A Honking Wookie

Tracheal Collapse in a Pomeranian

By Jill M. Patt, DVM

Introduction: We should begin by defining a Wookie.  A Wookie (with one “e”) in the sense of this article is one of my 3 Pomeranian dogs named, of course, Wookie (actually Mr. Fuzz is Wookie of Sierra). Wookie is a neutered male who will be 4 years old in January 2016. He was show-bred and of lovely type, but early on, he had to have his hip removed, and he was subsequently neutered and thus never shown. He was lovingly raised from infancy, always provided the best diet, had no traumatic injuries, and has always been walked on a harness (never a collar).

Unfortunately, Wookie is also your quintessential or stereotypical Pomeranian who loves the sound of his own voice and thinks the ankles of any stranger taste great. Fortunately for him, he just looks at his family with those beautiful Pomeranian eyes, and we melt, so yes, he too often rules the show. However, due to his very reactive tendencies, we began working with Jubie & Kama Rueschenberg of Club-Doggie (12) as they were one of the few positive reinforcement trainers willing to take on this then 4-pound fur ball of storming energy that would gleefully attack a Great Dane or a Mailman.  With their assistance and much training at home, we were able to teach our Wookie and our other Pomeranians much more than we ever had attempted to teach a dog before. This led to some animal acting for his sister and their Facebook page, “My Pom Pals” (9), which serves as my outlet for their numerous photos and videos. 

Because I post just about everything regarding the “kids” on their page, I also decided to post information and videos of Wookie’s struggles with his breathing and his eventual outcome. These posts have led to the request for a more formal article about our experiences together.  So, this is Wookie’s and my story on how we managed his collapsing trachea, how decisions were made in his care, and treatments selected. It delves into the various options and the personal difficulty of making these decisions for him in spite of the fact that I’m not only his mom but a veterinarian. My hope is that it will relay useful information to other owners going through this with their dogs and also share the importance of conducting more research into this devastating disease, which has no cure.

As a puppy, our boy had an occasional cough that could be induced with just a gentle rub on the trachea, but this was avoided with the use of a harness, which did not limit him in any way. However, as he aged, he began to exhibit the typical goose honk sound whenever he was very excited and breathing deeply.  Over time, the goose honk progressed to occurring during periods of non-excitement and then to actual breathing difficulties even while resting. From an owner’s perspective, it felt like this escalated quickly, but in reality, the honking had been slowly worsening over this past year (currently 3years old). 

Tracheal Collapse:

We should start by defining what the trachea is. The trachea is the central airway of the dog that delivers air from the pharynx into the primary bronchi and then into the lungs. Think of the upper airway as an upside-down Y with the single part of the Y traveling down the neck (cervical region) and into the chest (thoracic) region. The trachea then splits into two branches called the main stem bronchi, which then branch further into ever-decreasing airways that deliver air to the lungs. So the lower part of the airway system can be thought of as the branches of a tree through which the oxygen molecules travel. A breath is taken, and the oxygen travels down the trunk (cervical & intrathoracic trachea) and into the main stem bronchi (first split in the tree trunk) and then down into the smaller branches that go into lung lobes above the base of the heart. The oxygen molecules continue their journey by traveling down the ever-decreasing branches of the respiratory system and finally into the smallest areas where they can be absorbed into the blood system and are picked up by red blood cells and carried throughout the body for its use.  For a more medical description of the trachea, I encourage you to view WikiVet(1), which provides a nice online reference. Also see Veterinary Partner(2) for further review.

Moving on, we need to define what occurs when a trachea collapses. And why was Wookie honking? The dog’s trachea (tree trunk) is made up of a series of cartilage-based C-shaped rings surrounded by muscle tissue, with the open part of the C covered by a membrane on the top, which allows for some stretching and expansion while breathing. I often think of the look of a dog’s trachea as similar to the tubing used by an asthmatic human to breathe in from a nebulizer cup, with the top 1/4 of the tube cut off and covered by this membrane. The honking sound is a result of the tracheal collapse. As the cartilage in the tracheal rings starts to break down or weaken, the fixed C shape starts to flatten out, which causes a widening of the tracheal rings, resulting in stretching of the upper membrane and eventual sagging into the interior (lumen) of the airway. When the pet takes a deep breath, this sagging is exacerbated and airflow is disrupted, resulting in a honking sound. Think of breathing evenly through a soft or flexible straw and then suddenly taking a deep breath. The straw would flatten, and a sound would be produced similar to what occurs during a collapsing tracheal episode.

