that occurs when the circulatory system shuts down in response to trauma or illness.
Causes in Horses
Endotoxemia usually occurs as a result of another illness, and these illnesses can be divided into two categories: intestinal events and non-intestinal events. By far the most common cause of endotoxemia in adult horses, intestinal events such as colic or colitis cause a break in the intestinal barrier and permit endotoxin to leak into the bloodstream. Non-intestinal events that can result in the release of endotoxins into the bloodstream include a bacterial infection in the blood (septicemia), retained placenta in mares post-foaling, and respiratory disease such as pneumonia.
Rolling and repeatedly lying down and getting up are two signs that your horse could be experiencing colic.
Signs and Symptoms
Diagnosis & Treatment
Treatment should be started right away in order for the horse to have the best chance of recovery, and involves:
- Eliminating the source of endotoxin by treating the underlying illness such as colic, respiratory disease, a reproductive infection, or other source of bacteria
- Neutralizing any endotoxin already in the blood
- Administering non-steroidal anti-inflammatory drugs (NSAIDs) to block inflammatory mediators
- Providing intravenous (IV) fluids to support the circulatory system
How to Prevent Endotoxemia in Horses
- Make gradual feed changes (hay as well as grain)
- Avoid suddenly or abruptly introducing a new foodstuff into a horse’s diet
- Feed grain in multiple small meals rather than one large meal
- Ensure the horse receives plenty of roughage by feeding 1.5-2% of the horse’s body weight in hay (15-20 pounds for a 1000 pound horse)
- Practice good hygiene around and between horses, maintaining strict quarantine protocols to limit exposure