You are up in the middle of the night. Your horse is restless and you are endlessly walking him up and down the barn isle way to help soothe his discomfort. Colic. Such as simple word, but yet so many different presentations in the horse with some cases resolving easily, while other horses require intensive levels of care. What causes colic in the horse? What options are available for better management and possibly for prevention? Is there a better way?
Colic simply implies abdominal discomfort or belly pain in the horse. Most owners usually interpret this as referring to intestinal pain, but this is not always the case. There are other organs in the abdominal cavity that can create pain, which then equates to ‘colic’ like symptoms. Other common offenders include liver disease, pancreatic conditions, kidney concerns, and urogenital conditions. These are all possibilities, but for the purposes of this article, we will focus on gastrointestinal causes.
The Origin of Pain with Colic in the Horse
There are numerous intestinal related causes of colic pain in the horse, and as mentioned in part one of this article, the main reason for pain development is due to distension or swelling of a piece of intestine. This distension can be due to gas, fluid, or food stuff accumulation. The reason for the accumulation is usually due to some form of blockage to normal flow. Think of it as being one of those cylindrical balloons that talented people make animal figures out of. Now, imagine that one end has a hose feeding continuous air into it, while the other end has a relief valve letting pressure off. Air comes in and air goes out. Next, twist a knot into the center of that balloon. What happens? The air continues to come in, but it is not exiting. Instead, the air or gas accumulates, and the balloon begins to swell. This swelling is what creates the discomfort and pain associated with colic in the horse.
The most common forms of colic in the horse were mentioned and listed in the first part of this article. No matter where the problem comes from, the specific location in the gastrointestinal tract, the ultimate problem is gas, fluid, or food stuff accumulation. This then creates the distension and pain.
The ultimate question comes as to whether or not the pipes can be unblocked, and re-establish normal flow? This is then dependent on the severity of the lesion present.
Typical Management of Colic in the Horse
The traditional management of colic in the horse includes a few tiers of therapy, focusing on specific problems that may present in that patient. These items are listed in priority, but not all are addressed in each individual horse patient.
- Pain management
- Nasogastric tube and reflux
- Rehydration (oral or IV fluid therapy)
- Management of infection or endotoxemia
The physical exam and status of the equine patient, as well as the response to first line therapy options, dictates the steps that we take as veterinarians.
Pain Management in the Horse with Colic
In most cases of colic, no matter the underlying condition, pain is our number one enemy and the first thing that must be addressed in all patients. The pain is created by the distension, which can be mild or severe in intensity. The pain which is felt by the patient can then also feed back into their clinical problem, meaning that the pain can further shut down normal movement or peristalsis of the gastrointestinal tract. It can become a vicious cycle of events, thus pain is our number one focus.
Common pain medications used to manage colic in the horse include:
- Non-steroidal pain medication (flunixen meglumine)
- Sedative medications (xylazine, detomidine)
- Narcotic pain medications (butorphanol, morphine, ketamine)
Generally, most cases of colic in the horse will be given at least one if not multiple injections of a NSAID medication with flunixen meglumine being the drug of choice. Flunixen meglumine (Banamine®) can be very helpful to reduce low to moderate levels of discomfort and in addition, this medication does appear to reduce the effects of endotoxin in the blood stream. However, not all horses respond to NSAIDs, as their pain level is too intense.
In the more intense or painful case of colic in the horse, they may require administration of a sedative medication, often combined with a mild narcotic. These medications can help to resolve or control higher levels of discomfort but do come with some side effects, mainly being decreased normal movement of the gastrointestinal tract. This can further add to the problem because when movement is reduced, gas and fluid can begin to accumulate, thus creating more distension.
Now, with all of this pain medication talk, you have to keep in mind the level of colic pain that is present in that specific patient and the cause.
A high percentage of equine colic cases are associated with gas accumulation, termed ‘flatulent colics’. In these cases, the pain level is low to moderate, with the patient being not too distressed, but a little off feed and uncomfortable with pawing or even lightly lying down intermittently. Many cases resolve on their own with some light hand walking, which aids in movement of the gas in the bowel. In other cases of gas colic, an injection of a NSAID may be given to further aid with pain and combined with hand walking.
Then, on the opposite spectrum, you have a horse that has a large colon torsion, which is a twist in the large colon. These cases can be very uncomfortable with high heart rates, belly distension, and a horse that will sometimes throw themselves to the ground in pain. A NSAID medication is usually given initially, but in most, there is a need for much stronger medications to keep the patient on their feet and semi-comfortable.
Nasogastric Tube Placement and Colic in the Horse
In some cases of colic, there can be an obstruction within the stomach or in the small intestine just outside of the stomach. This obstruction can then lead to the accumulation of gas, fluid, and feed stuff, which then creates distension and pain for the horse.
In almost all cases of colic, whether if mild or severe, a nasogastric tube is placed which is a long large diameter tube that runs up through the nose, down the back of the throat, and into the stomach. The main purpose of this tube is to check for ‘reflux’, which is an accumulation of gas, fluid, or feed stuff. When the tube enters the stomach, it may automatically create a syphon and allow those fluids to escape through the tube, which then relieves the distension and pain. In other cases, your veterinarian may pump in a certain volume of water in order to initiate a syphon effect. If fluids or gas are retrieved in a concerning volume, then the tube is often left in place to allow for continuous relief. If the ‘reflux’ is negative, many times the veterinarian will then infuse water and mineral oil to help lubricate any blockage that may be present further down the line.
Rehydration of the Dehydrated Equine Colic Patient
Hydration is important to every horse, especially to a horse with colic symptoms. In many cases of colic, the originating cause of that colic pain is a simple obstruction which can be diet or fluid related. This is common in the winter time, with large colon impactions, that are created due to the fact that many horses will not drink cold water. This lack of proper water intake leads to a drier stool or fecal matter, which can accumulate and create constipation or a blockage.
