Gastroparesis is a disorder in which the stomach muscles function improperly, causing food and liquid to pass too slowly into the small intestine. It is also called delayed gastric emptying or stomach paralysis, and often occurs in patients with type 1 or type 2 diabetes. Diabetes is a disorder in the body’s ability to effectively produce or use the hormone insulin, which regulates blood sugar (glucose).

Gastropathy is a term used for milder cases that may be temporary and reversible. Gastroparesis is more severe and usually chronic. Gastropathy is more common than gastroparesis.

The stomach is a saclike organ located between the esophagus and the small intestine. It has three layers of muscles whose function is to crush food and mix it with enzymes and acids. After food enters the stomach, it is pulverized and propelled to the pyloric sphincter (the muscle between the stomach and the small intestine) by muscular contractions (peristalsis). The pyloric sphincter then pushes the food to the duodenum (the first part of the small intestine connected to the stomach).

The muscular contractions of the stomach are controlled by the vagus nerve (a nerve that originates in the brainstem and plays a role in both sensory and motor functions). The vagus nerve sends signals to the smooth muscles of the stomach, causing them to contract.

The vagus nerve can become damaged when blood sugar levels are elevated for a prolonged period of time, which is common in patients with diabetes. The vagus nerve can also become damaged during surgery to the esophagus, stomach or duodenum.

Under normal circumstances, about one-eighth of an ounce of food is released from the stomach to the small intestine at a time. It typically takes approximately three to four hours for contents to pass entirely through the stomach, although the time varies according to the types of food ingested (foods high in fat and/or fiber require more time to pass through the stomach). However, in patients with gastroparesis, the time required for food to pass through the stomach is much longer.

When food and liquid remain in the stomach for too long, it can cause complications including:

• Weight loss and malnutrition. Patients with gastroparesis have less food enter the small intestine because of vomiting and they eat less because of symptoms.  This leads to weight loss and malnutrition.
  
  
• Bezoars. Collections of solid masses of partially-digested or undigested materials, such as fiber or vegetable matter (phytobezoars). Bezoars can cause complications if they block food from entering the small intestine (intestinal obstruction).
  
  
• Diabetes complications. Disruptions in the body’s ability to absorb food may result in wide fluctuations of blood sugar levels. When food is released from the stomach and is absorbed in the small intestine, blood sugar levels rise. When blood sugar levels are erratic, they are more difficult for diabetes patients to control.

Gastroparesis can also cause overgrowth of bacteria in the stomach and impair the absorption of oral medications.