Canine Gastric Dilatation-Volvulus (Bloat)
School of Veterinary Medicine
Purdue University, West Lafayette, IN 47907-1243
BLOAT NOTEs
News from the Canine Gastric Dilatation-Volvulus Research Program
Phone: (765) 494-6301 FAX: (765) 494-9830
January, 1997
EPIDEMIOLOGY PROGRAM RESEARCH TEAM
Department of Veterinary Pathobiology
Larry Glickman, VMD, DrPH
Diana Schellenberg, MS
Tana Lee
Department of Veterinary Clinical Sciences
Gary C. Lantz, DVM
William R. Widmer, DVM, MS
Center for the Human-Animal Bond
Nita Glickman, MS, MPH
Enrollment in Prospective Study of Risk Factors Tops 1500
Enrollment of show dogs in the ongoing prospective study of bloat risk factors has climbed to 1507 and is heading toward the target of 2,000. The enrollment period for the 10 breeds in the study has been extended through March 1997 to allow the Purdue investigators to attend large specialty shows in California. As far as we know, this is the largest prospective study ever conducted in companion animals, both in terms of the total expected enrollment and the length of follow-up (up to 4 years for some Irish Setters and Great Danes that were enrolled in 1994).
The study is intended to evaluate (a) the incidence of bloat in each participating breed; (b) the relationship between body conformation and bloat risk in individual dogs within a breed; (c) the influence of family history of bloat on bloat risk; and (d) whether diet and personality characteristics are predisposing factors for bloat. Dogs are measured and enrolled at a show. Then the owner completes a Current Status and History Questionnaire to provide baseline information about the dogís diet, temperament, etc., and the dogís health status is followed over time to see which dogs bloat and which remain bloat-free.
Table 1 lists the number of dogs in each of the 10 breeds enrolled as of November 14, 1996. This table also shows the bloat risk of each breed relative to the risk in mixed-breed dogs, who are arbitrarily assigned a risk of 1.0. Thus the breed risk of 41.4 for the Great Dane implies that Danes are 41 times more likely to bloat as mixed-breed dogs. The breed risk comparisons are based on retrospectively collected data from an earlier Morris Animal Foundation-sponsored study of 1,934 dogs with bloat and 3,868 without bloat (LT Glickman et al.: J. Amer. Vet. Med. Assoc. 104:1465-1471, 1994). Earlier comparisons based on these data included only the more common breeds. Table 1 includes 3 less common breeds which are part of the ongoing prospective study, i.e., Akita, Bloodhound, and Irish Wolfhound.
Table 1
|
|
Number Enrolled | Breed Risk of Bloat* |
| Great Dane | 220 | 41.4 |
| Irish Wolfhound | 182 | 38.4 |
| Bloodhound | 128 | 25.6 |
| Saint Bernard | 127 | 21.8 |
| Weimaraner | 84 | 19.3 |
| Akita | 89 | 16.4 |
| Irish Setter | 228 | 14.2 |
| Standard Poodle | 131 | 8.8 |
| Collie | 212 | 2.8 |
| Rottweiler | 106 | 1.1 |
| Total Number Enrolled | 1507 |
Negotiations are underway with the AKC Canine Health Foundation to expand the study to 11 breeds by adding the Newfoundland in March 1997 and extending their follow-up through 1998.
Success of the prospective study ultimately depends on the participating breed clubs, i.e., the owners' willingness to have their dogs measured and enrolled at the remaining specialties, cooperation in completing the questionnaire with baseline data that is essential to the study, and willingness to provide follow-up information on the health status of their dogs. Completed questionnaires are rolling into Purdue, and the data are being entered into the computer. We are very grateful to the owners who have completed their questionnaires. A reminder postcard was sent to non-responding owners in September, and those still unheard from are being "hounded" in a phone reminder campaign.
An Epidemic of Gastric Dilatation-Volvulus (GDV, Bloat) in the US?
There are no reliable population-based estimates of the incidence of GDV in dogs. However, a large computerized multi-hospital record system, the Veterinary Medical Data Base (VMDB), indicates that the frequency of GDV in dogs seen at veterinary teaching hospitals in the US has increased dramatically from 0.036% of all hospital admissions of dogs in 1964 to a peak of 0.57% in 1994, an increase of approximately 1500% (see Figure 1 below). This increase is unlikely to reflect changing diagnostic criteria or disease recognition. The increasing frequency of GDV starting about 1969 affected most of the large and giant dog breeds. Therefore, it is also unlikely to be caused by genetic factors. However, this apparent epidemic of GDV could be explained by introduction of one or more novel environmental factors such as a new ingredient in dry dog foods or a change in the manufacturing processes. It might also be related to changes in canine vaccines or their pattern of use, e.g., multivalent vaccines. Epidemiologic studies will be required to identify the causes of this bloat epidemic in the US and to monitor future trends. Keep in mind that despite appropriate veterinary medical care, approximately 25% of all dogs with GDV will die of the disease.
