IN THIS NEWSLETTER:
Portosystemic shunts, or as they are commonly referred to, portocaval shunts, have been recognized as a cause of hepatic encephalopathy in dogs (and to a lesser degree in cats) for some time. Diagnosis of these shunts is based initially on a high degree of suspicion based upon clinical signs ranging from neurological abnormalities including seizures, to vomiting and diarrhea, to hypersalivation in cats. Many articles in both surgical texts, medical texts and the periodical literature give excellent reviews of the clinical signs and etiology of portocaval shunts. Those should be consulted for a comprehensive review of these symptoms.
Diagnosis initially was based upon finding elevated blood ammonia levels in symptomatic dogs, and upon exacerbation of symptoms being noted after a meal. Today, we have much more sensitive tests available including portal scintigraphy, ultrasonography, and contrast portography. Before any of these tests is considered, the definitive test today is demonstration of elevated serum bile acids. Both pre- and post-prandial blood samples should be obtained and your laboratory can instruct you on how to collect and interpret those based upon the normal values for that lab. Following the demonstration of elevated pre- and post-prandial serum bile acid concentrations in a clinically suspect case, a tentative diagnosis of portosystemic shunt can be made.
Initial management of these patients, in our practice, is done medically to alleviate the clinical signs prior to definitive surgical correction of the shunt. I use oral Neomycin (BiosolR) at a dose of 10-20 mg /kg TID, and Lactulose (CephulacR) orally at a dose of 15-30 ml TID-QID for dogs and 0.25-1.0 ml for cats. A low-protein diet is also used such as Hill's K/D. Clinical signs in most animals are greatly improved and medical management should be initially done for several days up to 2-3 weeks prior to surgery.
Surgical correction is the definitive treatment for portosystemic shunts. We initially do an exploratory surgical procedure and attempt to locate the abnormal vessel, rather than performing any other test such as portography or scintigraphy first; this is now the generally accepted standard procedure. If the shunt cannot be visualized, portography is then done. In the past, surgical correction has been a daunting procedure due to the complexity of accurately measuring the rise in portal pressure after ligation (or partial ligation) of the shunt. It has been my impression that pressure measurements are not repeatable and therefore invalid, and this has been confirmed after visiting with surgeons from different practices and universities at the recent ACVS meeting in Chicago. Until recently, we have not been doing shunt repairs in our practice for this reason. Currently available is a surgical implant which can be placed upon the shunt vessel and will produce gradual, complete occlusion of the shunt vessel, minimizing the potential for severe side effects in the immediate postoperative period. Intimate knowledge of the surgical anatomy is essential. We have been awaiting long-term follow-up after introduction of this procedure approximately 2 years ago, and it now appears that this is a safe and effective technique. Total shunt occlusion occurs over 30 to 60 days.
If you have an animal in which you suspect a portosystemic shunt is
present and you wish to obtain further information regarding possible surgical
ablation of the shunt, please call Dr. Dean at our office (918) 665-0508.
Several questions have emerged recently regarding the direction our surgical practice will take as it continues to grow. One of the more commonly answered questions is, "do you intend to merge with a corporate entity"? The answer to that question is an emphatic NO; we are committed to remaining independent of any group or corporate affiliation in order to provide our patients and you, our referring veterinarians, with the highest level of care while avoiding any appearance of conflict of interest.
We have also been asked to become mobile, or in other words to provide our surgical services at other practices. Our answer has been and will continue to be no to that question as well. The facility we currently occupy is now at the level where we can handle almost any surgical contingency, and overnight continuous care is available from the staff at the Animal Emergency Center for those cases requiring it. We feel that patient care would be compromised by a mobile practice and do not intend to incorporate that into our practice. We are also fortunate to have the ability to consult in-house with other specialists, as needed, to provide you with immediate access to state-of-the-art care for your cases.
In other news, many of you have heard of the new once-a-day anti-inflammatory and analgesic medication, EtogesicTM, from Fort Dodge. Information on that drug was posted to our internet site three or four weeks ago as advance notice of it's release was obtained. Further information on this new drug can be found in the Information for Veterinary Professionals section under 1998 Newsletters at www.vetsurg.com.
This promises to be an exciting new drug for veterinarians and for clients.
