Canine Digestive Tract Disorders in Several Breeds (Part 2)

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Torsion

 

Commonly called bloat, sometimes described as gastric dilation/volvulus (GDV), this is a terrifying and frequently fatal disorder that German Shepherds and many other deep?chested dogs experience. A twisting of the entrance and exit to the stomach traps the food and gas. As the stomach swells, the twist is more unlikely to be relieved without veterinary help. Great strides in surgical treatment have been made, but the key to reducing the high mortality is still time. Recognize the symptoms and get the dog to a veterinary surgeon, preferably an emergency or trauma-oriented hospital. Simple dilation (swelling due to gas) may not be serious as long as the dog is able to pass food into the duodenum, but it has been estimated that 80 percent of all dogs that experience simple dilation will someday also have torsion.

 

Symptoms of torsion include a swollen, turgid abdomen; the sluggish action of the dog; his white, frothy, unsuccessful attempts at vomiting; and perhaps his scratching in the dirt to make a cool hole in which to lie down. Also, the spleen will feel like a hard lump. The spleen is normally wrapped around some of the stomach and therefore splenic torsion usually accompanies gastric torsion, sometimes occurs without stomach torsion. When either happens, the return of the blood that flows through the spleen is shut off, causing shock, the “immediate” killer.

 

The first thing your vet is likely to do is attempt to push a tube down the throat into the stomach so the gas pressure can be relieved. If he cannot get past the twisted part of the alimentary canal, he may opt for immediate surgery so he can untwist the organs. One emergency veterinary service in the Detroit area uses a different kind of lavage tube in their treatment of acute torsion. The large diameter, stiff, black polyethylene pipe has a smaller, flexible tube inserted into it. This smaller tube is for warm water so that the stomach contents can be flushed out of the larger one for about fifteen minutes. In either case, once the dog has been stabilized, decisions can be made about whether to operate, or untwist a stomach or spleen still in volvulus.

 

Follow?up surgical techniques are numerous, but perhaps the one with the most success in preventing future torsion is a tube gastrostomy. In this procedure, a rubber or vinyl tube is put into the stomach through the abdominal wall, and in a week the stomach wall at that point becomes attached with scar tissue to the peritoneum and abdominal wall. The tube is then pulled out. The surgical opening seals off in a few days, and since the stomach is fused to the abdominal wall, it is prevented from again twisting out of position. Regular gastroplexy, which is suturing the stomach to the abdominal cavity, is also widely performed. Because of these and other techniques, especially the rise of emergency clinics, the mortality rates among those that make it to the clinic while still alive has plummeted to about 15 percent. Another 15 percent or so die without being seen by the vet first.

 

Groups of scientists at many locations have been studying bloat for a long time, partly with help from such as Morris Animal Foundation, the GSDCA, and many others. So far, they have identified a number of likely causative factors, including behavioral traits.Breed susceptibility is pretty obvious, with 25 percent or more of Great Danes, Saint Bernards, Weimaraners, and Irish Setters expected to suffer from bloat sometime during their lives. German Shepherd Dogs, Standard Poodles, Collies, and Gordon Setters are fairly high on the incidence lists, also. Some of the characteristics seen most often in dogs that had bloated include some stressful event, even minor, in approximately the eight hours prior to the incident, a fearful temperament, and consumption of fairly large quantities of non-food material. The only dogs I’ve had direct contact with that bloated were of impeccable character, but those may have been in the minority. Purdue researchers found no pattern in presoaking dry food or not, but a slight correlation between several smaller meals and less bloat. Others found no relation to soybean meal in the food, an early target of breeders looking for a primary cause. Adding vegetables and canned or meat scraps appears to help lower incidence. Most dogs (60%) bloated not immediately after vigorous exercise soon after a meal, but in mid- to late evening when resting or sleeping.