BLOAT NOTEs Goes High Tech in Cyberspace
You can now access BLOAT NOTEs from the World Wide Web! Some people may ask, "What is the World Wide Web?" It is a subset of the Internet -- so-- "What is the Internet?"The Internet is a series of interconnected computer networks from all over the globe. Computers can "talk" to each other because they use the same communications protocol: TCP/IP (Transmission Control Protocol/Internet Protocol). Through the Internet, we can use electronic mail (e-mail), log-on to other computers connected to the Internet, and transfer files from these "host" computers to our own computer.
The World Wide Web is a subset of the Internet where you can view documents that not only have text, but also graphics, video, and audio. Documents on the World Wide Web have "links," usually underlined and blue in color, that allow you to click and connect to other documents or maps or movies, etc. Each document in the World Wide Web has an "address." The address of the web page which contains links to BLOAT NOTEs is: http://www.vet.purdue.edu/depts/vad/cae
This web page is titled Center for Applied Ethology and Human-Animal Interaction. Under "Research Programs," you will see links to Canine Gastric Dilatation-Volvulus (Bloat), which describes Purdue University's bloat research program and links to several BLOAT NOTEs issues. To "surf" the World Wide Web, you need a "web browser." This software allows your computer to access the World Wide Web through your Internet connection. The most popular web browsers are Netscape Navigator (from Netscape Communications) and Internet Explorer (from Microsoft). We will be continually adding information to our web page about Purdue's bloat research project and the most current issue of BLOAT NOTEs as soon as it is available.
Here are a few other addresses of interesting animal-related web pages: http://www.vet.purdue.edu (Purdue University School of Veterinary Medicine)
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Here are a few other addresses of interesting animal-related web pages: http://www.vet.purdue.edu http://netvet.wustl.edu http://www.akc.org http://www.sandiegozoo.org |
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HAPPY SURFING !!!!
A Message to Dog Owners from the Director of the Purdue Bloat Research Program
Several times a week I receive a phone call from someone whose dog has died of bloat. Usually my role is to provide a sympathetic ear and assure the callers that there was nothing they could have changed to prevent the incident. Our current knowledge of bloat does not allow us to identify specific events that ìtriggerî an acute episode in susceptible dogs, although some form of "stress" was probably involved. One of our long-term research objectives is to better define what constitutes stress for dogs and to measure their physiological response to it. However, the primary goal of the research is to determine why some dogs are more susceptible to bloat than others, i.e., what are the risk factors for bloat. This has led to studies of the physical conformation of dogs, their diet, vaccination histories, and even to new ways to evaluate a dogís temperament and personality.The overall bloat fatality rate approaches 30% for dogs with a dilated, rotated stomach. Approximately half of the dogs that die with a rotated stomach will do so before veterinary medical or surgical treatment is obtained. Dogs may be found dead or die on the way to the hospital, or may be euthanized by the veterinarian because of their poor prognosis or the owner's financial considerations. In contrast, dogs properly treated have >80% probability of surviving a bloat episode and then leading a normal life. Veterinarians over the past 2 decades have reduced dramatically the postoperative fatality rate from gastric dilatation-volvulus (GDV) from >50% to <20% by using improved therapy for shock, safer anesthetic agents, and better surgical techniques.
Too often, however, owners of dogs that died of bloat tell me that they had recognized that the dog had a serious problem and rushed the dog to a veterinarian, only to be told that it was probably only a "belly ache," or that the dog's stomach was dilated, but not rotated. Sometimes the veterinarian recognized dilatation, but not a rotation (volvulus, torsion), passed a stomach tube to relieve the pressure, and sent the dog home. Or the dog was diagnosed as having dilatation and rotation, and a stomach tube was passed to relieve the pressure, but surgery (gastropexy) to permanently correct the rotation was delayed, either because the dog was thought to be too ill to withstand the surgery, or the veterinarian was not adequately equipped or prepared at the time to perform the operation. The latter may occur if the veterinarian is in the midst of busy office hours or if -- especially at night -- there is insufficient technical help available to properly perform the surgery, which requires careful administration of anesthesia, appropriate fluid therapy, and close monitoring of the dog's vital signs.