The American College of Veterinary Surgeons will be hosting it's annual Symposium and Surgical Forum in Chicago from October 8 - 11, 1998. Our practice will be closed Thursday and Friday; October 8-9, 1998. If you wish to schedule a surgical case, please leave a message on the answering machine as it will be checked at various times during the day and your calls can either be returned by the office secretary or your client contacted by our office. We will be back in the office Monday, October 12th.
Although a mailing will not be done, new developments from that meeting which might be of interest to you will be posted to our website.
Fort Dodge has just released it's new non-steroidal, anti-inflammatory (NSAID), Etogesictm (Etodolac). This new drug is a preferential inhibitor of the COX-2 enzyme, which is a distinct isoenzyme responsible for inhibition of cyclooxygenase-2, a potent mediator of inflammation. This preferential inhibition of COX-2 vs. COX-1 allows a margin of safety with Etogesic since it should have less effect on the kidneys and stomach, where the side effects of NSAID's which non-selectively inhibit cyclooxygenase occur.
Etogesic has been found effective for postoperative management of pain and inflammation and offers the distinct advantage of only requiring once daily administration orally. It is not affected by the presence of food within the stomach, therefore it may given with or without food.
Etogesic is going to be available in 150 mg and 300 mg tablets and the
dose range is from 10 to 15 mg/kg (4.5 - 6.8 mg/lb), given once daily.
Reported side effects in a study of 116 dogs where treatment was administered
for 8 days were:
As with other products, we will probably see additional precautions being issued as the number of clinical patients on this drug increase and other side effects may be recognized. Until large numbers of cases are out there and further conclusions can be made on the safety of this drug, it seem prudent to only use Etodolac as needed, rather than indiscriminately. At this time, however, the convenience of once daily administration of a potent anti-inflammatory and analgesic is enticing.
As with all medications, the manufacturer's recommendations should be read and followed.
Paul W. Dean, DVM
As has been seen in the human population, better health care leads to increased longevity, and therefore problems not recognized before are seen with greater frequency in the elderly. The same type situation seems to be occurring in veterinary medicine, in that with better veterinary care for pets, our companions are living longer and we are seeing problems in geriatric patients that were not recognized as commonly a few years ago. One of the syndromes that seems to be occurring more frequently is laryngeal paralysis.
My clinical impression is that we are seeing a much greater prevalence of laryngeal paralysis than in the past, especially in the Labrador retriever breed of dog. Several factors may be involved, including longevity, breed popularity, and a seemingly high prevalence of hypothyroidism in affected dogs.
Laryngeal paralysis should be suspected and included in the differential diagnosis of any dog with exercise intolerance, upper respiratory noise, and progressively worsening dyspnea with exertion. A complete work-up including CBC and chemistry panel as well as a heartworm check (occult) should be done. Conditions which might mimic laryngeal paralysis should be excluded based on radiographic and ECG studies as indicated.
The diagnosis of laryngeal paralysis can be made by direct visual observation of the laryngeal cartilages under very light anesthesia. Abduction and adduction of the laryngeal cartilages should be readily visualized as an active opening and closing of the glottis during respiration. Respiratory "flutter" during exhalation should not be confused with normal laryngeal function. The classic mid-position, fixed appearance of the laryngeal cartilages is often seen, and the larynx may appear edematous and thickened.
Treatment of laryngeal paralysis first involves identifying and treating any underlying endocrine or metabolic abnormalities. Medical treatment is not often satisfactory in alleviating respiratory distress, and surgical techniques aimed at increasing the lumenal diameter of the larynx have been developed.
NEW WEBSITE FEATURE
We have added a new feature to our internet site, www.vetsurg.com.
Under the "Information for Veterinary Professionals" section, we have a
Spotlight" feature of interesting and unusual clinical cases
seen here. I hope you will find this interesting as well as informative;
we plan to continually add new cases to this area on a routine basis. Our
periodic newsletters, which you have been receiving by mail, are also archived
on the website for your convenience. Due to increasing costs of printing
and postage, we plan to progressively scale back on the extent of our mailing
to only include our active, referring veterinarians. Access to new and
old brochures will still be available via the internet site.
EXTERNAL SKELETAL FIXATION
External Skeletal Fixation, or as most of us were taught, Kirschner-Ehmer devices, have been available to veterinarians for many years. There has been a recent resurgence in the use of these devices, as surgeons are finding that minimally invasive reduction of bone fragments combined with rigid fixation provides a more physiologically sound method of fixation for many fractures.