Medical Management:

Once diagnosed, the first efforts made should be in reducing and eliminating exacerbating factors, and in dogs, this is typically obesity, which is well known to worsen the degree of collapse. Medical treatment is generally approached from 3 directions: 1) eliminate contributing factors such as obesity or secondary infection, 2) reduce the cough, which leads to more inflammation, and 3) reduce the inflammation already in the airway.

In Wookie’s case, obesity was not a factor, but he was placed on an even more strict diet, and then we addressed the inflammation. Our first efforts at decreasing inflammation were with just the use of an antihistamine to decrease respiratory secretions and the “stickiness” of the membrane. In Wookie’s case, this made no difference. He was also placed on steroids to reduce internal swelling. Steroids are medications such as prednisone/prednisolone that are very potent anti-inflammatories but not without side effects, including elevated liver enzymes, diabetes, secondary infection, weight gain, and more. Therefore, this was not our first choice, but it became necessary in his treatment and provided him with some relief. We also had to reduce the cough and or honk, and this wasn't easy with Wookie due to his excited tendencies, described above, which exacerbated his breathing efforts. We opted to place Wookie on Hydrocodone Bitartrate (also called hycodan or tussigon)(3), which is a controlled drug that is very good at controlling the cough but also slightly sedates the dog. Lastly, we opted to place Wookie on a broad-spectrum antibiotic to rule out inapparent infections. As a side note, the best way to determine if an infection is present in the lower airway (lungs) is to anesthetize the pet and flush fluid into the airway and suction it back out for bacterial culture. We initially didn’t want to subject Wookie to this, so we placed him on the trial of antibiotics, but this was eventually done during his bronchoscopy.

During this time, Wookie was examined, and his medical therapy was directed by his internist from Desert Veterinary Medical Specialists, Dr. Melissa Riensche, a diplomate of the American College of Veterinary Internal Medicine(4). His nervous mom needs to give many thanks to Dr. Riensche for all her time, attention, and dedication to his care.

It should be stressed that medical therapy and controlling secondary factors are the primary means of treating tracheal collapse and that surgical intervention is reserved for those cases that prove non-responsive to all other efforts. Unfortunately, Wookie was one of these cases. Despite aggressive medical therapy, his condition worsened, and he entered into a state of crisis that required injectable sedation and emergency hospitalization in an oxygen cage. At the time of this crisis, he had further diagnostics completed at VCA Animal Referral and Emergency Center of Arizona(5) with Dr. Dennis Keith (Medical Director, DACVR) and Dr. Christopher Monarski (Veterinary Specialist, DACVS-SA), which included fluoroscopy (moving video x-ray) and a CT scan. Both diagnostics indicated the severity of his trachea collapse, with the narrowest part of his airway only 2mm wide during an episode. We seriously considered intervention (tracheal stenting) at that time. Still, during the course of completing the diagnostics, his breathing stabilized, and we opted to take him home and continue medical therapy.

Wookie’s very nervous veterinarian/mom did extensive research, including reading and consulting with a variety of experts in the field during this time. Unfortunately, even as a veterinarian, the decision on when to intervene and which option to choose proved to be very overwhelming because there aren’t any outstanding options for this condition.

Wookie’s Treatment:

After much research, our choices for Wookie were as clear as mud. So, what we decided to do is admit Wookie for bronchoscopy(10), which involves general anesthesia and running a bronchoscope down into his airway to view the inside of the trachea and the opening to the bronchi. During this procedure, a culture of the airway can also be done to look for hidden bacterial infections. Our decision was to consult with both a surgeon experienced at extraluminal ring placement(7), and if, during the bronchoscopy, only cervical tracheal collapse was noted, this option would be chosen. Alternatively, if more collapse was pointed out in the thorax, Dr. Riensche would complete stenting. Unfortunately or fortunately, depending on the perspective, Wookie had extensive collapse along his entire airway, so we elected to have Dr. Riensche place an intraluminal stent.

