Browsing tag: dehydration

Colic: Part 2: Medical Colics

In my last piece, I looked at how the vet will examine a horse with colic. Following this, and using all the information from the history and workup, he or she has to decide if the colic is Medical or Surgical. The terms are more or less self-explanatory: a medical colic can be managed with drugs, while a surgical colic needs emergency surgery.

As a rule of thumb, 9/10 colics are medical, and can almost always be managed on the yard.

So, here are the common causes of colic that we see in the UK1 :

1) Spasmodic Colic. This is probably the commonest, and perhaps the least understood; I estimate about 80% of Medical colics are Spasmodic. Spasmodic colic can be caused by a stressful event, mild dehydration, or be genuinely idiopathic (i.e. we don’t know what causes it!). It can also be caused by severe tapeworm burdens. In a Spasmodic Colic, a section of the gut goes into a spasm, preventing anything from moving past it. It can be acutely painful, but usually responds really well to management with drugs. For any horse that has two or more bouts of spasmodic colic, I’d always recommend a tapeworm blood test to make sure it isn’t part of the problem!

2) Impaction Colic. This is more common in some management systems – it is pretty rare, for example, in horses who live on grass. In these cases, the food in the large intestine dries out a bit too much, and turns into a putty-like material. It then gets stuck, typically at one of the 180- degree turns in the Large Colon. It’s also strongly associated with moderate dehydration – as a horse gets dehydrated, he will move water out of the gut in order to keep up his circulating blood volume. This is a clever trick, meaning a horse can survive levels of dehydration that would kill a human. However, if the water isn’t replaced, and he’s been eating dry hay, his gut contents can become so dry they cause an impaction. This is why, many years ago, bran mash and Epsom salts were fed after hard work – both are good ways of rehydrating the colon and Caecum contents.

3) Gut displacements and entraptions. These are a bit of a mixture – some are medical, some are surgical, some look surgical but aren’t, and some can be fixed medically but keep coming back so surgery is eventually needed. What many people don’t realise is that the guts are in constant motion. Occasionally, a loop of intestine goes “wandering around” inside the abdomen, and gets stuck behind something else (for example, into a little gap between the spleen and the kidney). These can often only be diagnosed by rectal exam, and can feel really confusing, where nothing seems to be exactly where it should be! Each case has to be treated on its merits, and many can be resolved by lunging – presumably because jiggling everything around helps the intestines to fall back into their proper places! Personally, however, my inclination is generally to refer the horse as a possible surgical case, because it’s amazing how often a trip in the box fixes a displacement or entraption. Of course, if they can’t be rapidly resolved, they need to have surgery to put everything back, before any permanent damage is done.

4) Sand colic – I’ve only rarely seen these; they’re normally caused by the horse drinking from sandy water. Over time, sand builds up in the intestines, causing irritation and sometimes an impaction. Management usually revolves around maintaining gut motion with laxatives and pain relief; however, surgery is sometimes needed to evacuate the sand and debris from the gut.

5) Inflammatory diseases, e.g. peritonitis or anterior enteritis. I’m including these here because they’re not strictly surgical. However, they can be really hard to differentiate from surgical cases, and they’re usually only diagnosed after referral, with the advanced techniques available at a referral hospital.

6) Other medical causes, e.g. diarrhoea, or stomach ulcers, can also cause a “Medical” colic; however, these cases require the underlying disease to be treated, at which point the colic symptoms will resolve themselves.

Treatment for medical colics is focused around pain relief and maintaining hydration. Spasmodic colics especially respond very well to a mixture of hyoscine and a pain-killer, which relaxes the spasming gut segment, allowing normal gut movement to be re-established.

Using a painkiller (e.g. injectable bute) can also be a really useful diagnostic test for whether a horse needs surgery – one of the standard guidelines is that a horse with a heart rate over 60 beats per minutes, 30 minutes after intravenous bute, is usually a surgical case. The other painkiller (flunixin meglumine) is almost never used, unless surgery is definitely not an option. This is because it is too powerful! Even horses with dead bowel can look bright, healthy and well, until the flunixin wears off. At that point, they crash, and are often too far gone to be saved.

