How does gastroparesis start or the causes are and how to prevent gastroparesis?

Several factors: The exact cause of gastroparesis is not known but is thought to be secondary to vagus nerve being affected. Diabetes especially if uncontrolled or long standing and after surgery especially abdominal surgery can lead to gastroparesis. There are several medications that can increase the risk for gastroparesis like opioid pain medications, allergy medications, antidepressants and some bp meds.