Placement of the intraluminal stent was determined to be needed, but what type of stent and what size should we use for Wookie? While stent placement is a fairly straightforward procedure, it should be done by a facility that has access to fluoroscopy(11), allowing for exact positioning of the stent within the trachea, and by a specialist who is experienced at selecting the appropriate-sized stent. Also, the actual type of stent used is important, as older stents were made of a material that often fractured over time(8) and were not tapered to the conformation of the trachea. Wookie’s previous CT scan helped us know the diameter of his airway, but remember that he had significant swelling present, so these measurements were not necessarily specific to the actual size of his trachea. Generally, stents are placed that are approximately 10-20%(8) larger than the existing trachea size. In the past, stents were only placed in areas with visible tracheal collapse; however, most veterinarians currently stent the entire airway if deemed necessary. Thus, the end result of our decisions with Wookie was to have Dr. Reinsche stent the majority of his trachea with an Infinity brand stent(8) using fluoroscopy-guided placement. 

Wookie’s breathing was at its worst the day of the procedure, and he had his consult in the morning with both the possible surgeon, Dr. Enwiller(7), and internist Dr. Reinsche(4). He and I then waited until they were both ready to do his procedure, as prior to the scoping, we didn’t know if he’d be a candidate for the surgeon’s placement of the extraluminal rings, so it was important to have both specialists available at the same time. While waiting in the lobby listening to his struggle to breathe, it was clear that after all the research and doubt about whether and when we should intervene, the time was clearly at hand, and he needed our help.

The bronchoscopy was completed, and the stent was placed while he was under general anesthesia. Immediately upon awakening, his breathing was quiet. It was an incredible relief not to hear him struggle to breathe. He did amazingly well following the procedure and was sent home that same day.

We initially kept Wookie very sedated, and he was on a total of 11 different medications (medical therapy doesn’t suddenly stop). Still, we eventually weaned him down to a lower dose of prednisone, hydrocodan to suppress the cough, and a sedative only as needed for over excitement. We hope to get him off the prednisone entirely and to a point where the cough medication is used only as needed. The cough suppressant is necessary following stent placement because the patients will have airway irritation due to the foreign device present in the trachea, and this can cause a cough that could potentially move or dislodge the stent. Once the stent is more secure with the regrowth of the normal tracheal cells, the cough medicine is tapered down to only as-needed dosing.

Conclusion:

So what does the future hold for Wookie and other patients with tracheal stents? The most honest answer is that we don’t really know. The cause of trachea collapse is still largely unknown, although genetics is assumed to be involved. The newer stents have not been around a long time, and every patient responds differently to a prosthesis in their trachea.  What we do know is that Wookie was at a point where we had no choice but to intervene, and that by having done so, he is now able to breathe easily with no honking and has even begun to play a little. Our hope for him and others is that he has a long life, but most importantly, a life of good quality, and we hope that is what we have provided him.  Thank you to all his doctors who supported him and his mom during this journey, and to his many supportive fans on Facebook/MyPomPals(9).

Jill M. Patt, DVM

You may also like to learn more about Tracheal Collapse in Dogs

References:

1. Wikivet -https://en.wikivet.net/Trachea_-_Anatomy_%26_Physiology
2. Veterinary Partner -https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951968
3. Hycodan on Veterinary Partner- https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951401
4. Desert Veterinary Medical Specialists -http://www.dvmspecialists.com
5. VCA Animal Referral and Emergency Center of Arizona - http://www.vcaspecialtyvets.com/animal-referral-arizona/
6. Article Reference: Tracheal Collapse: What Are The Options? Atlantic Coast Veterinary Conference 2012, Don R. Waldron, DVM, DACVS, Oquendo Center, Las Vegas, NV
7. Southwest Veterinary Surgical Services: Tara M. Enwiller, DVM, MS, Diplomate, ACVSIR:
8. Article Reference: Evolution of the Tracheal Stent International Veterinary Emergency and Critical Care Symposium 2013, Matthew W. Beal, DVM, DACVECC, Michigan State University, East Lansing, MI, USA
9. My Pom Pals - https://www.facebook.com/mypompals
10. (10) Video of Wookie’s Bronchoscopy -https://www.facebook.com/mypompals/videos/vb.404127793045987/753012911490805/?type=2&theater
11. (11)Video of Wookie’s stent placement - https://www.facebook.com/mypompals/videos/vb.404127793045987/753015054823924/?type=2&theater
12. (12) Trainers - Club-Doggie http://club-doggie.com/