About two weeks ago, we were really concerned about the coyote. His wheezing and coughing became more consistent than it ever had been and we were afraid that our antifungals and antibiotics that he was on just wasn't cutting it. We decided that we needed to do bloodwork and a bronchoalveolar lavage to figure out the EXACT cause for the pneumonia. Blood was carefully drawn by Lou Rae and submitted for analysis at Southern Arizona Veterinary Specialty and Emergency Center (SAVSEC). We needed really specific tests (testing for valley fever and Ehrlichia) along with a complete blood count and biochemistry profile. Once the blood was brought to SAVSEC, it was prepared and sent off to the laboratory (results to follow down below).
To do a bronchoalveolar lavage the coyote needed careful sedation. We had to be very careful not to compromise his respiratory system and choose appropriate sedatives for the task. But, you may ask yourself, what the heck is a bronchoalveolar lavage; or otherwise affectionately called BAL? Let's look a little bit at the anatomy of the the respiratory system of a dog first....
When you first look in the mouth of a dog, or coyote in our case, the first thing you will see is the oral cavity consisting of the teeth, tongue, gums, etc. If you look past the tough however, you will see something called the epiglottis which is a very important piece of cartilage that helps block food, water, and other debris from entering the trachea (otherwise known as the windpipe) unexpectedly. When you "swallow funny" or a friend says "it went down the wrong pipe" sometimes a small amount of food or fluid will enter the trachea bypassing the epiglottis, thus triggering a coughing effect in an attempt to get it out of the trachea! Right above (in anatomical terms "above" is more commonly referred to as dorsal) the epiglottis, if you continue following it back (or in anatomical terms, caudal) you will enter the trachea. This whole thing can be viewed in the image below....
|Canine upper respiratory anatomy|
The trachea is a cartilaginous structure that runs down the neck and then splits (called bifurcates) near the base of the heart. The first "split" or bifurcation are called the primary bronchus and then it branches even further eventually making bronchioles (very, very, very small wind tunnels that do not contain the cartilage as support). If you think of a tree with all of its branches, you can sort of visualize what the trachea (equivalent to a trunk of a tree) turns into. This allows the air that we breath to then enter the lungs...
Now, once the air enters these tiny little branches (bronchioles) it comes to the lung tissue. Microscopically, the lung tissue looks like little balloons and the interface where the air meets the blood stream is called the alveoli (pronounced al-vee-OH-li). If you talk about just "one" alveoli it's called alveolus (pronounced al-vee-OH-lus). The alveoli are basically one cell thick! REALLY THIN! And this helps the oxygen in the air we breath enter the bloodstream supplying the rest of our body with oxygen that is essential to life! Also at this point, since the air has gone through the trachea, then the bronchus (primary, secondary, tertiary) then the bronchioles; the air that is usually dry and sometimes not body temperature is warm and humid - perfect for the red blood cells!
So, now we put it all together and then you have the anatomy that looks like the picture below...
|Canine Respiratory Anatomy all put together|
Now we can revisit this medical procedure called the bronchoalveolar lavage (BAL). I'll preface this with a slight warning... Lou Rae and myself are vaccinated against rabies and therefore qualified to work with wild mammals. You never know what animal may carry rabies so DO NOT TOUCH ANY WILD ANIMALS OR EVEN UNVACCINATED DOGS/CATS; leave that to the professionals. The coyote needed to be sedated because we needed to "lavage" the lower airway with sterile saline. Once sedated (and with an intravenous catheter in place) we placed an endotracheal tube (meaning into the trachea) and gave the coyote some 100% oxygen while we prepped the instruments needed to perform the procedure - STERILE INSTRUMENTS ARE REALLY IMPORTANT HERE. We used a sterile red rubber catheter and carefully inserted it into the endotracheal tube, down the trachea. We then introduced sterile saline into the red rubber catheter to allow it to lavage or wash the tissues in the lung. After a few minutes, we then took a sterile catheter and drew up the fluid we just pushed down into the lungs. This enables us to then submit a sample of the cells and possible infectious agent of what is causing the pneumonia in the coyote. And we got some really good samples! We submitted it to the Arizona Veterinary Diagnostic Laboratory to Carlos Reggiardo, DVM, PhD, DACVM (a veterinary microbiologist). Unfortunately, it did not find a cause for the pneumonia and our sample only consisted of a large amount of inflammatory cells. You can read a little bit more (actually A LOT more) about BAL here.
Our bloodwork returned and showed an extremely high white blood cell count (consistent with some sort of infection). Ehrlichia titers were negative. Our valley fever titers, however, did show that the coyote was exposed (we will talk about immunology during another post) to the fungal organism (Coccidioides immitis)!
So using this information we discontinued the antibiotics and concentrated on the antifungals for treatment along with some anti-inflammatories... And, wouldn't you know it... his most recent radiographs are MUCH improved - take a look!
|Right lateral - October 1, 2011|
Compared to what he looked like initially....
|Right lateral - August 19, 2011|
And there you have it....thankfully the coughing coyote is no longer coughing or wheezing. I hope that we only continue to see improvement in this little guy! His recovery from this horrible fungal pneumonia is only attributable to the volunteers, rehabilitators (Lou Rae, Lisa, and Warren), SAVSEC, and to you...the donor. Which makes our ability to protect Southern Arizona's wildlife everyday possible.