Comments on grading system for epiglottic structure

This letter concerns the study¹ published in the March 15, 2010, issue of JAVMA titled “Endoscopic evaluation of arytenoid function and epiglottic structure in Thoroughbred yearlings and association with racing performance at two to four years of age: 2,954 cases (1998–2001).”

In the report, the authors describe systems for grading arytenoid function and epiglottic structure. My comments concern the grading system for epiglottic structure. In this system, grades ranging from 0 to IV were assigned on the basis of thickness, length, and edge definition of the epiglottis. A grade of 0 was considered normal, and a grade of IV was described as thin, short, and flaccid.

This system assumes the epiglottis is a static structure. I and others have observed that the epiglottis is not a static structure and that, in fact, the apparent size, rigidity, and texture can change. In a study² evaluating the hyoepiglotticus muscle, Holcombe et al stated that “…electrical stimulation of the hyoepiglotticus muscle caused conformational changes in the epiglottis of 3 of 6 horses. As the epiglottis pressed ventrally against the soft palate, its edges rolled slightly inward, and the epiglottis developed a concave shape similar to that described as dynamic epiglottis hypoplasia or epiglottic flaccidity.” Of interest, that report also details findings on dissection of the hyoepiglotticus muscle. In horses, this muscle originates on the basihyoid bone and inserts on the ventral surface of the epiglottis. In adult horses, this is an area 12 to 15 mm in length in the long axis and 8 to 10 mm in width.

Another report³ describes the dynamic changes in the epiglottis in an 18-month-old Quarter Horse filly. The authors documented that the epiglottis appeared small and flaccid on initial examination but after administration of xylazine, appeared normal in tone and size.

In my experience, I have identified other yearlings that appeared to have a small, flaccid epiglottis without a serrated edge. These horses were being examined with restraint such as a twitch or lip chain, as were the horses in the study by Garrett et al.¹ These horses appeared anxious, and I found that when they were given a low dose of xylazine and reexamined without restraint, the epiglottis would appear rigid and have the dorsal curve, rigidity, and serrated edges that are described as normal in the report.

In conclusion, the dynamic nature of the appearance of the epiglottis should be considered when it is evaluated during prepurchase examinations.

Richard Estes, dvm

Ocala, Fla

The authors respond:

The authors thank Dr. Estes for his thoughtful comments. We agree that the epiglottis is not a static structure and that its appearance may change over time or may vary depending on the conditions under which the patient is examined. Many veterinarians are critical of the upper airway in yearlings that have an epiglottis that appears to be smaller and more flaccid than typical. One of the goals of our study was to evaluate whether these differences in structure affect racing performance. This required some method of categorizing the different appearances of the epiglottis. The authors agree that the method used in this study was not perfect and did not take into account the structural changes that can and do occur, but considering the number of horses evaluated, our results provide support to the conclusion that the horses with grade III or IV epiglottic structure should be viewed with caution.

When evaluating the upper airway, veterinarians should always consider the conditions under which the examination is performed, meaning the behavior of the horse, the type of restraint used, the response of the horse to the restraint used, and even the position of the head and neck during the examination. Each animal in this study was examined once, so our data represent a single point in time, and we did not attempt to determine how different conditions may have affected the appearance of the epiglottis in individual horses. These yearlings were all examined under similar conditions at a public auction with a nose twitch or lip chain used for restraint. Our aim was to provide practitioners with useful information when performing prepurchase examinations under these conditions.

In a practical sense, the authors recommend that if an abnormality is observed during the standard upper airway examination, the examination should be extended to allow the appearance of the epiglottis to return to normal. Additionally, the method of restraint can be changed (eg, removing the twitch, using a lip chain, or using no restraint beyond a lead shank). If a thorough examination cannot be performed, horses may be reexamined later in the day or the following morning. In some fractious individuals for which an adequate opinion cannot be rendered, many consignors will allow for a follow-up examination in the evening after administration of a tranquilizer. In our opinion, our results suggest that veterinarians may want to exercise caution when confronted with a yearling with grade III or IV epiglottic structure.

Katherine S. Garrett, dvm

Scott W. Pierce, dvm

Rolf M. Embertson, dvm, dacvs

Rood and Riddle Equine Hospital, Lexington, Ky.

Arnold J. Stromberg, phd

Department of Statistics, College of Arts and Sciences, University of Kentucky, Lexington, Ky.

More on medical advances and the client's budget

I thoroughly applaud Dr. Karen Detweiler's letter to the editor¹ in the April 15, 2010, issue of JAVMA. In many respects, I feel the same way she does and would like to offer my point of view. I have used my experience from years of practice to look for patterns of disease that I can diagnose and treat as efficiently as possible. If it becomes clear that options will run out by exhausting funds on testing, I believe we have an obligation to provide as efficient treatment as possible and avoid euthanasia for reasonably treatable problems. We should also remember to do no harm and not take our clients' trust in us for granted. Dr. Detweiler's comments point to the fact that we have standards and values that may differ between us. As we move through our practicing careers, our ideas may change. When we are younger and less confident, every disease is new to us. With more experience, we are able to more adequately communicate with owners regarding the ups and downs of treating disease. We could explain our actions at any moment for any number of reasons, but each of us should use our lessons from practice and life to gravitate toward practicing from the heart.

For some pet owners, our fees are a huge strain, whereas others never give them a thought. Each of us learns to provide a level of service that fits for most of our clientele. I think we all become frustrated with the realization that sometimes it is not about access to money but rather a lack of priority in our client's eyes. It is also disheartening to realize that sometimes we may care for an animal's life more than a pet owner does. Surely as animal advocates, we should be proud that we are at least willing to try. I know many veterinarians who go above and beyond in helping animals when they are abandoned. I am proud to be a veterinarian and to be associated with a profession that shows such resource and tenacity. It is easy to believe that with the advent of progress, things are getting out of hand, but this is not unique to our profession. There are those within our profession who will have different standards and values, but as long as there are veterinarians who are willing to practice true to their hearts, there will be clients who find a veterinarian who suits their needs.

I do not know Dr. Detweiler but would send her this message: you are not alone, and I am proud to feel the same way you do and am glad to share my feelings on this issue. Rather than getting caught up in other veterinarians' actions, I think it is more rewarding to focus on our patients. After all, if the roles were reversed, would a dog turn away a human who could not pay?

Callum W. Hay, bvms

Tampa, Fla.