A little about dealing with wounds in animals…

Looking after wounds in animals - equine foal wound

Today’s Diary Entry is sponsored by Chart Stables

Recently I’ve been noticing a lot of pet owners posting online with a picture of an animal with a wound asking for advice. These have varied from a scratch through to a burn, however what all of these have in common is the massive list of comments with different treatments for it .

Now I’ve been fortunate to have attended lectures by wound management specialists such as Georgie Hollis (amazing speaker that if you get the chance you should see!). I’ve also been lucky enough to learn from some top surgeons about the surgical techniques that can complement the management of wounds. Along with my knowledge of the body and physiology and pharmacology I am often left shocked by the advice that I have seen given.

Now a wound is any breakage of skin, this can be from surgery or from trauma, yet the goal is for it to heal so the animal returns to normal functionality and with a satisfactory cosmetic outcome. In fact wound management is becoming pretty much a speciality within veterinary surgery with some amazing results for catastrophic wounds.

One of my textbooks describes wound healing to that of the performance of a symphony orchestra, when each instrument plays it part in conjunction with the other instruments at the appropriate time beautiful music is the result. The same is true of wound healing, when each component performs its function at the correct time uncomplicated wound healing occurs. Going back to the symphony however, if we got a conductor that only understood violin and drums then the music would suffer.

This is the same in wounds, to get the best result we need to know where in the process we are, and then we need to understand what is happening, and what will happen next. To look at wound healing in simple terms there are 4 stages, however these stages do overlap a lot so often it is not possible to define them completely:

During the inflammation stage the body attempts to stop the bleeding from the wound by constriction and clot formation, shuts down the lymphatic system to that area to keep the inflammation local and stop spread of bacteria. There is then microscopic widening of the spaces between tissue cells to allow the spread of cells involved in immunity and repair to reach the place they need to be (hence the swelling of the area). The start of a fibrin clot framework starts, and when exposed to the air this clot forms a scab under which the repair continues.

This is the arrival of cells such as neutrophils and macrophages into the wound which remove any dead tissue and kill bacteria. As the lymphatic system from the wound area is shut down, plasma and other fluids leave the area through the wound helping wash any nasty stuff away. Some of the same cells such as macrophages act as a bridge to the repair stage by sending signals causing the growth of new cells within the wound.

Repair (proliferation)
This is where the forming of granulation tissue occurs with the creation of new blood vessels and skin cells over the wound. This stage occurs around 3 – 6 days after the start of wound healing and creates a barrier against infection. It is also important as the granulation tissue here will contract the wound and bring the edges closer together as well as let other cells use it as a transport system.

Maturation & Remodelling
This is where the wound starts to regain its strength, under the right conditions this can start as early as 24 hours of injury, however the strength is not significant until around day 6 of this process. It continues to gain in strength between days 5 – 15, however the final stage is not reached until around day 21 with no disturbance.

Now this is a really simplified summary (there are textbooks on this!), however just with this it is possible to see how bad management can affect the outcome. Take for example some common antiseptic products; a lot of these are cytotoxic so they kill cells. Now by using these in the repair stage you are simply killing the new repair cells that the body is producing. The use of these in the inflammation and debridement stage however may be beneficial.

Bandaging during the debridement stage can be both good and bad, and a vet takes a lot into account in making a decision here. Bandaging can trap the bacteria next to the wound, however it also gives a way to remove the bacteria and moisture whilst stopping outside contaminants entering the wound. In the granulation stage however a bandage is less important as the granulation tissue provides a barrier against infection.

Something I’ve seen mentioned a lot online is honey. Sadly this is something where a little knowledge is a bad thing. There are certain types of honey that are good for healing (Manuka is one of them), however commercial honey brought in supermarket generally contains bacteria that whilst safe for us to eat in the quantities allowed is not good for wounds. When looking for Manuka honey you need to make sure to get medical grade which is specially produced with sterilisation to ensure that it is 100% pure with no bacteria.

Again another thing I’ve seen mentioned is sudocream, when used correctly it can be great, however using it at the wrong stage can increase the work to debride the wound for example – this is a foreign substance, and is water repellent which while it stops stuff getting in, will also impact bacteria being washed out. It also contains an alcohol, now alcohol used to be used loads for preparing surgery sites… However more recently it does have less use here.

I’ve barely touched the surface, however I hope that I have helped people realise that wound management is not as simple as looking at a picture and asking what cream to use. For those that would like to learn more (plus see some awesome case studies) I would refer you to Georgie Hollis and The Veterinary Wound Library.

Why negative tests at the vet suck…

Babesia blood smear - typical two tear drops

Today’s Diary Entry is sponsored by Spikes World

I am not quite sure how I got to this subject today, however it is something that I thought I would share my thoughts on from the past couple of months. After all as vets we will use tests to work out what is wrong, yet just what are we looking for?

Now diagnostics has played a big part in my life over the past 50 or so days, I’ve seen many physical exams, listened to tons of hearts, and watched countless breathes. I’ve looked at hundreds of radiographs, seen quite a few ultrasounds, and looked at blood and parasite slides.

I believe there are two ways that tests can be used. You can either confirm or eliminate a diagnosis. Personally when I look at a radiograph I am hoping to see something wrong. If we can see something wrong then can attempt to fix it.

So we look at a radiograph, and we see nothing abnormal. Is this really good? Personally I am on the fence here, not seeing anything means that I still don’t know what is wrong. Then there is the other problem, not everything will show up on a radiograph, so sometimes we use special foods or liquids to increase the contrast so we can certain things more clearly. Because we’ve not seen anything on the normal radiograph, does that mean we need to do a contrast radiograph? Or does it mean there really is nothing there?

Same with looking a blood slide under a microscope. If I see something is there it means I know what should be treated… If I see nothing is it because there is nothing? Or just nothing in that drop of blood? Or because it will not show up on the stain I used? Or worse, did I miss the 1 single abnormal cell within the 1000 cells that were on the slide?

Or how about the skin scraping looking for parasites causing the patient to have itchy skin… If I didn’t find anything does it mean that it is not there? Or did I not scrape deep enough? Or scrape in the wrong place?

The worse is the patient where all the diagnostic tests are normal, but the patient’s clinical signs show that they are sick… We can do test after test and they all come back negative…

Sometimes I think diagnostic tests are a dangerous thing, if not used properly they can be a time consuming and very expensive stab in the dark. However what are we supposed to do when they are negative and we are forced into the elimination route of diagnosis?

Is it because the test didn’t work? Or because it really is a negative?

Diagnostics are improving, yet it really is down to the skill of the clinician that uses them that determines just how useful they are….

P.S. For anyone wondering about the picture today, it is babesia, it is the third blood slide that was made for this patient as the first two were negative…