What causes early dumping syndrome?

Early dumping syndrome is primarily caused by a hyperosmotic load entering the small intestine, which leads to rapid shifts of fluid from the intravascular space into the intestinal lumen. After certain types of gastric surgeries, such as a gastrectomy or gastric bypass, the stomach can empty its contents into the duodenum too quickly. When hyperosmolar food boluses are delivered rapidly to the small intestine, it draws water into the lumen, resulting in symptoms like diarrhea, cramping, and a feeling of fullness. This fluid shift can cause a significant drop in intravascular volume and lead to symptoms of hypotension.

The other options involve mechanisms that do not directly correlate with the rapid onset of symptoms seen in early dumping syndrome. Delayed gastric emptying and food intolerance refer more to conditions that can cause late dumping syndrome or other gastrointestinal motility disorders. Increased gastric acid secretion is a process unrelated to the hyperosmolarity of food reaching the intestine and does not explain the fluid shifts causing early dumping. Impaired intestinal flora leading to gas formation does not relate to the immediate reactions seen in early dumping syndrome, which is centered around fluid dynamics rather than microbial processes.