Phenylephrine for Colic

Equine gastrointestinal pain or conditions causing abdominal pain are known as colic. However, colic is a clinical sign, not a diagnosis. There are many causes of colic in horses but most are due to colonic disturbances. Some forms of colic can be fatal without treatment. Within the domesticated horse population, colic is the primary cause of premature death. Left dorsal displacement is one form of colic; phenylephrine is used to treat it.

Causes
- Ingesting too much dirt or sand can cause gastrointestinal problems.
  
  One form of colic referred to as impaction colic is caused by a variety of substances blocking the gastrointestinal tract. Ingested sand and dirt accumulates and irritates the bowel lining causing diarrhea and inflammation. Parasites or undigested food can also cause blockage and rupture of the small intestine. Ulcers, tumors, left or right dorsal displacement of the bowel tract or a twisted intestine or part of the colon can all lead to colic. A twist in the intestine also known as torsion is extremely painful, causes tissue death and requires emergency surgery.
Symptoms
- Looking back at, biting or nipping at the stomach area indicates gastrointestinal discomfort. Pawing, scraping, stretching, pacing or looking back at the flank and stomach area are common signs. Lying down and getting back up repeatedly along with rolling should be prohibited to prevent further damage. A horse in gastric distress may groan, salivate excessively and make frequent attempts to urinate. There may be little or no fecal output and an increase in heart rate.
Left Dorsal Displacement
- Surgery is required for severe cases of colic.
  
  Left dorsal displacement occurs when the left dorsal colon is trapped above the spleen and the nephrosplenic ligament. The nephrosplenic ligament joins the spleen to the left kidney. If the large intestine moves between the spleen and body wall, it becomes trapped over the ligament. This form of colic may require surgery.
Diagnosis
- A rectal examination may detect a displacement.
  
  A medical professional is needed to diagnose left dorsal displacement. A rectal examination can be used to palpate or feel internally for the displacement. Or an ultrasound machine can be used to visually detect the problem.
Treatment
- Exercise alone under veterinary supervision may correct the problem. Phenylephrine can be used in combination with exercise as well. Phenylephrine is a synthetic compound related to epinephrine. It is used as a vasoconstrictor (constriction of blood vessels). A rolling procedure is another method of treatment performed under anesthesia and in conjunction with phenylephrine. If dorsal displacement is severe enough or not corrected with exercise or rolling with phenylephrine, surgery is required.