Equipment for the medical treatment of colic

Equipment for the medical treatment of colic

For impactions, rehydrating the gut contents is vital, but pain relief is also really important. In these cases, Epsom salts and water by stomach tube are really useful. There is some controversy over the use of liquid paraffin in impaction colics. If the horse later has to go to surgery, the presence of liquid paraffin in the gut can cause major headaches for the surgeons; on the other hand, it can be a marvellous lubricant to help move things along. Personally, I tend to give any impaction colic a bucket by stomach tube containing a mixture of water, electrolytes and Epsom salts; and if I’m sure it’s not surgical, I’ll add in a litre or two of liquid paraffin as well. Liquid paraffin is horrible stuff to work with, and if all you’ve got to give it with is cold water, it’s not easy to mix in; I like to mix the water and electrolyte tablets or sachets together first in a bucket, then add the paraffin.

The tube is passed down the nose and (hopefully first time!) into the gullet (if it goes into the wind pipe, start again…), and down all the way into the stomach. To check it’s in the right place, I always feel for it passing down the throat, listen for air moving as the horse breathes, and then suck on it to see if I get lots of air back (means I’m in the airways) or nothing (means I’m in the gullet) or, worst of all, a mouthful of stomach contents. This means the tube is in the stomach, which is great, but it tastes truly vile! Once I’ve carried out all those tests, I’ll pour in a tiny amount of clean water, just to be sure – if the horse coughs, it means the tube is in the windpipe despite all my tests, but it’s not the disaster it would be if I’d poured in a couple of gallons of liquid…

To get this lot into a horse, some people use stirrup pumps – they’re a bit like bicycle pumps, and attach to the end of the stomach tube. This is used to pump fluid from the bucket down the tube – they’re great if you’ve got them, although you have to be careful not to overfill the stomach. However, most of us still use syphons and funnels. The tallest person present (usually me…) attaches a funnel to the top of the tube, then fills the funnel from the bucket. They then hold the funnel as high as they can, so the liquid runs down the tube into the horse’s stomach. You then repeat this until either the bucket is empty or the funnel stops running, which normally means the stomach is full. It’s messy, and can be physically pretty hard work, but it’s a vital part of treating an impaction colic. Personally, I quite often use it to rehydrate the gut of any severe medical colic, because anything that causes gut stasis can lead to a secondary impaction if you’re not careful.

I’d normally treat a definitely diagnosed impaction with injectable bute for pain relief. There is some evidence to suggest that the use of anti-spasm drugs like Buscopan can help to encourage normal gut action, even though they are designed to work as gut relaxants, but I think that particular debate is still open.

To maintain hydration, some vets also like to start a drip line for intravenous fluids. This won’t help the gut (any excess fluid will be excreted by the kidneys before it gets there), but it can help to support the circulation of the horse. Personally, my thinking is that most colics that are so severely dehydrated that they need a drip are either surgical or have another, underlying disease; however, there are always exceptions!

Chronic, ongoing colics can be a nightmare to manage – they’re typically low grade, spasmodic colics, or mild impactions. In these cases, a more thorough examination (including blood tests) is indicated, to try and rule out any underlying disease. Chronic impaction problems tend to be management related, and can usually be resolved with minor tweaks to management. However, your vet will often want to check your horse’s teeth – this is because dental problems can result in poorly chewed food, which can make impactions more likely.

My experience with the chronic spasmodic colics is that if there’s no other underlying cause found, they can occasionally respond nicely to a course of probiotics. I had an incredibly frustrating case once of a horse that had repeated bouts of colic, that we never got to the bottom of. I was being called out every few weeks (and the yard was nearly thirty miles from the practice, which made each visit something of a nightmare!). Eventually I suggested we try a month’s course of probiotics… and the next time I saw the horse was nine months later for annual vaccination. Any further colic episodes, I asked? No, they replied – nothing since we started the probiotics. Although it isn’t a cure-all, it can apparently help in some cases!

Of course, not all colics are medical – about 10% require surgical management. In the third and final piece of this series, I will look at the indications for surgery, the types of colic needing surgery, and then I’ll go through what happens when your horse is referred to an equine hospital for emergency surgery.

1 This is based on my clinical experience in the Midlands, Wales and the South West of England. In some parts of the country, other causes will be more common – for example, on the South Coast, Sand Colic is more common. However, it seems to be fairly rare in most areas, so I’m not going to cover it in great detail.

If you are worried your horse or pony may be suffering from colic, talk to your vet, or check the symptoms using our Interactive Equine Symptom Guide to help assess how urgent the problem may be.

