What are the diagnostic approaches and treatment options for gastroparesis?

Diagnostic Approaches and Treatment Options for Gastroparesis

Gastroparesis should be diagnosed using gastric emptying scintigraphy performed for at least 2-4 hours after ingestion of a standardized radiolabeled meal, with treatment tailored to the predominant symptom and severity of delayed emptying. 1, 2

Diagnostic Approach

Definition and Clinical Presentation

• Gastroparesis is defined as delayed gastric emptying in the absence of mechanical obstruction, characterized by symptoms including nausea, vomiting, early satiety, postprandial fullness, bloating, and abdominal pain 2
• The most common etiologies are diabetic (20-40% of diabetic patients), idiopathic (approximately 50% of cases), and postsurgical 2, 3

Diagnostic Testing

• Gastric emptying scintigraphy is the gold standard for diagnosis and should be performed for at least 2 hours, with 4-hour testing providing higher diagnostic yield and accuracy 1, 2

• The radioisotope must be cooked into the solid portion of the meal (typically a standardized low-fat egg white meal labeled with 99mTc sulfur colloid) 1

• Important test preparation considerations:

  • Medications that influence gastric emptying should be withdrawn 48-72 hours prior to testing 1
  • Smoking should be avoided on the test day 1
  • Blood glucose should be monitored and maintained within normal range during testing, as hyperglycemia can slow gastric emptying 1

• Alternative diagnostic methods include:

  • Breath testing using non-radioactive substances, which correlates well with scintigraphy 1
  • Antroduodenal manometry to differentiate between neuropathic or myopathic motility disorders 1

Diagnostic Algorithm

1. Rule out mechanical obstruction with upper endoscopy 1, 2
2. Perform gastric emptying scintigraphy with proper methodology 2, 1
3. Classify gastroparesis severity based on symptoms and degree of emptying delay 2
4. Identify the predominant symptom to guide treatment approach 2

Treatment Options

Dietary Modifications

• Smaller, more frequent meals with lower fat and fiber content 1, 3
• Maintain adequate hydration (≥1.5 L fluids/day) 1
• Evaluate eating behaviors (eating too quickly, insufficient chewing, overeating) 1

Pharmacologic Treatment

For Nausea and Vomiting

• Multiple treatment options should be considered for nausea and vomiting 2
• Antiemetic agents such as phenothiazines, 5-HT3 antagonists, and NK-1 receptor antagonists may be used 3, 4

For Gastric Emptying Delay

• Metoclopramide is FDA-approved for diabetic gastroparesis:
  • Standard dosing is 10 mg orally up to four times daily before meals and at bedtime 5
  • For severe symptoms, initial therapy may begin with metoclopramide injection (IM or IV) 5
  • Use with caution in elderly patients and those with renal impairment (reduce dose by half if creatinine clearance <40 mL/min) 5
  • Monitor for extrapyramidal side effects, especially in pediatric and elderly populations 5
• Other prokinetic agents include prucalopride and relamorelin 4

For Abdominal Pain

• Neuromodulators should be considered for gastroparesis-associated abdominal pain 2
• Opioids should be avoided as they can worsen gastric emptying 2, 5
• Fundic relaxants (acotiamide, buspirone) may help with symptoms related to impaired gastric accommodation 4

Interventional Approaches for Refractory Cases

• Gastric electrical stimulation (GES) can be considered for patients with refractory/intractable nausea and vomiting who have failed standard therapy and are not on opioids 2
• Gastric per-oral endoscopic myotomy (G-POEM) may be considered for select patients with severe delay in gastric emptying, using a team approach involving motility specialists and advanced endoscopists at centers of excellence 2, 4

Common Pitfalls to Avoid

• Relying solely on symptoms for diagnosis is inadequate as symptoms correlate poorly with the degree of gastric emptying delay 1
• Failure to control blood glucose during testing can lead to false positive results 1
• Not accounting for medications that can affect gastric emptying (prokinetics, opioids, anticholinergics) can lead to inaccurate results 1, 5
• Using opioids for pain management in gastroparesis patients can worsen gastric emptying and symptoms 2, 5