− | An obstruction to gastric emptying due to fluid or gas leads to gastric distention and a rapid increase in intra-gastric pressure. As the stomach dilates, the pylorus shifts in a clockwise fashion from its normal position to a dorsal, cranial and leftward location. Torsion causes impairment of the blood supply- the arterial supply is maintained but venous drainage is blocked. The gastric wall becomes severely congested and infarction of gastric mucosa may occur. The stomach becomes distended with gas and fluid, causing blocked venous return to heart. This compresses the diaphragm and interferes with respiration. | + | An obstruction to gastric emptying due to fluid or gas leads to gastric distention and a rapid increase in intra-gastric pressure. As the stomach dilates, the pylorus shifts in a clockwise fashion from its normal position to a dorsal, cranial and leftward location.The most immediate effect is impairment of the gastric blood supply. The gastric wall becomes severely congested and infarction and ulceration of the gastric mucosa may occur. Venous return to heart is reduced due to mechanical compression of the caudal vena cava by the distended stomach. This compresses the diaphragm and interferes with respiration. |