BLOAT / GASTRIC TORSION IN DOGS
Torsion of the stomach in the dog is characterized by life-endangering distension of the stomach with gas; the stomach is usually found to be severely dilated and congested, and often to have rotated about an axis in the plane of the esophagus.
There are many unknown features of this disease. Even the correct mane for the disease is not known. It is commonly called torsion of the stomach; however, many veterinarians, including the author, believe the primary condition is not torsion, but distension or dilation of the stomach with gas. This distension may or may not be followed by torsion or twisting of the stomach.
Incidence
Torsion of the stomach is seen most commonly in large breeds including the Great Dane and Bloodhound, as well as some of the intermediate size breeds. Most people agree it is a serious problem in the first-two named breeds. There does not appear to be any association with the sex or the age of the animal. It has been reported in young adults as well as fully mature dogs. There is no doubt it can occur suddenly after eating in a previously healthy dog.
The Cause of Torsion of the Stomach
A commonly expressed explanation is that the disease is purely a mechanical twist of the stomach. The stomach, containing some comparatively heavy food material, is pictured as swinging in a pendulum-like fashion. Then, as a result of a sudden jump from a high bench or from rolling or playing, the pendulum is swung completely around the point of fixation of the stomach, the point where the esophagus passes through the diaphragm, giving rise to a twist.
This occludes both the entrance to and the exit from the stomach so that gas, which is produced in the stomach, cannot escape, giving rise to the distension.
As stated previously, there is considerable doubt concerning the validity of this explanation.
In criticism of this mechanical theory, several objections can be raised. In many cases, there is no evidence that a sudden or vigorous movement of the dog after feeding has occurred. In addition, the contents of the stomach are not such that would facilitate a pendulum-like movement. In the normal, tightly packed, abdominal cavity of the dog, the tonicity of the abdominal muscles, the shortness of the gut, and the normal absence of much gas or fluid, tend to preclude the free mobility visualized for the stomach.
In addition, it has been shown experimentally if the stomach of the dog is distended with air by means of a stomach tube, the stomach eventually twists in either a clockwise or counter-clockwise direction, depending on the position of the spleen at the onset of distension. If the previous theory is correct, there must be some factor which causes the initial distension of the stomach. This factor is not known, but it is probably due to a condition which causes atony or paralysis of the wall of the stomach associated with a large meal and then gas production. Much of the gas found in the stomach could be caused by swallowing air.
The Development of the Disease in the Dog
According to the theory that distension is the primary condition, following distension with gas, the stomach rotates in a clockwise or counter-clockwise direction. The dog is usually severely ill, and can die within one or two hours. The stomach is severely distended, the wall of the stomach is congested, and may even be deprived of blood. The spleen is also twisted and enlarged.
A second situation can occur which is not so serious; the condition is more chronic, and may last several days. Some dogs eventually become severely distended, and may die; however, many recover spontaneously.
What Causes the Death of the Dog?
This condition in the dog has a sudden onset, usually within one to two hours of eating a large meal. The dog is first breathless and, if examined closely, the abdomen is excessively large.
The dog will stand, lie still, or move only with caution. He will generally pass feces and gas so that eventually the entire gut with the exception of the stomach has been emptied. There are often attempts at vomiting although these attempts are rarely successful. In a period varying from one-half to three hours, the stomach becomes grossly distended, and there is severe dyspnea, or difficulty in breathing. The dog may live up to 36 hours but many will die within one to two hours.
There are several explanations for the rapid onset of severe signs and rapid death. It has long been suggested one of the important aspects is the stomach pressing forward on the diaphragm thus compressing the lungs so that the animal has difficulty in breathing. There is experimental and clinical evidence, however, that the rapid development of severe signs can be better explained by the pressure of the enlarged stomach on the vena cava, the large vein which carries blood to the heart from the abdomen and hind legs. As a result of this pressure, there is an inadequate amount of blood returning to the heart, which cannot function effectively as a pump, and therefore, the blood pressure of the animal falls. This produces shock and rapid death. Other factors contribute to a lessor degree to the development of the clinical signs. There is a loss of fluids and electrolytes from the body into the distended gut, and there probably is some pressure by the distended stomach on the lungs, interfering with their function.