The status of hydration is generally evaluated in all cases of colic, with the capillary refill time and skin turgor test being the most common in a field setting. These two items are evaluated in almost every colic case and depending on the results or concerns, the horse may or may not require rehydration to some extent. In many mild cases of colic, such as a gas colic, the horse is given a bolus of fluids orally via the nasogastric tube, which may assist with low levels of dehydration. In other cases, again dependent on the underlying cause, the horse may require intermittent oral fluids via the nasogastric tube. If the hydration status is really concerning, of if there is a continual loss of fluids as in cases of enteritis or diarrhea, the horses are generally admitted to a hospital setting for continuous IV fluid therapy. These fluids can help correct hydration deficits, replace electrolytes, maintain normal organ function, and assist in removal of toxic byproducts from the blood stream and into the urine.
Management of Infection, Septicemia, and Endotoxemia
These three conditions are not separate in most cases, and are not seen in every case of colic in the horse. In some specific conditions of colic, there may be a compromised section of intestine, which can essentially ‘die’, and thus contribute to massive blood infections in the horse. Infections can also be evident in cases of enteritis and colitis, which often create massive loss of fluids additionally from the body.
Infections are generally detected by elevations in the body temperature, fever, or noted on blood work with increasing numbers of white blood cells or neutrophils. Repeat blood work panels are often done in the more severe case of colic, not just to monitor hydration and organ function, but to detect these infections as they arise. The presence of a blood infection, termed a septicemia, can prove very challenging to manage and create a more threatening situation for the patient. The presence of the infection is one thing, but what it means or implies is another, which is potentially a dead or compromised section of intestine.
Endotoxemia is a release of endotoxin into the blood stream by specific types of bacteria, termed gram negative bacteria. The endotoxin is a protein chain or tail that is located on the bacteria, which is often released as they die off. This protein tail, endotoxin, can create significant reactions in the colic patient, or any patient, contributing to alterations in blood pressure, circulation, hydration status, organ function, and immune response. The presence of endotoxemia can be very concerning and a real challenge for many patients. If the course continues for long and is not managed, death of the horse can be an end result.
Infections, septicemia, and endotoxemia are best managed through IV fluid rehydration, administration of NSAID medications, other pain medications if needed, and specific anti-endotoxic remedies which include plasma or a medication called Polymixin-B. Despite these therapy options, the condition can deteriorate rapidly and create real concern. These patients are often very sick, depressed, not eating, and very dehydrated. The level of care required can be intensive and very costly.
Surgical Intervention in the Horse with Colic
Surgery is often the last thing that any horse owner or veterinarian wishes to happen. For many horse owners, the reason they fear the term ‘colic’ is due to the possibility of requiring surgery, which can carry a high expense and unpredictable future for their horse. Despite this, some cases of colic can only be resolved by surgical intervention, however, not all end up being true surgical patients. Sometimes, surgery is used as an exploratory, to aid in determining the underlying cause. In other cases, surgical intervention is needed, but is brief, and stands a lower level of risk and recovery for the patient. This is common in a case of simple large colon displacement in some scenarios.
Time is of essence in any case of colic. Ideally, we desire that case to resolve in a matter of hours, but this does not always happen. There is a general rule of thumb, ‘never let the sun set twice on a colic‘. This means that really, you have 2 days to manage that case before resorting to surgery. Although this is not a hard fast rule.
Some cases of colic in the horse are really acute and severely painful. They fail to respond to traditional pain medications and other support measures. This generally implies that they have a surgical lesion, which may or may not be able to be diagnosed on the examination. In those cases, there are really only two options. First, you can continue to manage the horse as you are doing, realizing that pain is not controlled and likely, the condition will deteriorate. Or, second, you realize that current therapies are not working and providing relief, thus surgery is warranted to further evaluate your horse. These are situations that no one likes to be in, including your veterinarian. No one likes to see a horse in that degree of pain, and our goal is to eliminate that pain one way or the other. For many of my clients, the decision was made to euthanize, due to ongoing level of care and costs associated. This is a personal decision that needs to be made.
Cases where infection and endoxemia are present create real challenges. First, the presence of that infection or endotoxemia may indicate that there is a section of compromised intestine, which is best removed or resected with surgery. This may be the only way to get a handle or control over the infection. Second, some horses go to surgery and develop secondary infections and endotoxemia after the procedure. In those cases, the diagnosis is a challenge. Is the infection problem a result of the primary condition which was resolved with surgery, or is there a new problem that has developed? It may be hard to say, and in those cases where pain continues, going back to surgery a second time may be the only viable option.
Colic in the Horse; The Good and the Bad News
Colic in the horse is an ongoing problem, but not all horses will experience colic pain in their lifetimes. There is often a difference, on some level, between those that do experience it and those that do not. We will discuss this in another article.
The good news is that the majority of colic episodes in the horse are uneventful and either resolve spontaneously, or with some simple medical intervention. However, the ones that do require surgical or high levels of medical intervention tend to do worse and have a higher rate of euthanasia.
Every horse is different and newer therapy options, supportive measures, and surgical techniques are being created with the passing of years. As these options become available, the success rates with surgical cases are improving.
When we look at colic in the horse and take into consideration the grand picture, including costs to the owner, the ultimate question is what causes colic in the horse? Obviously, there is a twist or blockage created, but is there a deeper problem that is present in some if not all of them? Potentially stemming back to underlying poor gastrointestinal health and function? We will take a look at this in a another article.
Author: Tom Schell, D.V.M., CVCH, CHN