Infiltrative Colonic Disease in Horses

Infiltrative colonic disease may affect the entire intestine of your horse or could be limited to a small area. It is important to understand the symptoms of this disease vary greatly depending on the cause of the issues. Your horse may present in pain, with a loss of appetite, show weight loss, and experience diarrhea. Due to these symptoms being somewhat generalized it may be difficult to differentiate what type of stomach issues he may be dealing with.

Infiltrative colonic disease (ICD) in horses is defined by an infiltration of your horse’s intestinal wall caused by cell formation (plasma cells, eosinophils), neoplasia or scarring. This infiltration results in an inflammation of his stomach, dietary issues, absorption issues and more.

• Weight loss – One of the more common symptoms of ICD
• Colic – Abdominal pain in your horse that is severe 
• Lethargy – You may notice your horse appears to be tired and without energy
• Dependent edema – Fluid buildup in his stomach or his limbs
• Diarrhea – He may have loose stools 
• Hypoproteinemia – Upon evaluation by the veterinarian, your horse may be diagnosed with having low levels of protein in his blood 
• Depression – Your horse may suffer from depression and struggle to do his normal activities 

Types

There are multiple types of ICD and each one corresponds to a different part of the digestive tract. 

• Granulomatous Enteritis (GE)
• Lymphocytic-Plasmacytic Enterocolitis (LPE)
• Multisystemic Eosinophilic Epitheliotropic Disease (MEED)
• Eosinophilic Colitis (EC)
• Eosinophilic Enteritis (EE)
• Idiopathic Focal Eosinophilic Enteritis (IFEE)

While there is no known cause for any of the ICD conditions, there is some thought that some horses may have an abnormal reaction to bacteria, viruses, parasites, or a change in diet. These abnormal responses result in inflammation and thickening of the digestive tract and other problems. The common symptoms, possible risk factors and other information of each ICD category are:

Granulomatous Enteritis (GE)

• Impact young horses up to 4 years of age typically
• Anemia is found

Lymphocytic-Plasmacytic Enterocolitis (LPE) 

• Impacts horses of any breed, age or sex
• May be a precursor to lymphosarcoma

Multisystemic Eosinophilic Epitheliotropic Disease (MEED)

• Young horses and Standardbreds appear to have a higher risk and be predisposed to this type
• Dermatitis is a common symptom
• Respiratory symptoms are present
• Effects the large colon more than the small intestines

Eosinophilic Colitis (EC)

• Mostly impact young horses
• Presents as colic

Eosinophilic Enteritis (EE)

• Seems to affect young horses more so
• Causes colic

Idiopathic Focal Eosinophilic Enteritis (IFEE)

• Also appears to affect young horses 
• Causes colic

Diagnosing ICD is done by ruling out other possible causes for your horse’s symptoms. Your veterinarian will most likely want to perform a full physical exam and take blood work and samples of his fecal matter to test for possible parasites, illnesses, or toxins.

Once all other potential underlying causes are ruled out, the diagnosis is then made via biopsy from your horse’s intestines. This can be risky as many horses dealing with ICD are anemic so healing of their incision may be difficult and must be closely monitored. 

Other tests sometimes performed are camera and imaging tests to see if there is thickening and inflammation of the intestine or colon. This better helps your veterinarian to determine the cause of his ICD and can implicate possible treatment options as well.

Treatments for the stomach condition are limited to corticosteroids, diet changes and surgery due to there being very limited ideas as to what causes these conditions. Some of the dietary management that may be recommended are probiotics, vegetable oil, pelleted feed, and beet pulp. 

Most horses are treated with a medical management approach for their symptoms first, though surgery may be required if their intestines are beyond repair at that time. The surgery may be performed to remove the part of their intestine that is too damaged to remain.

Unfortunately, these conditions all have poor to fair long term prognosis. Most treatment is based on reducing symptoms and helping your horse to be comfortable. Full recovery is not likely, however, some changes can be made to help your horse live a better life.

Providing him with smaller and frequent meals made up of high energy and high quality foods can help. Increasing protein and high fibers foods may also help him, a pelleted diet that has all necessary nutrients will be good for him as well. Ongoing appointments and checkups with your veterinarian will be necessary to ensure your horse is doing well and does not have continued side effects because of his stomach issues.