Colic: Part 1: Diagnosis and Workup

Horse colic examination and anatomy
When talking about colic, it’s important to have some idea of what the various parts of the equine gut are… So, here we go:
Stomach – quite small, and hidden away deep up in the ribcage.
Small intestine - this is very long, but quite narrow (perhaps 1 or 2 inches across). It is all coiled up throughout the abdomen.
Large intestine – this is divided into three parts:
The Caecum is a large sac perhaps four or five feet long, pointing forward, and can be heard on the right flank. Generally, it makes a loud gurgling noise every 20 to 30 seconds in a normal, healthy horse.
The Large Colon makes up a double U shape, lying on the bottom of the abdomen. It can be up to a foot across, but at each end is a sharp 180-degree bend; the bend near the pelvis (the pelvic flexure) is especially narrow.
The Small Colon runs from the large colon down to the rectum, along the top of the abdominal space.

It’s something all horse owners dread – colic. However, colic is a symptom, not a disease in its own right, and has a wide range of different causes. This is the first in a three-part series where I’ll be looking at colic in horses – its diagnosis and treatment, and what happens if your horse has to be referred for surgery.

Put simply, all colic is, is abdominal pain. However, before you’re tempted to dismiss it as a stomach ache, it’s worth remembering that the horse’s intestines are as complicated as a major chemical factory! Anything that causes disruption to their function is potentially life-threatening.

Occasionally, colic pain comes from a non-intestinal source, e.g. Liver disease (think ragwort poisoning, or liver fluke), or a kidney issue. In mares, it can also be caused by certain disorders of the reproductive tract. However, the vast majority are due to disease, damage or malfunction of the intestines.

If you call your vet and tell them that your horse has colic, they’ll treat it as an emergency, because it can be. They’ll generally take a bit of history from you, a quick description of what the horse is doing at the moment, and then they’ll head out to examine the horse. Most vets will also give instructions for what to do while you’re waiting; it’s important to do what they say, not what someone else on the yard suggests. This is because they may have an idea what sort of colic your horse has, and will try to tailor their instructions to the specific case. For example, some forms of colic respond well to being trotted around on the lunge; however, that can worsen other types.

When they arrive, the vet will want to establish three things:
Firstly, does the horse actually have colic? I’ve been called out to “colic” cases that proved to be laminitis; to a mare foaling down; once even to a tired (but perfectly healthy) horse sleeping in his stable!
Secondly, assuming it is a colic, is it a Medical or a Surgical Colic? (I’ll talk more about this distinction in a minute).
Third and finally, can they make a specific diagnosis of what kind of colic it is?

Every vet will have their own routine, but my workup goes something like this:

What’s the horse’s behaviour like? Is he alert, or dull and unresponsive? Is he thrashing about, or just looking at his flanks occasionally? Generally, a quieter horse is likely to have a milder colic, unless he or she is so toxic that they are depressed or spaced out. One exception is that some spasmodic colics are incredibly painful – however, the pain usually comes in waves.

Are there any droppings in the stable? Hard, dry lumps of faeces is suggestive of an impaction, or blockage; while very runny faeces or diarrhoea may suggest colic secondary to an infection, e.g. Salmonella.

Then I’ll start my examination:

Mucous membranes (gums are usually most accessible and reliable) – what colour are they, what is the refill time, are they tacky?
The normal colour is described as being “salmon pink”, and if you press with a finger for a moment, the colour should fade to white, then return within 2 seconds. They should also be nice and moist to the touch. If they are red, or purple, or the colour doesn’t fade, it is highly suggestive of toxic shock (like septicaemia). This is a marker of a really, really severe injury to the gut wall, that’s allowing bacterial toxins to enter the circulation. If the refill time is greater than 2 seconds, or the membranes are tacky or dry, it suggests dehydration and/or shock.

Heart rate - how fast, is the rhythm good? As a (very rough and ready!) general rule, a heart rate under 60 beats per minute implies a Medical colic, while over 80 suggests a Surgical case. If there’s an abnormality in the rhythm, it can mean heart disease as well, or severe toxic shock.

Gut sounds - what do the guts sound like in all 4 quadrants?
This is where you’ll see your vet putting a stethoscope to the horse’s flanks, listening to the guts. The normal, healthy gut makes a wide range of bubbling, gurgling noises (the sort that anywhere else you would associate with really cheap plumbing!). The bottom left is the left Large Colon, bottom right is the right Large Colon and perhaps some Caecum, the top right is the base of the Caecum, and the top left is mainly small intestine. This is one of the most useful tests we can do – reduced sounds mean the guts are “slowing down” – this can mean an impaction or blockage, but it can also mean a serious disease e.g. a twisted gut. Increased sounds is generally a good sign, as it usually means a Spasmodic colic.

