Thursday, April 1, 2021

COPD Explained, Part 2: Diagnostic Tools and Procedures

A very drunk Annie post-endoscope, being 

One of the most important things as an owner (of any animal, really), is having a rough understanding of the diagnostic tools and procedures that our trusted Vets and Techs perform. Some might say, "Well, this is why they went for the training - so they can help us make the best decision possible for our pet." 

Which isn't untrue.

But, I also firmly believe that advocating for our pets is super important and a majority of that is knowing the process. We might not be able to understand it to the levels that our Vets can, but being able to participate in the discussion and advocate for your animal is a responsibility we all should be so passionate about. 

For some background information - I had to really push to get referred to a secondary clinic upon receiving Annie's initial diagnosis. The ideology with some veterinary professionals is that COPD is COPD - wet your hay and reduce dust in your stable, use this drug when things get bad. Done and done.

Out in the open air is best, but not always possible
in some situations and doesn't always resolve
the problem.

Except, my experience and Annie's overall health did not improve with the very mild housekeeping changes and being told, "There isn't really anything else to do... its environmental and you have to manage it better," was very, very frustrating. While I understand that a lot of clinics are limited to what kinds of diagnostics they can run and they are simply doing the best they can with the information they can obtain, I spent a lot of hours changing, modifying and removing things from Annie's life to see if I could make a sustainable change. Much like hundreds of other owners just like me - it didn't work and it made me upset, frustrated, and annoyed at myself for letting my horse down repeatedly. 

It was during this time I found the Faceb00k groups and posted a lengthy SOS message, asking for any and all help. I received an influx of information that quite honestly overwhelmed me at first. There were SO many options I did not know about and so many more diagnostics that could be run that were not talked about during many frustrated e-mail exchanges and phone calls. 

I felt a sense of relief - there were more things that could be done to help my horse and to garner more information about her specific condition. And that alone, made me feel hopeful. 

It made me hopeful that we could get back to this - enjoying
the sunshine and some long trails with my best girl!

I started off by researching the different procedures used to diagnose COPD horses and what information they would provide and started to cross-reference these procedures with clinics in the area to see if they were able to perform them. Long time readers will know I travelled 7+ hrs one way to a clinic that performed a variety of procedures on Annie - and ironically enough, the very first tracheal wash in years. In fact, they had to order tubing and tools because the resident vet hadn't done one in a very, very long time.

So let's dive in - you have a suspected COPD horse or a COPD horse you are trying to manage. What kind of diagnostics can you or do you want to look into? 

(It should go without saying, do NOT attempt any of these procedures yourself. These are meant to be done by a certified veterinary professional and some of them, in a clean and sterile environment).

Respiratory rates and lung sounds will be monitored as part of 
the regular examination.

1. General Exam

The first and foremost of every appointment is a general wellness exam - listening to the horse's respiratory and heart rates, as well as taking their temperature and examining their overall demeanor. This can tell a Veterinarian a lot - such as, if the horse is in respiratory distress and requires emergency medications to assist the lungs in functioning properly. 

A bright-eyed and moderately spirited horse (like Annie), may not show outward symptoms that they are unwell. In fact, one of the comments from the Vet was that she would not have guessed Annie had all that gunk in her lungs based off of how she sounded in her lungs, her respiratory rate and her overall demeanor. 

It looks a bit scary - and can be for some horses - but 
most are pretty reasonable with the entire process.

2. The Rebreathe Test

This can be a moderately confrontational procedure, but it is a basic one that all clinics can perform. Simply put, a bag is placed over the horses nose and "sealed" so the horse is rebreathing exhaled air while the Vet is listening to their lungs for crackling or popping sounds which would indicate damage to the lungs. The rebreathe is a good way of determining this, as it causes the horse to breathe much more intensely. Of course, a horse who is already struggling to breathe is not a necessary candidate for the rebreathe test.