 

Less likely are other types of torsion, but they can be as life-threatening. Splenic torsion can occur without gastric twisting, and an even more rare disorder is mesenteric root torsion. The mesentery is the white, fibrous, web-like or film-like tissue that connects the various sections of intestines to each other and to the abdominal wall.Blood vessels travel through the mesentery, and if there is a twisting there, regardless of whether the intestine itself is closed off, the blood supply can be halted and the intestinal tissue can become necrotic. Bloody diarrhea, vomiting, abdominal swelling and/or pain, and shock or general collapse can be symptomatic. It may be the same as what some call “twisted intestines”. So few dogs survive that it is impossible to prevent recurrence or conclusively predict whether those are at greater risk for another attack than any other dog is.

 

There is a familial element in torsion/volvulus in many, similar to the way cancer “runs in families”, but most cases don’t give much of a clue to hereditary factors. As in “toxic gut syndrome” which is also seen a lot in some GSD lines, it is almost impossible to tell which came first, the presence of abnormal bacterial populations and irritated intestinal or stomach linings, or the bloat itself.Which is cause and which is effect is not going to be easy or even possible to determine. Some investigators suspect that breeders may be stuffing their small, young puppies’ stomachs too much, with results that show up only later in life. Work goes on. Dr. Larry Glickman and his group at Purdue University as well as others have published several papers on this syndrome. Dr. Glickman commented that the supposed claim that raised food bowls are correlated with increased incidence in torsion/bloat may just mean that this allows a dog to swallow more food (and air?) more quickly than if they were on the floor. A couple of website references, such as <http://www.vet.purdue.edu/epi/bloat.htm>, had some info, including from JAVMA’s Nov 15, 2000 issue. An abstract follows:

 

Canine Gastric Dilatation-Volvulus (Bloat)

School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907-1243

Non-dietary risk factors for gastric dilatation-volvulus in large and giant breed dogs.Lawrence Glickman, VMD, DrPH;N.W. Glickman, MS, MPH; D.B. Schellenberg, MS; M. Raghavan, DVM, MS; T. Lee, BA

Summary of findings: (references 1 & 2) A 5-year prospective study was conducted to determine the incidence and non-dietary risk factors for gastric dilatation-volvulus (GDV) in 11 large- and giant-breed dogs and to assess current recommendations to prevent GDV. During the study, 21 (2.4%) and 20 (2.7%) of the large and giant breed dogs, respectively, had at least 1 episode of GDV per year of observation and 29.6% of these dogs died. Increasing age, increasing thorax depth/width ratio, having a first degree relative with a history of GDV, a faster speed of eating, and using a raised feed bowl, were associated with an increased incidence of GDV. The table below summarizes the magnitude and direction of GDV risk associated with having each of these factors. The relative risk (RR) indicates the likelihood of developing the disease in the exposed group (risk factor present) relative to those who are not exposed (risk factor absent). For example, a dog with a first degree relative with a history of GDV is 1.63 times (63%) more likely to develop GDV than a dog without a history of GDV. As another example, if dog ‘A’ is a year older than dog ‘B’, then dog ‘A’ is 1.20 times (20%) more likely to develop GDV than dog ‘B’.

 

 

 

Risk Factor

Relative

Risk

Interpretation

Age

1.20

20% increase in risk for each year increase in age

Chest depth/width ratio
(1.0 to 2.4)

2.70

170% increase in risk for each unit increase in
chest depth/width ratio

First-degree relative with
GDV(yes vs. no)

1.63

63% increase in risk associated with having a
first-degree relative with GDV

Using a raised feed bowl
(yes vs. no)

2.10

110% increase in risk associated with using a
raised food bowl, contrary to popular opinion!*

Speed of eating (1-10 scale)
[for Large dogs only]

1.15

15% increase in risk for each unit increase in
speed-of-eating score for large dogs

*studies may be ongoing to clear up this concept.

 

Most of the popular methods currently recommended to prevent GDV did not appear to be effective, and one of these, raising the feed bowl, may actually be detrimental in the breeds studied. In order to decrease the incidence of GDV, we suggest that dogs having a first degree relative with a history of GDV should not be bred. Prophylactic gastroplexy appears indicated for breeds at the highest risk of GDV, such as the Great Dane. [Gastroplexy is a procedure that by surgery and scar tissue formation affixes various surfaces to each other to reduce chance of twisting.]

