by Dr. Bill Ehlers, D.V.M.
Gastric torsion and gastric dilatation volvulus (GVD) are the medical terms synonymous with bloat. This occurs when the stomach dilates and rotates on itself, and it occurs most commonly in large and giant deep chested breeds of dogs of any age.
The process is thought to begin with dilation of the stomach. The enlargement is thought to be associated with an outflow obstruction of the stomach and once the stomach dilates normal means of removing air from it are removed. The stomach enlarges as gas and fluid accumulate. The gas probably comes from swallowed air, although bacteria presence may contribute.
is theorized that rotation occurs after dilation, and the dilated stomach continues to rotate or twist on itself until food, fluid and gases are prevented from flowing into the intestines. This is termed volvulus.
The causes for this process however are not well understood. As mentioned, the dilation is thought to be associated with delayed emptying of the stomach due to obstruction or stomach disease but constant overeating with the resulting stretching of the stomach and increased activity after eating and drinking have all been theories as to why the condition occurs.
Early recognition of the signs of bloat is very important to the successful treatment, and the signs are rapid in onset. They include increased salivation, unproductive vomiting and an increase in size to the front portion of the abdomen. As the stomach dilates, circulation of blood through the stomach can stop which causes damage to the stomach. There is also a decrease in the return of blood to the heart. The output of blood from the heart then goes down and this decreases oxygen to the tissue of the rest of the body resulting in shock. Signs of shock include pale mucus membranes increased heart rate and weak pulses. This is an emergency situation.
The treatment is based on stabilizing the above effects first. This includes the use of intravenous fluids, antibiotics, correction of heart arrhythmias and decompression of the stomach by a stomach tube through the mouth or by a needle through the skin and into the stomach.
When stabilization has occurred, surgery is performed to fully decompress and derotate the stomach. The stomach is then sutured in a way to prevent the condition from recurring.
Some preventative measures which can be performed include feeding smaller more frequent meals rather than one large meal per day, separating dogs in multiple dog households during feeding to avoid stress and restricting exercise before and after meals.
For additional information on how to identify bloat, see the article:
ASPCA Dog Care - Bloat.