Gastric Emptying Study (cont.)
How is a gastric emptying study done?
For a gastric emptying study, a patient eats a meal in
which a solid component of the meal (for example, scrambled egg), a liquid
component of the meal (for example, water), or both, are mixed with a small amount of radioactive
material. A scanner (acting like a Geiger counter) is placed over the patient's
stomach to monitor the amount of radioactivity in the stomach for several hours
after the test meal is eaten. As the radioactively-labelled food empties from
the stomach, the amount of radioactivity in the stomach decreases. The rate at
which the radioactivity leaves the stomach reflects the rate at which food is
emptying from the stomach
Some medications such as narcotic pain
relievers and anticholinergic
medications can cause delay emptying of the stomach, while other medications
such as metoclopramide (Reglan) and erythromycin can cause
rapid emptying of the stomach. Medications that slow emptying of the stomach can
give a falsely abnormal test result, while medications that speed up emptying of
the stomach can give a falsely normal result. Therefore, medications that affect
emptying of
the stomach should be withheld for 48-72 hours before performing emptying
studies. Abnormally high blood glucose (sugar)
levels also can slow emptying of the stomach. Therefore, it is important to
control blood glucose levels to near
normal levels before performing emptying studies in patients with diabetes who
are prone to develop high blood glucose levels.
When is a gastric emptying study used?
A gastric emptying study often is used when there is a
suspicion that there is abnormally delayed emptying of food from the stomach,
medically called delayed gastric emptying. Delayed gastric emptying most
commonly gives rise to abdominal discomfort after meals, nausea and vomiting. The two most common
causes of delayed gastric emptying are gastric outlet obstruction and gastroparesis.
Gastric outlet
obstruction refers to
a condition in which the narrow channel leading from the stomach into the small
intestine through which food passes
(called the pylorus) is physically blocked, and, as a result food enters the
first part of the small intestine (called the duodenum) slowly or not
at all. The most common causes of gastric outlet obstruction are scarring or
inflammation of the pylorus from peptic ulcers, cancers of the stomach, or,
occasionally, cancers near the pylorus, for example, of the pancreas or
duodenum. A diagnosis of gastric outlet obstrution is made by tests such as
esophagogastroduodenoscopy (EGD), abdominal computerized tomography (CT scan),
and upper GI series.
Once gastric outlet obstruction has been excluded by
appropriate testing as the cause of delayed gastric emptying, physicians then
may perform a gastric emptying study to diagnose gastroparesis. Gastroparesis is
a condition in which there is delayed gastric emptying, but the delay is not due
to obstruction. Rather, it is due to abnormal function of the muscles of the
stomach. Normal function of the stomach's muscles is necessary in order to
propel food from the stomach and into the small intestine. If the muscles or the
nerves that control the muscles are not working normally, food remains in the
stomach. Gastroparesis is commonly caused by diseases and medications. The most
common cause of gastroparesis is diabetes mellitus.
A gastric emptying study also may be used when there is
a suspicion that there is abnormally rapid gastric emptying. Rapid gastric
emptying can cause diarrhea and episodes of weakness or light-headedness
following meals (referred to as the "dumping" syndrome). Common causes of rapid
gastric emptying include surgery of the stomach and diabetes mellitus.
Next: How are the results of a gastric emptying study evaluated? »
- metoclopramide, Reglan, Octamide, Maxolon - Read about metoclopramide (Reglan, Octamide, Maxolon), a drug used to treat heartburn, diabetic gastroparesis, and esophagitis due to gastroesophageal reflux. Side effects, drug interactions, and dosage information is also included.
- CT Scan (Computerized Axial Tomography) - CT Scan (Computerized Axial Tomography, CAT scan) is a procedure that assists in diagnosing tumors, fractures, bony structures, and infections in the organs and tissues of the body.
- Abdominal Pain - Learn about abdominal pain (pain in the stomach / abdomen) including causes, symptoms, how abdominal pain is diagnosed, and how abdominal pain is treated.
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