Gastroparesis can be tricky to diagnose and treat, in part because its symptoms can be difficult to distinguish from functional dyspepsia. A new clinical practice update from the American Gastroenterological Association aims to help physicians treat medically refractory gastroparesis with practical advice stemming from expert opinion and a literature review.
Although gastroparesis can be caused by known factors such as diabetes and medications, the largest group is idiopathic. The authors define medically refractory gastroparesis as symptoms that are not due to medication use, that continue despite dietary changes and first-line treatment with metoclopramide.
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Although the authors outline several best practice advice statements on symptom identification and management, they acknowledge that much uncertainty still exists. “Our knowledge gap remains vast, and areas for future research include study of pathophysiology and etiology, as well as identification of clinical and investigation-based predictors of response to each management approach,” the authors wrote. Their report is in Clinical Gastroenterology and Hepatology.
They also call for research to identify gastroparesis phenotypes that are most likely to respond to individual management approaches.
Common gastroparesis symptoms include nausea, vomiting, early satiety, bloating, postprandial fullness, abdominal pain, and weight loss. Many of these overlap with functional dyspepsia (FD). In fact, one study found that 42% of gastroparesis could be reclassified as having functional dyspepsia, and 37% of FD patients as having gastroparesis.
About 5 million adults in the United States, and 7.2% of the world population, report gastroparesis-like symptoms. The similarities between the two groups poses a significant diagnostic challenge. However, a careful history, physical exam, and appropriate diagnostic tests should allow the physician to rule out other conditions that may mimic gastroparesis. Repeating scintigraphy may change diagnosis from gastroparesis to FD or vice versa, but the authors note that this technique is often performed incorrectly and so should be conducted at centers that closely follow guidelines. They suggest a 4 hour meal-based test of gastric emptying over the wireless motility capsule because it provides a better physiological assessment.
They also suggest that treatment should focus on the most bothersome symptom, along with reducing the potential for complications such as esophagitis, malnutrition, and weight loss, as well as improving quality of life.
There are medications available for nausea and vomiting, although most have not been studied in large randomized controlled trials. These agents include domperidone, 5-hydroxytryptamine3 receptor antagonists, neurokinin receptor antagonists, and phenothiazine antipsychotics.
There are also medications available to increase the rate of gastric emptying. Erythromycin can be used intravenously or orally ahead of meals, while the 5-HT4 receptor agonist velusetrag improved gastric emptying in healthy volunteers with no sign of cardiac side effects. The commonly available 5-HT4 agonist prucalopride has also shown promise in improving gastric emptying.
For visceral pain, the authors suggest not using opioids because they may slow gastric emptying and increase pain perception. It is believed that neuromodulators such as tricyclic antidepressants (TCAs) and serotonin norepinephrine reuptake inhibitors (SNRIs) may reduce perception of pain, but there is limited high-quality evidence available for these therapies. The authors suggest that higher potency tertiary tricyclic amines such as amitriptyline or imipramine may be effective, particularly in diabetic gastroparesis since they provide relief in FD.
Nonpharmaceutical options include gastric electrical stimulation (GES), which improves refractory nausea and vomiting in some patients with gastroparesis, but does not accelerate gastric emptying. It may also improve glycemic control, nutritional status, and quality of life. The treatment may be well suited to opioid-free patients with refractory or intractable nausea and vomiting whose predominant symptom is not abdominal pain.
Other therapies focus on the pylorus and its role in gastric emptying, which can be impaired as a result of abnormalities of pyloric tone and pressure. Functional lumen imaging probe (FLIP) can be used to probe pyloric tone and pressure, but it is expensive, invasive, and not widely available.
Outside of clinical trial settings, the authors advise against the use of intrapyloric botulinum toxic injection and transpyloric stent placement. Per oral endoscopic myotomy (POEM) has shown some efficacy at improving symptoms and reducing gastric emptying times, but it has not been studied in sham-controlled trials. The authors call the technique intriguing, but say it should not be considered a first-line therapy, and should be performed only at tertiary centers with expert motility specialists and endoscopists.
In extreme cases, enteral nutrition may be necessary, and a transjejunal tube or combined gastrojejunostomy tube should be emplaced beyond the pylorus. In a retrospective case series, patients experienced weight recovery with acceptable morbidity and mortality, and the implant was removed at an average of 20 months.
The authors have consulted or been on scientific advisory boards for Salix, Ironwood, Allergan, Arena, Allakos, Medtronic, Diversatek, Takeda, Quintiles, and IsoThrive.
This article was updated Feb. 17, 2022.