In Annie's first rebreathe, she passed but coughed after the bag was removed. In her second rebreathe, the bag was left on longer and she panicked a bit. She did go into a coughing fit during this, and took a bit to recover from it. It was a bit puzzling for me, considering she marginally passed the first rebreathe but failed the second - so keep this in mind. It does require a level of complacency from your horse (some horses do. not. like. plastic bags over their noses), and a firm handedness from the Vet Tech to hold the bag on steadily.

In both tests, neither Vet who examined Annie heard any lung crackling or popping sounds. Of course, during the exam, horses and Techs and Vets were moving around so it isn't something that is 100% accurate. It can be a good marker for some scenarios, though.

A routine blood draw - there are a variety of different panels 
you can do, but most are similar if you are attempting to assess
the presence of infection.

3. Blood Test

In most cases, Vets will draw blood to search for infection or other diseases that may display on a blood panel. I don't have much to add to this obvious one, as it isn't a very involved procedure but do have one very large cautionary tale: 

This is NOT an accurate indication of infection.

Full stop.

Annie, along with several other horses I have met through the Faceb00k channels had normal blood tests but they did in fact have a large accumulation of mucus and infection in the lungs. 

I had asked the Vet about why Annie's didn't show up and there wasn't really a big answer for me other than, "Sometimes the body compensates." I had asked a few other posters on the groups about their own horses and no one really had an answer either, so it's something to be aware of when you are crossing diagnostics off of your list. 

Would I do a blood test again if I could go back? 

Yes. It had a lot of good information and could have been relevant to her condition (or perhaps another underlying condition which was exacerbating the COPD). 

Food for thought, regardless.

Annie, receiving a tracheal wash at the clinic last year.

4. Tracheal Wash (Transtrachael Wash)

Cornell has a really good article on tracheal wash's here that I've always shared with friends/ those interested in learning more about certain procedures. However, if you don't want to click over and prefer to just read on here, I'll go into some detail about what it's all about!

Tracheal wash's are a procedure where the objective is to collect a lower-tracheal sample (read: NOT into the lungs) to review and diagnose what specimen(s) is present. It can be done in more than just an equine setting and has been used in cows to determine the presence of parasites and other bacteria or viruses, which is pretty cool.

In the case of horses (and also cows, but we're not going to refer to cows anymore other than that point above, haha), the animal is sedated and restrained. The neck will be positioned in a way that allows it to be extended upwards and outwards so that the area where the incision will be is easily accessible and has no potential to be contaminated. 

Once the animal is restrained, sedated and the neck is set, approximately halfway down the neck the Vet will inject a numbing agent and make a small incision to allow the tip of the needle for the tracheal wash to pass through. From there, a large needle with a catheter surrounding it is passed through the incision and through some form of Veterinary magic, the needle is removed and the catheter remains in place in the lower trachea.

Sterile saline will then be injected into the catheter and "washed" down into the trachea. Once it is injected, the Vet will aspirate it back into a syringe to recover most, if not all of the fluid. The fluid that is drawn up will be able to be looked at microscopically. If you have the option to send the slides away for cytologic evaluation, I highly recommend this. Not all Vet clinics are able to perform in-house cytology and it really helps determine what is sitting in the lungs. In Annie's case, the clinic did not have the right dye for the slides and despite them looking at it under a microscope, they couldn't determine all of the findings.

A blurry photo of what was pulled from her 
trachea. Yuck.

The tracheal wash is a good indicator of what degree of inflammatory response is present, and can also determine is in the immediate area. The procedure can also determine what antibiotic is best to treat the infection (if any is present). For example, the bronchoalveolar lavage (BAL) goes further into the lungs whereas the tracheal wash does not. I know I have mentioned in the past "all the gunk in Annie's lungs", but it is only half-true, as the procedure we did only extended down a portion of her trachea. However, it is a good indicator of what is probably brewing further down.

