Treatment of Visceral Pain in Horses

are approximately 100 conditions that result in abdominal pain in the horse, but the most common sources are the small and large intestine, hence the term “colic” most typically refers to gastrointestinal pain. Visceral pain may be acute, chronic, or recurrent in fashion, and some individuals may experience a combination of these manifestations. The cause of visceral pain may be organic (identifiable structural change in an organ) or dysfunctional (an abnormal change in organ function without identifiable pathologic changes). 2 Irritable bowel syndrome (IBS) in humans is an example of a dysfunctional disease that may affect up to 25% of the population 2 ; whether similar syndromes exist in horses is less clear, but is considered plausible. 3,4 Ischemia, inflammation, muscle contraction (spasm) or distension may be the primary underlying cause of pain, and identifying which of these is responsible for the patient’s discomfort is important for directing therapy. Considering the number of internal organs, it is not surprising that visceral pain is common in horses; however, it presents a challenge to the clinician because it can be difficult to make a definitive diagnosis. Ideally treatment is aimed at addressing the underlying pathology, but is often symptomatic with a primary focus on relieving pain; the latter is the focus of this article. Although treatment options for visceral pain have expanded in recent years, they remain suboptimal. In horses, the small and large intestines are the most prevalent