It can be seen from this discussion of the cause of death in torsion of the stomach, that the first priority in the treatment of torsion of the stomach must be relief of the distension.
Management of the Dog with Torsion of the Stomach
This is one of the true emergencies in veterinary medicine, and treatment must be instituted immediately if the animal is to survive. If the dog cannot be treated immediately by a veterinarian, the owner may be forced to render first aid to his dog. This is difficult, and there is no uniformly successful method to relieve the distension. In some dogs, a stomach tube can be passed. This can be done by the owner. Unfortunately, it is not possible to do this in dogs with major torsion of the stomach since the entrance into the stomach is obstructed by the twist in the esophagus. Some owners puncture the stomach with a large-bore needle so that the gas will escape. It is probably best to do this on the right side of the dog over the point of greatest distension. Again, unfortunately, this is not always successful. The needle can become obstructed by stomach contents, and there maybe a leakage of fluids and gas into the abdominal cavity with risk of peritonitis. If the animal is severely affected, the owner may have no choice but to attempt one of these methods to relieve the distension.
The dog should be treated by a veterinarian as soon as possible. Unfortunately, there has been insufficient experimental work done by veterinarians on the treatment of torsion of the stomach, and opinions vary on the correct form of therapy.
Many veterinarians advise immediate anesthesia and surgery to relieve the distension and the twist of the stomach. If large volumes of fluids and electrolytes are given by intravenous injection before and during the operation, reasonably good results can be expected.
More satisfactory results have been obtained by a method in which the distension is relieved by a simple surgical procedure. This is later followed by correction of the torsion when the dog is no longer in shock and better able to withstand anesthesia and surgery. This is the method recommended by this author. A small opening is made into the stomach using a local anesthesia. The wall of the stomach is sutured to the skin so that leakage into the abdominal cavity with subsequent peritonitis cannot occur. Fluid and electrolytes are given by intravenous injection; surgery is performed later to close the hole in the stomach and reposition the stomach, if necessary.
Strict control of food and water intake for many days after surgery is needed to avoid a recurrence of the condition.
Prevention
The treatment of torsion of the stomach is unsatisfactory for two reasons. First, the condition develops so quickly that the animal can die in such a short time that many dogs die before treatment can be instituted. Second, it is not possible to save all animals with any of the presently accepted forms of treatment. Using the method in which the distension is relieved and the torsion corrected at a later date, it is expected that 75 to 80 % of dogs should survive. Some dogs are so close to death before treatment that they cannot be saved, and in others, the stomach wall is severely injured by lack of blood supply so that recovery cannot occur.
Therefore, we should direct our attention to prevention of this condition. Unfortunately, there are not generally accepted methods for prevention, and much investigative work is needed.
In some large populations of dogs, such as those in the armed forces, a high incidence of torsion of the stomach has been seen with certain feeding regimens. In many cases, the condition disappears when these dogs are given food ad lib., that is, the dogs have access to a large amount of food so that the dog may eat a small amount of food on many occasions during the day. Obviously, with this management system, the dog has no incentive to eat one large meal at any given time and he does not eat hurriedly.
The most common advice given to owners of large breed dogs is based on experiences such as the one described previously. If there is a high risk, it is best to avoid one large meal per day. The dog should be fed at least twice daily; he should be discouraged from eating rapidly, and he should not be allowed to play actively before and after feeding. The dog should have access to water continuously so there is less chance he will drink a large amount immediately after eating.
It seems there is a high risk of torsion of the stomach if the animal is given one feeding a day, the dog is allowed to drink and to indulge in vigorous exercise after eating. All these factors should be avoided.
Certain drugs that alter the mobility of the gastrointestinal tract have been advocated to prevent gastric torsion. There is no experimental or clinical evidence that any of the presently available drugs is useful. An operation known as pyloroplasty has been advocated by some to increase the size of the exit opening in the stomach. Again, there are no reports in the scientific literature that this procedure should be used.