 

OBJECTIVE: To identify non-dietary risk factors for gastric dilatation-volvulus (GDV) in large breed and giant breed dogs.
DESIGN: Prospective cohort study.
ANIMALS: 1,637 dogs 6 months or older, of the following breeds: Akita, Bloodhound, Collie, Great Dane, Irish Setter, Irish Wolfhound, Newfoundland, Rottweiler, Saint Bernard, Standard Poodle, and Weimaraner.

PROCEDURE: Owners of dogs that did not have a history of GDV were recruited at dog shows, and the dog’s length and height and the depth and width of its thorax and abdomen were measured. Information concerning the dog’s medical history, genetic background, personality, and diet was obtained from the owners, and owners were contacted by mail and telephone at approximately 1-year intervals to determine whether dogs had developed GDV or died. Incidence of GDV, calculated on the basis of dog-years at risk for dogs that were or were not exposed to potential risk factors, was used to calculate the relative risk of GDV.

RESULTS AND CLINICAL RELEVANCE: Cumulative incidence of GDV during the study was 6% for large breed and giant breed dogs. Factors significantly associated with an increased risk of GDV were increasing age, having a first-degree relative with a history of GDV, having a faster speed of eating, and having a raised feeding bowl. Approximately 20 and 52% of cases of GDV among the large breed and giant breed dogs, respectively, were attributed to having a raised feed bowl.[end of abstract]

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Another article based on the same research but with slightly different data pulled out for the particular subject matter, was published in 1997: Multiple risk factors for the gastric dilatation-volvulus syndrome in dogs: a practitioner/owner case-control study (by): Glickman LT, Glickman NW, Schellenberg DB, Simpson K, Lantz GC. JAAHA, May-Jun., 1997.ABSTRACT: A study was conducted of 101 dogs (i.e., case dogs) that had acute episodes of gastric dilatation-volvulus (GDV) and 101 dogs (i.e., control dogs) with non-GDV-related problems. The control dogs were matched individually to case dogs by breed or size, and age. Predisposing factors that significantly (p less than 0.10) increased a dog’s risk of GDV were male gender, being underweight, eating one meal daily, eating rapidly, and a fearful temperament. Predisposing factors that decreased the risk of GDV significantly were a “happy” temperament and inclusion of table foods in a usual diet consisting primarily of dry dog food. The only factor that appeared to precipitate an acute episode of GDV [in their observations] was stress.

 

This contradicted the early-1990s study that indicated the opposite: that raised bowls should reduce the incidence of torsion/bloat. An article in “Bloat News” indicated a possible link that raised feeders might help prevent future episodes in a dog susceptible to “aerophagic” bloat (linked to swallowing too much air with the food, a commonly blamed cause at the time. Another issue of the same periodical indicated the single highest correlating factor was morphology (body type).A graph showed a sharp incidence increase as the depth of the chest exceeded its width and a strong correlation with body condition and temperament (weak nerves vs. calm, unstressed dogs). It may be good to select dogs that have strong, calm nerves, and are not slab-sided!

 

An article on the Foster and Smith Pet Education site, “Interpret Findings of a New Study on Bloat (Gastric Dilatation/Volvulus – GDV) with Caution”, December 2000, at: <http://www.peteducation.com:80/article.cfm?cls>, starting with a subheading, “The Question of Raised Food Bowls” circulated among fanciers. An excerpt: “In this study, when analyzing the association between the rate of GDV and the height of the food bowl some questions arise. First, the study found that large breed dogs whose food bowls are not elevated have the lowest risk of GDV. A confusing finding is that large breed dogs who have their bowl raised more than 1 foot have the next lowest risk, and those who have their food bowl raised somewhere between the floor and one foot have the highest risk. So, the risk of GDV is not proportional to the height of the food bowl. If height of the food bowl is important, why doesn’t the risk steadily increase, the higher the food bowl is raised? Secondly, it appears that the researchers did not consider the height of the animal in relationship to the height of the bowl when looking for an association between food bowl height and prevalence of GDV. It would be of interest to compare the height of the bowl to the height of the dog, since dogs in this study varied widely in height due to breed differences and age (some were only 6 months old).