For who don't know or maybe don't remember, Annie's cytology report showed the following: 70% nondegenerate neutrophils (neutrophils are a kind of white blood cell that deals with infections and damaged tissues), 5% lymophocytes (these are responsible for the immune system and low numbers can be indicative of stress, viral infections, or bacterial infections), 25% vaculated macrophages (a phagocytic cell (one that absorbs bacteria and other damaged cells) that tends to group at sites of infection, and a variety of Kirschman spirals (mucus), mild amounts of plant material and rod shaped bacteria which was indicative of a neutrophilic inflammatory response (ie. a higher than normal count of neutrophils in the body, indicating inflammation/ infection) . 

A closer look at the cells collected from a tracheal wash (not Annie's),
revealing mucus (it causes the cells to "line up" and "stick together), as well as
non degenerate neutrophils (arrow) and hundreds of eosinophils. 

As a quite sidenote, if you want more information, South Mountain has a great list of all the different cells in the horses body (along with vitamins and minerals) with a detailed explanation in regards to blood tests. The whole learning curve on cells and what they do is still a mystery to me in some ways, but it's important to research your horse's medical findings to fully understand what it all means. I have been unable to find any concrete research regarding the "normal" levels of cells in a healthy horse, as I imagine it's something that is still being researched and understood.

Injecting sterile saline down the tube as part of a routine
BAL procedure.

5. Bronchoalveolar Lavage (BAL)

As said previously, the bronchoalveolar lavage (BAL) allows the Veterinarian a deeper look into the lungs and to determine what level of inflammation is present. There is arguments that the BAL is "better" than a regular tracheal wash, as it is pulling information from directly down into the lungs itself. However, it may not be available in your clinic (it wasn't for me), so a tracheal wash may be the only way to go.

This sample is indicative of EHV-5. The large cell is a mutlinucleated macrophage, which
contains prominent large nucleoli, indicating an activated state

The BAL is a lot less invasive of a procedure (and can be done out of clinic), but does require some additional gear. Once your horse is sedated, your horse's neck and head will be lifted and stretched to make entry into the trachea much easier. The Veterinarian will insert a tube down into the horse's trachea and into the lower airway. From there, sterile saline (and quite a lot of it) is flushed into the area and pulled back where the liquid will be made into slides and sent away for analysis. One thing to know is that even if some fluid is retained in the lungs, it generally does not cause any issues as the large veins within the lungs rapidly absorb the fluid.  

An endoscopic exam being performed.

6. Endoscope

While it can be confused with a gastroscope (a scope that looks into the stomach; ie: for ulcers), this tool is used to view the contents of the trachea. It is commonly used in COPD cases to determine what is in the trachea, and with some endoscopes, small samples can be taken from identified problem areas. Horses can be sedated or not, as it is widely dependent on if the horse's larynx also needs to be actively viewed (ie. assessing the normal function of the larynx).

In Annie's case, she was sedated and reacted heavily to the endoscope being moved within her trachea. There was a lot of coughing and the poor vet ended up getting a nice coat of mucus on her face and in her hair (we were the very first appointment of the day to boot, oops). The findings were consistent with the tracheal wash - irritation was present in the airways, as well as some mucus along the sides of the trachea. However, it was also noted that the endoscope was performed after the tracheal wash, so findings weren't as severe as they potentially could have been. 

A repeat photo because I can't find a stock
image of a thoracic ultrasound being performed.

7. Ultrasound

While it isn't always a common procedure in the world of diagnosing COPD, it can be very beneficial in determining the overall health of the lungs and what the structures look like from an imaging level. It's important to remember that an ultrasound will only show you the surface of the lungs itself, so while it is not entirely a three dimensional view, it can provide a lot of information about how the lungs are working and if there is any damage present. 

Essentially, your horse will have a large amount of isopropyl alcohol squirted over their barrel and the vet will run their imaging probe over the area as the horse inhales and exhales normally. The Vet can identify any damage, fluid, tumors, or abscesses (etc) easily with this process. In Annie's ultrasound, the damage was easily seen as rippled "waves" instead of a smooth line and was categorized as moderate.