Numerous clinical reports from Europe and the United States show that gastropexy to prevent gastric rotation should be performed as soon as possible following stomach decompression on all dogs with gastric dilatation, whether or not the stomach is thought to be rotated at the time. The recurrence rate of gastric volvulus in dogs treated for bloat conservatively, i.e., without surgery, approaches 100%, whereas the recurrence rate following gastropexy is <5%. The stomach of a dog that has had a gastropexy can still dilate, but it is unlikely to rotate, so if dilatation does occur after gastropexy, it can probably be treated conservatively.
What does all this mean to you? If your dog suddenly develops a distended abdomen, appears uncomfortable, and gets progressively worse, rush the dog to a veterinarian, preferably one equipped to do emergency surgery. Gastric distention is a life-threatening condition, even if the stomach has not rotated. Immediate decompression is required to relieve pressure on blood vessels and to restore circulation to the heart, because shock can occur within minutes of the first clinical signs. Fluid therapy is indicated to treat shock, and drugs may be needed if the heart rhythm is irregular. This should be followed as soon as possible by surgery to reposition and immobilize (gastropexy) the stomach before it is irreversibly damaged. The best indicators of how well the dog will do postoperatively are its physical condition (state of shock) prior to surgery and the appearance of the stomach during surgery (since dead or dying stomach tissue implies a very poor prognosis). Intensive monitoring is usually required for several days postoperatively in case complications occur.
If you suspect your dog has bloat, but the veterinarian dismisses it as a minor problem, inquire about radiographs to rule out GDV. If dilatation with or without volvulus is diagnosed and the stomach is decompressed, either by passing a stomach tube or by piercing the stomach with a large needle (trochar) passed through the body wall, the dog should be considered as a candidate for immediate surgery, unless its condition is too unstable to tolerate anesthesia. If the veterinarian recommends that surgery be delayed for any other reason, seek a second opinion immediately. Delay in surgery will increase the chance of the stomach rotating if it hasnít already, or will decrease the chance of the dog surviving if rotation has occurred.
Following is an excerpt of a letter that illustrates some of these points.
Chicken
bone? I watched her and we continued to walk. She was happy and greeted
people, wagging her tail, ... and had fun. We went home and Kelly went
upstairs where she attempted to vomit several times. I immediately called
my vet. Kelly and I arrived at the veterinarianís office within five minutes
of the phone call. I told the veterinarian that Kelly had vomited two
or three times with nothing coming up. I said that she looked a little
broad around the ribs. The veterinarian did a physical examination and
concluded that Kelly's problem was just a "stomach ache." ...
I was directed to give her Pepto Bismol®. I took Kelly home and she lay
down on the bed. About 45 minutes later she went out to the back yard.
When I went out 10 minutes later, I found her bloated up. I grabbed her,
took her back to the veterinary hospital, but she died on the operating
table."
Life after Bloat -- Elly's Story
(Editor's note: Elly's story was sent to us by Pauline Anderson. Elly, who was in Purdue's case-control study of bloat risk factors, underwent gastropexy. Her good post-bloat condition illustrates a typical outcome of prompt emergency treatment and gastropexy -- even to the point of competing at shows.)
"I'd like to share a happy experience I had with Elly, my Standard
Poodle, a bloat survivor. First, let me give a little history of Elly's
bloat incident. In November of 1993, Elly suffered 
full-blown
bloat twice in a 16-hour period. She was in a very serious condition and
the decision to go forward with surgery was the only one for Elly if she
was to survive. Elly was nine at the time of surgery. She is now twelve
and is enjoying a very happy life, although her tummy still has a tendency
to distend quite frequently. Fortunately this condition has proven to
be of little consequence and there doesn't seem to be any discomfort for
Elly, so we have learned to accept it.
