Gold Standard Diagnostic Test Underutilized for Gastroparesis

Digestive diseases account for over 100 million visits to outpatient clinic visits annually. Gastroparesis is one of the gastrointestinal conditions seen in this setting, and it is growing in prevalence and often misdiagnosed.

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Gastroparesis is a gastric motility disorder defined by delayed gastric emptying in the absence of mechanical obstruction. According to Alison Schneider, MD, a board-certified gastroenterologist and Director of the GI Motility Lab at Cleveland Clinic Weston Hospital, “About half of patients referred to our center for gastroparesis have been mislabeled.”

Overlapping symptoms

Nausea, vomiting, epigastric pain, and early satiety are characteristic symptoms of gastroparesis. Other symptoms may include bloating, acid reflux, and frequent belching. In addition, patients can develop unintentional weight loss and are at risk for multiple nutrient deficiencies. 

Dr. Schneider states that there is significant overlap with these symptoms and another common condition known as functional dyspepsia. A differential diagnosis also may include cyclic vomiting syndrome, bacterial overgrowth syndrome, cannabinoid hyperemesis syndrome, postprandial regurgitation, pyloric stenosis, malignancy, and medication side effects, among others.

“Too often patients are being diagnosed based on symptoms alone,” says Dr. Schneider. “We believe combining a careful medical history with diagnostic tools, such as a 4-hour gastric emptying study, can help get an accurate diagnosis. It is also important to have tests to rule out organic causes such as esophagogastroduodenoscopy and imaging studies that may include double-contrast gastrointestinal radiologic series.”

Diagnostic gold standard

Gastric emptying scintigraphy (GES) is a nuclear medicine imaging test used to measure the rate of gastric emptying and is considered the “gold standard” to establish the diagnosis of gastroparesis. It is done by tracking a radioactive tracer, such as Technetium-99m (99mTc), as it moves through a patient’s stomach. The short half-life radioactive isotope is added to a standardized meal containing a precise amount of fiber, sugar, protein and fat.

Scans are taken at baseline, 60 minutes, 120 minutes, 180 minutes and 240 minutes to measure food or liquid retention. Patients with greater than 60% of the meal remaining at 2 hours or more than 10% at 4 hours are diagnosed with delayed gastric emptying. A low fat, solid phase meal of egg whites, jam, toast and water is recommended as a standardized meal when doing the study. Research has shown that a 4-hour study has a higher sensitivity and is able to detect gastroparesis 30% more often.

“Our team performs a couple hundred emptying studies a year, and we adhere to the recommended 4-hour duration even though it is more resource intensive,” says Dr. Schneider.

But not all medical centers follow the GES protocol guidelines established in 2008. One study found only 58% of medical institutions responding to a survey performed scintigraphic imaging for the validated 4-hour length of time. Research also has shown that variability in meals given and timing of studies can lead to conflicting results from different institutions.

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“While not the only test used in the diagnosis of gastroparesis, it is the most definitive and easily accessible test,” Dr. Schneider says. “Other tests that are available are gastric emptying breath tests and wireless motility capsule.”

Medical management

“In almost all cases, first line treatments for gastroparesis are dietary modifications followed by prokinetic and antiemetic medications,” says Andrew Ukleja, MD, Director of the Center for Human Nutrition at Cleveland Clinic Weston Hospital. “We recommend a ‘gastroparesis diet’ that consists of low-fat, low-fiber foods and instruct patients to eat small, frequent meals and in some cases to consume largely liquid foods over solids.”

Dr. Ukleja notes it is also important to review all medications a patient with gastroparesis is taking that may contribute to delayed gastric emptying and discontinue or switch them to alternative drugs. Common medications that slow motility include opioids and anticholinergics. This is especially relevant in cases involving the newly popular weight loss medications, semaglutide and tirzepatide, which also slow down gastric emptying.

“The majority of our patients with gastroparesis respond well to medical management, but about 20% to 30% of patients will require additional treatments,” says Dr. Ukleja. “Patients with severe weight loss and uncontrolled symptoms may benefit from other nutritional interventions such as enteral nutrition and, on rare occasions, from parenteral nutrition support.”

Innovative treatments

A variety of pathophysiological abnormalities can lead to gastroparesis, including fundal hypomotility, antral hypomotility, gastric arrhythmia and lack of antro-pyloro-duodenal coordination.

“Gastroparesis can be very difficult to treat when multiple mechanisms are involved,” says Dr. Schneider. “For these patients, we have a number of minimally invasive and surgical treatments that can help relieve symptoms.”

Two endoscopic treatments offered at Weston Hospital address pyloric dysfunction. Short-acting botulinum toxin injections may be administered in cases of suspected pyloric spasm and can provide temporary symptom relief. In confirmed cases, a per oral pyloromyotomy (POP) may be performed.

“During the POP procedure, an endoscope is used to create a submucosal tunnel to reach and cut the muscular sphincter, allowing for easier movement of food between the stomach and small intestine,” explains Dr. Schneider. “Our endoscopy specialists were the first in South Florida to perform this innovative technique.”

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According to a systematic literature review evaluating treatment options for gastroparesis published last year in Surgery for Obesity and Related Diseases, POP was described as a “promising tool in the post-bariatric surgery population with concomitant or post-surgical gastroparesis.”

One of the review’s co-authors, Raul Rosenthal, MD, is Director of The Bariatric & Metabolic Institute at Cleveland Clinic Weston Hospital. He points out that POP also can work in conjunction with another treatment option when multiple components of the gastric emptying process are involved. “In some cases, we’ve found POP combined with gastric electrical stimulation to be effective,” he says.

Gastric electrical stimulation entails surgically implanting a small gastric pacemaker in a subcutaneous pocket in the abdominal wall and two leads into the stomach wall. Short, low voltage electrical pulses are delivered to promote stomach muscle contraction.

“We use a laparoscopic approach to place the device, and the newer generation of stimulators are MRI-safe, which is an advantage over older systems” adds Dr. Rosenthal.

Growing prevalence

The majority of gastroparesis cases are idiopathic (36%), related to diabetes (29%), or post-surgical conditions (13%). Other causes include connective tissue disease, neurologic diseases, myopathies, and medications.

According to a systematic review of epidemiologic data published in 2022, hospitalizations and emergency department visits for gastroparesis have been climbing for the past two decades. One study found a 158% increase in U.S. hospitalizations between 1995 and 2004. “We, too, have more patients showing up in the ER with gastroparesis, and they are often complex cases,” observes Dr. Ukleja.

He also notes post-surgical gastroparesis account for about 5% to 10% of patients with gastroparesis treated at Weston Hospital. “They are among the most challenging to manage and often require feeding tubes and in some cases gastric venting. These individuals benefit the most from our multidisciplinary team approach,” he adds.

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