Small bowel, mid-, and hindgut dysmotility involvement has often been associated with pathologies of intragastric motility. Not only GI but genitourinary dysfunction may be associated with fore- and mid-gut dysfunction in GpS. Equally well described are abnormalities of the autonomic and sensory nervous system, which have recently been better quantified. Serologic measures, such as channelopathies and other antibody mediated abnormalities, have been recently noted.
Suspected for many years, immune dysregulation has now been documented in patients with GpS. Further investigation, including genetic dysregulation of immune measures, is ongoing. Other mechanisms include systemic and local inflammation, hormonal abnormalities, macro- and micronutrient deficiencies, dysregulation in GI microbiome, and physical frailty. The above factors may play a role in the pathophysiology of GpS, and it is likely that many of these are involved with a given patient presenting for care.9
Diagnosis of GpS
Diagnosis of GpS is often delayed and can be challenging; various tools have been developed, but not all are used. A diagnostic approach for patients with symptoms of Gp is listed below, and Figure 2 details a diagnostic approach and treatment options for symptomatic patients.
Fig. 2: Diagnostic and treatment approach for patients with gastroparesis symptoms explained.
Symptom Assessment: Initially Gp symptoms can be assessed using Food and Drug Administration–approved patient-reported outcomes, including frequency and severity of nausea, vomiting, anorexia/early satiety, bloating/distention, and abdominal pain on a 0-4, 0-5 or 0-10 scale. The Gastrointestinal Cardinal Symptom Index or visual analog scales can also be used. It is also important to evaluate midgut and hindgut symptoms.9-11
Mechanical obstruction assessment: Mechanical obstruction can be ruled out using upper endoscopy or barium studies.
Physiologic testing: The most common is radionuclide gastric emptying testing (GET). Compliance with guidelines, standardization, and consistency of GETs is vital to help with an accurate diagnosis. Currently, two consensus recommendations for the standardized performance of GETs exist.12,13 Breath testing is FDA approved in the United States and can be used as an alternative. Wireless motility capsule testing can be complimentary.
Gastric dysrhythmias assessment: Assessment of gastric dysrhythmias can be performed in outpatient settings using cutaneous electrogastrogram, currently available in many referral centers. Most patients with GpS have an underlying gastric electrical abnormality.14,15
Sphincter dysfunction assessment: Both proximal and distal sphincter abnormalities have been described for many years and are of particular interest recently. Use of the functional luminal imaging probe (FLIP) shows patients with GpS may have decreased sphincter distensibility when examining the comparisons of the cross-sectional area relative to pressure Using this information, sphincter therapies can be offered.16-18
Other testing: Neurologic and autonomic testing, along with psychosocial, genetic and frailty assessments, are helpful to explore.19 Nutritional evaluation can be done using standardized scales, such as subjective global assessment and serologic testing for micronutrient deficiency or electrical impedance.20