With this resurgence of interest in external skeletal fixation has also come useful information of proper application of these devices. Some of these advances available to veterinarians now include positive profile end-threaded pins with both cancellous and cortical design thread profiles, as well as centrally threaded pins for use in type II, or full pin fixation devices. One of the companies that has taken the lead in pin profile design and production is IMEX Veterinary, Inc. (1-800-828-IMEX).
A limitation in conventional application of external fixation devices has been trying to align pins when placing multiple pins in a type II, or full pin fixator configuration. "Hitting the clamp" on the opposite side of the bone was a major challenge, and all types of configurations for aiming, etc. have been proposed. Most surgeons, until recently, have abandoned the multiple type II configuration and utilized a modified type II pin placement, with only the top and bottom pins in the fixator being full pins, supplementing the midsection pins as half pins.
Recently, Securos, Inc. has developed an all-new aiming device along with special clamps which make application of type II KE's (fullpin fixators) much easier. It also allows the surgeon to place additional pinds as needed on the connecting bars without having to remove the apparatus and add clamps to the bar before placing additional pins. Securos' clamps snap onto the connecting bar and allow the placement of pins on an existing KE. Other advantages of this system include a method for predrilling pilot holes, measurement of pin depth, and placement of positive profile pins at all sites. I have been pleased with our trial of this system.
Contact Securos at (508) 347-8092 for more information on this innovative product.
Visit Us On the Web Many of you know us from our phone conversations about cases, and from our referral letters and brochures. We invite you to "come see us" at our website.
We are excited about this new project, and hope you will find valuable
information here which will benefit your practice and help you to better
serve your clients.
WELCOME NEW DOCTORS
This year brings some exciting new changes to Veterinary Medicine in Tulsa. As we enter our 5th year of service to the veterinarians in our area, we are pleased to be able to note that we now have, under one roof, an ophthalmologist, a surgeon, a dermatologist, and an oncologist/internist. This represents the only group of board certified and specialty trained veterinarians of this type in Northeast Oklahoma.
Most of you know Dr. Bob Gwin. Dr. Gwin has been coming to Tulsa for over 15 years, helping animals to see. Dr. Gwin does many procedures here in the Tulsa office, and phacoemulsification of cataracts at his central office in Oklahoma City. I believe I am correct in saying that Dr. Gwin is the only board-certified ophthalmologist in the state performing this procedure!
The Veterinary Surgical Referral Center continues to grow in number of cases seen each year. Being available from 8:00 a.m. to 5:00p.m. Monday through Friday, we have found that our referring veterinarians are very appreciative of our ready availability and the ease with which patients can be seen in an emergency.
Dr. Leslie Henshaw is now here two days a week, as a board certified veterinary dermatologist. Dr. Henshaw's practice is limited to dermatology on a referral basis only. Dr. Henshaw graduated from Oklahoma State in 1985 and was in private practice for 8 years. She finished a 3 year combined residency and Masters program at the University of Illinois in 1996 and was board-certified in dermatology in 1996!
The most recent addition here is Dr. Melinda Upton. Another Oklahoma State graduate, Dr. Upton did a one year rotating internship in a large private referral practice in Sacramento. Following her internship, she trained for two years in an oncology and internal medicine residency at the University of California - Davis. Prior to moving back to Tulsa, she practiced for 3 years in a large referral practice in suburban Detroit. She has been examined for board certification in oncology, and is currently awaiting the completion of her publication requirements to satisfy the final "hurdle" before attaining board-certified status. Dr. Upton is seeing both oncology and internal medicine referrals, and I can personally vouch for her expertise with the ultrasound unit!
All of these practices operate independently from each other, and we do not "cross refer" without consent from the referring veterinarian. Since we occupy space within the Animal Emergency Center, this provides a convenient central location with the added benefit of after-hours continuous care for our patients that need it. Our referring veterinarians appreciate the fact that we are in a neutral location, unaffiliated with any group or corporate practices.
Should you wish to consult with any of these doctors, the current numbers to reach them at are:
Dr. Dean (918)610-3569
Please do not hesitate to contact any of us should you have a question.