An xray of the fetlock joint, because I couldn't find a photo of 
chest xrays being taken.

8. Radiographs

If needed, a Vet may want to obtain some radiographs of the thoracic region (ie. chest) to further investigate for any potentially missed obstruction or otherwise if your horse is not actively responding to COPD treatments. If an ultrasound is not possible at your Veterinary location, radiographs may be a good option for investigating what the lungs actually look like.

For reference, Annie did not receive any radiographs of her lung/chest region. 

It is typical to do a blood test to determine allergens.

9. Allergy Testing

One of the most underrated and widely misunderstood tools out there is the allergy panel. Based off of what I've seen online and in practice, some Vets swerve away from the idea of allergen testing for reasons I am not privy to, but some seem to recommend it above several other diagnostics. While I have not had the opportunity to have Annie allergy tested since her diagnosis, we are scheduled for an allergen test in May which will hopefully bring about more answers about her condition and her sensitivities. 

So what is an allergy test?

In most cases, it is an blood test performed by a licensed veterinarian that is then sent off to a lab for processing. It can also be a skin test where a small amount of suspected allergens are injected beneath the skin and monitored for a reaction.

An alternative way to test for allergies.

Depending on what lab you use, your horse will be tested for the items/ factors they have on file. I researched several labs extensively, and found that Nextmune (formally Spectrum Labs) is the only equine-approved lab that also tests food sensitivities (ie. rice bran, beet pulp, apples, etc). 

Most labs I found (Heska, Idexx) test for the following: Grasses, Weeds, Trees, and sometimes Fungus/ Molds. 

However, please do your research when deciding what lab to go with. For example, Nextmune tests for: Grasses, Weeds, Trees, Fungi, Foods, Indoor items (ie. shavings (variety of types), wool, etc), Insects and Grains whereas Heska only tests for Grasses, Weeds and Trees. It can be pretty disheartening to spend the money on a test and not get the information you need, so please do the research or ask your Vet what each lab cover, or if there is a possibility of adding additional allergens to the panel itself.

From there, the results will give you a guideline as to what your horses tolerance levels are and if the exposures can be managed externally (ie. a horse allergic to alfalfa being removed from alfalfa hay and only receiving grass hay) there is no further action required. However, if the allergen cannot be completely removed (ie. trees, weeds, etc), immunotherapy is the next step.

Once the test results are received, a special and personalized immunotherapy
shot is developed based off of the specific sensitivities your individual horse has.

Immunotherapy is the process in which the allergens are introduced slowly to allow the body time to build a tolerance level for it (them). It is a series of shots in very small doses (3-5ml) that are injected (there is also an oral series for needle-phobic horses and owners) just under the skin. These injections are given on a set schedule, especially during the beginning of the process as the body is working to become desensitized. From there, injections may be given every month or few months depending on the horse and their requirements. 

As more research and more diagnostic tools are developed and the world of COPD is better understood, I am sure this list will become larger and much more refined. For now, there are several options for owners who are looking to diagnose and improve the lives of their horses. It can be a very frustrating condition, but knowing what options you have and arming yourself with the knowledge is half the battle - in my own case, pushing for "off the beaten path" diagnostics saved my horse additional scarring and trauma to her lungs and the side effects of being on medications long-term. 

If anything - take the time to find out what services your immediate clinic offers and see what procedures would best benefit your scenario. As always, talk with your Vet and develop a game-plan as to what the best options are and being mindful with any financial restrictions you may have in place.

The next installment I am excited for - I'm going to go over medications, what they do and what they are for, the use of the nebulizer (Flexineb) and if it isn't too long and boring, possibly some supplements/ homeopathic options.


  1. What a journey you’ve been on. Thank you for sharing it.

    1. I'm glad to share if it means it helps someone in the same position as me <3

  2. Thanks for all this great information. I really need to allergen test my horse this year and your breakdown on what the different labs do is helpful.