 

“The third question is, ‘Why weren’t similar findings obtained in giant breed dogs?’ In giant breeds, dogs with food bowls raised less than one foot had the same incidence of GDV as those dogs who did not have their dishes raised at all. Finally, it is unclear if the researchers also analyzed whether the elevated feeders were being used because other medical problems were present or if the elevated feeders could influence other factors such as the speed of eating. Could these medical problems or other factors, rather than the elevated feeders, have contributed to the increase in GDV in this group?A second subheading was ‘Comparison to Other Studies’. The results of this study agree with most previous studies, which also found that GDV increases with age. On the other hand, in several studies, dogs who ate faster had higher rates of GDV. In this study, we had a peculiar finding: eating at a fast rate was associated with an increased rate of GDV in large breed dogs, but a decreased rate in giant breed dogs. There have been other contradictory findings in research on GDV. In some studies it was found that overweight dogs had higher rates of GDV, and in other studies, lean dogs had higher rates. In this study, weight did not seem to make a difference. In most studies, including this one, the rate of GDV between males and females were similar; in one study, however, males had an appreciably higher rate.”

 

One other item that was brought to light on a “VetMed” e-mail discussion list, was that there is no proven advantage to raised feeders, and that the Foster and Smith company which runs the Pet Education website sells many types of elevated feeders.

 

While some excellent work on GDV has been carried out at Purdue, some feel that very insufficient research has been done in the US on canine torsion/volvulus. Here are websites I was told will give information on GDV; I have not checked these out, so I cannot verify their usefulness. Some may be “foreign links, as well as human links and livestock links” as the person who gave me this list said. Many may be obsolete by the time you read this, so do some additional websearches.

http://www.editoraguara.com.br/cv/ano5/cv29/cv29.htm#tormes

http://www.vetinfo.com/dbloat.html#MesentericVolvulus

http://www.canismajor.com/dog/bloat.html

http://www.harkleen.com/Chimo.htm

http://www.f-v-s.com/newsletters/vol1no2emergency.htm

http://web.missouri.edu/~vmicrorc/Nematoda/Strongylids/Strongyles/Svulgaris.htm

http://search.atomz.com/search/?sp-q=mesenteric&sp-a=000608a5-sp00000000

http://www.aevedi.org/00121CV.htm

http://www.emedicine.com/emerg/topic311.htm

 

The huge retrospective epidemiological study of GDV, as I mentioned above, is at Purdue, run by Larry Glickman.<http://www.vet.purdue.edu/epi/bloat.htm>The project was funded by the AKC Health Foundation and by breed clubs.

 

postscript on torsion/bloat/GDV: Bonnie Dalzell <bdalzell@QIS.NET> in an 11 Nov 2008e-mail post re GVD-Bloat, said, “There is a lot on the internet about bloat. Purdue University has/had a long-running epidemiological study. Dr Armstrong in Canada had a canine genetics website with a lot of information about bloat in poodles. See these two links:http://www.addl.purdue.edu/newsletters/2005/Summer/canine-acd.htm
http://www.mysticalpoodles.com/poodle-breeders-recommend/article11.html
Unfortunately, some online links for Glickman’s work seem to have “gone away.”I wonder why the Bloat Information site was closed down by Purdue. I did find these pages (wayback machine): http://web.archive.org/web/ ; /http://www.vet.purdue.edu/epi/bloat.htm .And here is the link to Dr Armstrong’s site:http://www.canine-genetics.comI looked over the articles on that site. A number of them are not hosted on the site but are links to now vanished pages. There are a number of things one can do to try and find these articles. First is to check to see if the internet archive has saved the pages (Internet archive or “wayback” machine). http://www.archive.org/index.php Another is to Google the author’s name and the title of article; many other sites may also host them. Websites go away when people die or lose interest in the topic, yet the information may still be of use.” Bonnie

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