Colic is a general term that is used to describe abdominal pain. This pain can be relatively mild or it can be extremely violent. It can have a slow, insidious onset or it can occur suddenly. The reasons for the wide variety of presentations are directly due to the different causes of the pain. The signs of colic occur with excessive gas in the intestines, increased spasms of the intestines (cramps), indigestion, gastric ulcerations, anatomical displacement of different segments of the bowel, and blockage of the normal blood supply to parts of the intestine. In the process of diagnosing the underlying problem, one collects many clues. The art of dealing with colics is to assimilate all the clues to attempt to unravel the puzzle and come up with the appropriate therapy for the horse.
A complete history is an important aspect in the diagnosis of equine colic. Information should include the animal’s diet, environment, deworming history, current workload and previous medical history. The more specific questions concerning this particular colic should incorporate the duration of the colic, last time the animal was fed, any recent changes in the feed or work level, if the animal experienced a recent trauma, if there a chance that the animal has ingested a foreign body, and if the animal is pregnant. A history of being off feed for a few days, decreased fecal output, and exhibiting mild abdominal pain would lead your veterinarian in the diagnosis of a simple obstruction. A history of an acute onset of severe, violent pain with rolling and pawing would lead to a diagnosis of a more serious problem such as an intestinal strangulating obstruction.
Farms that have colic as a more frequent problem have certain risk factors that need to be evaluated. Some of the factors include the following: inadequate parasite control, moldy hay or grain, inadequate roughage availability, sandy soil for horses fed on the ground, lack of water, and lack of stable help to keep the horses on a set feeding and watering schedule.
During an exam, listening to the abdomen for gut sounds helps to determine whether there may be a gas cap.
When beginning your physical examination of the colicky horse, one must first observe the attitude of the horse. Is the animal alert or depressed? How severe is the pain? Is it intermittent or continuous? What is the body condition of the horse? Is it thin, fat, or normal?
After these parameters are evaluated, then a temperature, pulse and respiratory rate should be taken. The presence of a fever may indicate an infectious process. Heart rates generally increase with pain and shock. Heart rates over 70 have a more guarded prognosis. Increased respiratory rates may be due to pain or compression of the thorax secondary to abdominal distension.
The horse’s gums should be evaluated for color and capillary refill time. The normal color of a horse’s gums is pink. Capillary refill time is the time it takes the gums to return to a pink color after you have blanched it out with finger pressure. This is approximately two seconds in the normal horse. In the horse that is going into shock, the mucous membrane color can range from dark pink to purple, with a capillary refill time of more than three seconds.
Auscultation of the abdomen with a stethoscope is important to determine the presence of intestinal sounds. We divide the abdomen into four quadrants, upper and lower left, and upper and lower right. In the normal animal there should be sounds in all of these areas. Percussion of the abdomen, especially the upper right side, may reveal a gas cap.
Other parameters that your veterinarian may do would include the passing of a nasogastric tube and a rectal examination. The nasogastric tube is a hollow soft plastic tube that is passed up the nasal passages, down the esophagus and into the stomach. If there is excessive gas in the stomach, a gush of odiferous air may be released. Sometimes it is important to drain the stomach of any excess fluid that has accumulated. This is accomplished by trying to create a siphon. The amount of fluid that is refluxed and its color are important clues to the cause of the problem.
The rectal examination is important for examining the internal abdomen. Your veterinarian is familiar with the normal internal anatomy and is feeling for bowel that is abnormally positioned or increased in size. The rectal is very helpful in most cases when determining whether the problem can be treated medically or surgically.
In cases that are more difficult to diagnose, additional tests can be done. A complete blood count and a serum chemistry profile can be use to assess the infectious and metabolic status of the horse. An abdominocentesis (a procedure where a needle or blunt cannula are inserted through the abdominal wall to collect a sample of the fluid that is in the abdomen) will help to decide whether there is compromised bowel. In colics due to twists or strangulation of the blood supply to a part of the intestine, the character of the fluid surrounding the intestines changes. The protein content and the white blood cells usually increase. A reddish tinge to the fluid indicates red cell leakage from the blood vessels.
X-rays of the adult horse’s abdomen is difficult due to its size and density. In cases where an intestinal stone or enterolith are suspected, x-rays using a powerful machine may be beneficial. Foal abdomens are fairly easy to radiograph.
Gastric ulcers are being diagnosed more frequently in the last few years. A definitive diagnosis can be made using a two-meter long endoscope. The horse is starved for 24-48 hours in order to empty the stomach. Even so, there is often ingesta still present obscuring some part of the stomach wall.
Post-operation home care consisting of stall rest, hand-walking, and pasture rest is pertinent to the healing of the horse’s belly wall.
Once the diagnostic tests are completed it is time to assess the all the pieces of the puzzle to determine whether the best treatment is medical or surgical. Surgical indications are uncontrollable pain, large amounts of gastric reflux, distension of the small or large intestine on rectal exam, abnormal peritoneal fluid, and the absence of gastrointestinal sounds. If the animal is to go to surgery, then it must first be stabilized. This means that if the animal is in shock or dehydrated, then large quantities of intravenous fluids should be given. Antibiotics are usually started before the surgery begins. Strangulating lipomas, enterolith, colon and small intestinal volvulus, nephrosplenic ligament entrapment, and intussusception are some of the more surgical-type cases. Surgery can take from two to four hours to correct the abnormality.
The post-operative care is critical to the successful outcome of these animals. They may require intensive care and hourly treatments for the first two to three days. If all proceeds well, the horses can be discharged at 10-12 days after the surgery. The home care consists of one month of stall rest, one month of hand walking and small paddock, and one month of pasture rest. This gives the belly wall time to regain most of its strength before the horse is asked to work again.
Gastric ulcers, impactions, anterior enteritis, colitis, and gaseous and spasmodic colics are best treated medically. Treatment depends on the specific problem. Gastric ulcers are treated with anti-ulcer drugs. Impactions generally receive stool softeners, such as mineral oil, and IV fluids. Anterior enteritis and colitis require intensive care and large amounts of IV fluids. Gaseous and spasmodic colics respond to analgesics.
Prognosis for life and return to use depends on the severity of the disease and the response of that disease to therapy. One researcher suggested using the physical signs below to prognosticate on the survival of equine colics.
GOOD GUARDED POOR
Heart Rate 40-60 bpm 60-100 bpm >100 bpm
Mucous membranes Pink Red Purple
Capillary Refill 1–2 Secs 3–4 secs > 4 secs
PCV 35–45% 45-65% > 6.5%
Peritoneal Protein <2.5 2.5 – 4.5 >4.5
- White, NA. The Equine Acute Abdomen, pp. 102-147.
Article by Dr. Mary Rose Paradis, faculty emeritus at Cummings School of Veterinary Medicine