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The diagnosis of "gastroparesis" suggests that delayed gastric emptying is the underlying cause of symptoms, but this description fails to explain the variable presentation. There are fundamental differences in causes, symptoms, and prognosis among patients with idiopathic gastroparesis. Understanding these differences is necessary in order to provide effective treatment in these patients. We believe our classification for gastroparesis is a useful tool in the management of patients with idiopathic gastroparesis to predict clinical severity, treatment response, and future prognosis.

"Idiopathic gastroparesis" is a poor term to describe this very heterogeneous syndrome. Pathophysiology may not be "idiopathic," but merely unidentifiable with conventional methods suggested for gastroparesis. The diagnosis of "gastroparesis" suggests that delayed gastric emptying is the underlying cause of symptoms, but this description fails to explain the variable presentation. There are fundamental differences in pathophysiology, clinical presentation, severity, and future prognosis among patients with idiopathic gastroparesis. Understanding these differences is necessary in order to provide cost-effective treatment in these patients.

We believe our clinical classification for gastroparesis is a clinical useful tool in the management of patients with idiopathic gastroparesis to predict clinical severity, treatment response, and future prognosis. Patients with vomiting-predominant gastroparesis will be more likely to have an underlying cause, such as viral infection or impaired glucose tolerance with vagal neuropathy. Their symptoms will likely be persistent. Patients with dyspepsia-predominant gastroparesis mimic those with functional dyspepsia and are unlikely to have complications such as weight loss, and dehydration. The necessity of enteric feeding in these patients is also unlikely. Prokinetics may help since delayed gastric emptying may contribute to epigastric pain or postprandial distress. Finding and treating small intestinal bacterial overgrowth as well as suggesting lifestyle and dietary modifications may be helpful. Patients with regurgitation-predominant gastroparesis may benefit most by improving their delayed gastric emptying. Their gastroparesis may cause reflux-like symptoms, especially at night.

Inclusion Criteria:

• Symptoms of gastroparesis (nausea, vomiting, bloating, dyspepsia, early satiety, or effortless regurgitation) >1 month in duration.
• Abnormal 4-hour gastric emptying scan within the past 3 months.
• Initial investigation, based on the AGA Technical Review for gastroparesis, is non-diagnostic for an underlying cause

Exclusion Criteria:

• Presence of endocrine or metabolic diseases: type 1 or type 2 diabetes, hypothyroidism, renal failure, adrenal insufficiency.
• Presence of post-surgical gastroparesis: gastric surgery with vagotomy (with or without gastric resection, esophagectomy; surgery without vagotomy (fundoplication, bariatric surgery, heart-lung transplant).
• Presence of neuromuscular diseases: multiple sclerosis, chronic idiopathic demyelinating polyneuropathy, myotonic dystrophy.
• Presence of connective tissue diseases: systemic sclerosis, mixed connective tissue disorder, polymyositis, dermatomyositis, lupus.
• Presence of autonomic diseases: Central (Parkinson, multiple system atrophy, Lewy body disease, brainstem disease) or Peripheral (idiopathic dysautonomia, amyloidosis, immune-mediated disease, vitamin B12 deficiency, mitochondrial disorder, porphyria, hereditary sensory autonomic neuropathy).
• Presence of paraneoplastic syndrome: small cell lung cancer, multiple myeloma, breast cancer, lymphomas, pancreatic cancer.
• Taking dopamine agonists on a daily basis.
• Presence of known viral infection (Epstein-Barr, cytomegalovirus, herpes simplex, rotavirus), Chagas disease.
• Presence of gastric outlet, small bowel or colon mechanical obstruction.
• Presence of gastric electrical stimulator.
• Non-ambulatory patients: bed-ridden, nursing home resident, etc.
• Presence of active cancer or undergoing cancer treatment.
• Less than 16 years old.
• Pregnancy.
• Unable to provide informed consent.
• Prisoners.

Subjects presenting to the University of Louisville Motility Center with newly diagnosis of idiopathic gastroparesis