Understanding GP

What Happens in Gastroparesis?

Intro / Digestion / Who gets GP / What happens / Symptoms / Dx / Mild forms / Tx
 

Theories related to delayed gastric emptying:

Gastroparesis is delayed gastric emptying (emptying of the stomach). It is a disorder of gastrointestinal function, that is, the stomach and intestines, or as we have colloquially called it here, the tummy and gut. Examination shows no structural abnormalities of the gut, no inflammation, no blood, no other obvious signs of disease. Gastroparesis is a problem of motility.

The diagnostic test for gastroparesis is a gastric emptying test (GET). If you follow the "Tummy Tour", it is felt that the stomach’s antrum, pylorus, and the duodenum each may play a role in the delayed emptying of the stomach. Each individual may have various degrees of dysfunction in these GI regions culminating in delayed stomach emptying.

ANTRUM
Motility studies have demonstrated that ANTRAL HYPOMOTILITY (weak contractions in the antrum part of the stomach) is a consistent finding in gastroparesis (more on this in the “Diagnosis” section).
 

PYLORUS
The pylorus sphincter is capable of generating both continual and intermittent contractions. These contractions may be coordinated with, or take place independent of, contractions of the stomach antrum as well as of the duodenum! Localized pyloric contractions (spasms) can cause sustained closure of the pylorus that can interrupt gastric emptying¹.

DUODENUM
Mechanical events in the duodenum may also play a role in inhibiting gastric emptying.

• High-pressure activity of the duodenum may increase resistance and delay gastric emptying.

• Uncoordinated contractions of the duodenum may also cause inadequate movement of digested food from the start of the duodenum to a more distant part of the small intestine, leading to a delay in gastric emptying.

CO-ORDINATING THE ANTRUM, PYLORUS AND DUODENUM

If there are no mechanical obstructions, delayed emptying may result from a variety of abnormalities:

• Decreased tone in the stomach fundus (top portion of the stomach)

• Diminished force or diminished frequency of stomach contractions in the antrum (lower section of the stomach).

• Abnormally increased contractions of the pylorus (spasms)

• Lack of co-ordination of contractions between the antrum, pylorus and duodenum

As you can see, a pathological (disease-related) delay in stomach emptying is a very complex issue, with one or more factors interfering with the stomach's ability to empty. Medical science is just beginning to unravel these mysteries. One finding that seems to predominate in all research, is a finding of antral hypomotility (described under “Antrum” above). Other individuals may also have problems with the motility of their pylorus and/or duodenum. With so many possible contributing factors to delayed stomach emptying, it is important to find a good gastroenterologist who is well acquainted with you and the particular factors that play a role in your illness. The number of diverse factors also helps to explain why individuals vary in response to medications, and why one treatment approach does not work for all. The complexity of this disorder makes it important to have a good doctor-patient relationship, and to find a plan of treatment that works for you. Remember that doctors don't have all the answers, nor do they have all the tools to help. One disturbing fact illustrating the lack of diagnostic tools is that some individuals can have normal gastric emptying studies, yet be completely debilitated with nausea!

1. Parkman H P, Harris A D, Krevsky B, Urbain J L, Maurer A H, Fisher R S: Gastroduodenal Motility and Dysmotility an Update on Techniques Available for Evaluation. The American Journal of Gastroenterology 1995;90:869-89.