Finally, I’d want to take the temperature (a horse with a fever is likely to have another disease, e.g. Salmonella, that is the underlying cause of the colic), and then, if at all possible, do a rectal exam. People get very excited about this, and it’s one of the standard jokes about vets, but I’d like to go on record and say that I doubt anyone actually enjoys rectalling a horse! Apart from anything else, it’s dangerous to the vet, and uncomfortable to the horse… However, it can provide more information than almost any other test. What we’re feeling for is anything unusual: is the large colon a normal size and texture? How about the Caecum? Can you feel the small intestine? Usually, the small intestine is almost impossible to feel – it just slithers out of the way. If, however, you can feel thick, swollen loops of intestines (they feel a bit like black pudding, or really thick, soft sausages, if you’re interested!), it is an indication of a complete blockage in the small intestine, which needs emergency colic surgery. On the other hand, if you feel a doughy, squishy mass in the colon, that means the horse has an impaction.

Sometimes, if there is doubt about whether food is passing from the stomach or not, the vet will pass a stomach tube and see how full the stomach is. This looks really easy in theory – you pass a tube up the horse’s nose, he swallows it, and then you syphon out the stomach. If you get lots, it’s too full, if not, it’s fine. However, not all horses are quite so easy! Some horses are really difficult to get to swallow the tube, and it can take several attempts to make sure it’s not in the windpipe (which would be a disaster). Also, the equine stomach is, as one equine surgeon I know once put it, “a fantastic organ – it can be completely dilated (full), and you’ll get nothing out of it until you move the tube half an inch, then it all comes spurting out”. However, if there’s any doubt, it can be a great tool to ensure that there isn’t a rapidly life- threatening blockage; it can also be emergency first aid to prevent the horse’s stomach rupturing in a severe surgical colic.

The vet will also sometimes take blood samples – we tend to hold onto these in case they’re needed, but the main things we’re looking for are:
1) Evidence of dehydration – the blood tests will allow us to quantify the degree of dehydration, making it easier to plan a course of treatment.
2) Evidence of infection – if the white cell count is significantly abnormal, it suggests there may be something else causing the colic that we might need to look into.
3) Liver and kidney function – sometimes liver or kidney disease can present as colic
4) MOST IMPORTANTLY – Fibrinogen levels. Fibrinogen is a substance that can be used to assess inflammation and tissue damage – a high Fib level in a colic case is very suggestive that the gut integrity is damaged, and that surgical intervention may be needed.

There’s one other sample that can be very useful, especially as a “rule out” test if the clinical findings are contradictory or unclear. This is a peritoneal tap. This test carries some risk, but sometimes it’s the best way to find out what’s going on inside the abdomen. The belly of the horse is clipped, and prepared so make it as sterile as possible – we don’t want to risk introducing infection. The area is numbed with local anaesthetic, and then either a small incision is made with a scalpel and a blunt cannula inserted or (more usually) a small sterile needle is VERY CAREFULY inserted through the abdominal wall. The fluid that comes out is collected in a sterile sample pot for examination. The risk, of course, is that damage is done to the intestines; however, we’re very careful to avoid them as far as possible, and instead to collect the fluid that surrounds the intestines, the peritoneal fluid. In the lab, the numbers of cells can be counted to assess if there’s infection in the belly (peritonitis); however, in the field we can tell three things:
1) The tap fluid is clear (you can read text through it) yellowish – this suggests that the abdomen is basically OK, and means that in the absence of any other findings, the case can be managed medically.
2) The tap is cloudy, reddish or umber in colour - this means severe damage to the gut walls and/or peritonitis (infection in the abdominal cavity). This horse needs urgent referral for investigation at a hospital.
3) The tap contains gut contents (green or brown, lumpy) – sadly, this means that the intestines have ruptured; the horse is highly unlikely to survive. Alternatively, this may mean that the needle has gone into a part of the intestines, so if I get this, I’ll usually repeat the tap a few inches away, to make sure. If the needle has damaged the intestine, it’s not a disaster, but it is something to be avoided if possible.

So, using all the information from our history and workup, the vet has to decide if the colic is Medical or Surgical.

The terms are more or less self-explanatory: a medical colic can be managed with drugs, while a surgical colic needs emergency surgery.

As a rule of thumb, 9/10 colics are medical, and can almost always be managed on the yard. In my next blog, I’ll be looking at these Medical colics, their causes and treatment.

If you are worried your horse or pony may be suffering from colic, talk to your vet, or check the symptoms using our Interactive Equine Symptom Guide to help assess how urgent the problem may be.

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