Now, let me get to the subject that prompted me to write. On June 18, 1995, Elly earned her C.D. (Companion Dog Title) from AKC. She received a special award of a silver bowl for being the oldest qualifying dog at the trial. She also received awards for placing 4th and for being highest scoring Poodle in Novice A and B. Elly virtually began and ended her obedience career at eleven years young in less than 60 days, a full year and a half after her bloat experience. I want to say bloat is not always the end of the world, thank God, and there are still happy times to be had. Even special awards to be won." --Pauline Anderson
Honor Roll
We extend heartfelt thanks to all the individual dog owners and breed clubs for donations for Purdue's bloat research through the Morris Animal Foundation and the AKC Canine Health Foundation. These include the Akita Club of America, American Bloodhound Club, American Rottweiler Club, Collie Club of America Foundation, Irish Setter Club of America, Irish Wolfhound Club of America, Newfoundland Club of America, and Weimaraner Club of America. We wish it were possible to publish all the names on our honor roll of donors. Purdue has also received direct donations for bloat research from:
- Cleveland Collie Club
- Great Dane Club of Western Washington
- Irish Setter Club of Milwaukee
- Poodle Club of America
- Saluki Club of America (in honor of Ch. Ariel Sonova Drama of Hasten, owned by Cheryl R. Rosenberger)
In Memoriam
We are pleased to acknowledge memorial fund donations to Purdue's bloat research program in honor of:
- Vinnie, a Standard Poodle owned by Pat and Rose Essy (donation from Dianne Hopper)
- Misty Schott, pictured below, a German Shepherd (donation from Jan Ruggles)
Misty Schott
Epidemiologic studies of bloat and companion animal health problems by Purdue University School of Veterinary Medicine are made possible by contributions from the Morris Animal Foundation, AKC Canine Health Foundation, animal health companies, private foundations, breed clubs (national, regional, and local), and individual dog owners. We welcome your comments, suggestions, and support.
$$ Those wishing to donate can send contributions to Purdue University in care of Dr. Larry Glickman, Bloat Research Program, Veterinary Pathobiology VPTH 101, Purdue University, West Lafayette IN 47907-1243. If you are making a donation in memory of a bloat victim, and wish to have the dog's photo published in BLOAT NOTEs and on the World Wide Web, please indicate this when sending a photo.
Meet the Research Team --
Larry Glickman, VMD, DrPH, who directs the Purdue Bloat Research Program, is
Professor of Epidemiology and Environmental Medicine, Department of Veterinary
Pathobiology in the School of Veterinary Medicine at Purdue University.
Larry received his veterinary medical training at the University of Pennsylvania
School of Veterinary Medicine, and was a veterinary practitioner for several
years. Most of his career has been spent in teaching and research. After
earning his doctorate in Epidemiology and Public Health from the University
of Pittsburgh Graduate School of Public Health, he taught preventive medicine
and conducted epidemiologic research in the veterinary schools at Cornell
University and the University of Pennsylvania; he came to Purdue in 1988.
His broad
research interests, reported in books and >150 scientific papers, include
zoonoses, particularly roundworm (Toxocara) infections in dogs and humans,
rabies, and cat-scratch disease; parvovirus infection in dogs; heartworm
infection in dogs and people; the efficacy and adverse effects of canine
vaccines; nutritional requirements of dogs; distemper in dogs; cancer;
and pet overpopulation issues. Another strong interest has been the role
of pet animals and wildlife in identifying environmental hazards.
He has summarized this work as follows: "Risk assessment is the
process of characterizing the potential adverse health effects of human
exposures to environmental hazards. The important elements of risk assessment
are hazard identification, dose-response evaluation, exposure assessment,
and risk characterization. The traditional sources of data used in risk
assessment are findings of human epidemiologic research and laboratory
animal experiments. Because of the limitations of these approaches, we
have conducted epidemiologic studies in pet animals with naturally occurring
cancers to determine if the home environment is potentially hazardous
to both pets and their owners. We have shown that asbestos and insecticide
exposures of dogs in the home increases their risk of mesothelioma and
bladder cancer, respectively. Because the time between these exposures
in dogs and the onset of cancer is considerably shorter than for humans,
cancers in pet animals serve as sentinel diseases or early warning signals
of a hazardous home environment. We are in the process of establishing
a network of veterinarians to identify these veterinary sentinel health
events." 
We are also using several species of fish to develop biomonitoring methods to evaluate environmental contamination by toxic chemicals such as radioactive cesium and their potential to cause adverse health effects in humans, e.g., effects of the Chernobyl disaster."
Research on bloat in dogs has been a family affair for Larry and his wife Nita (profiled in the May 1993 issue of BLOAT NOTEs) since the late 1980s, when they first explored the use of the Veterinary Medical Data Base as a source of information about this disease. Both their son Seth, now in the MD-PhD program at the University of Pennsylvania, and daughter Danielle, a student at DePauw University in Greencastle, IN, have worked on various aspects of the research.
The Bloat Research Program at Purdue was launched in 1991 with case-control, survival, radiographic, and genetic studies of risk factors for bloat, funded by the Morris Animal Foundation. With funding from breed clubs, individual donors, and most recently the American Kennel Club Canine Health Foundation, the program has continued to grow. The goal remains the same: to help veterinarians and dog owners develop practical preventive measures to reduce the incidence of this disease. Larry realizes that, ìto accomplish our goal, many more years of hard work are still needed. However, he readily accepts this challenge as long as dog owners and breed clubs continue to give their support.