What is the recommended management and diagnostic approach for a patient with suspected gastroparesis or delayed gastric emptying?

Management and Diagnostic Approach for Suspected Gastroparesis

The recommended approach for patients with suspected gastroparesis requires a 4-hour gastric emptying scintigraphy study as the gold standard diagnostic test, followed by symptom-based treatment that includes dietary modifications, prokinetics for nausea/vomiting, and neuromodulators for pain, while avoiding opioids. 1, 2

Diagnostic Approach

Initial Evaluation

• Review cardinal symptoms: nausea, vomiting, early satiety, postprandial fullness, bloating, and abdominal pain 2
• Rule out mimicking conditions:
  • Cyclic vomiting syndrome
  • Cannabinoid hyperemesis syndrome
  • Rumination syndrome
  • Functional dyspepsia 1, 2
• Identify risk factors:
  • Diabetes (especially long-standing type 1)
  • Prior gastric surgery
  • Medications (opioids, GLP-1 agonists)
  • Post-viral illness 2

Required Testing

1. Upper endoscopy - mandatory before gastric emptying studies to rule out mechanical obstruction and structural causes 2

2. Gastric emptying scintigraphy (gold standard) 1, 2

   • Protocol: 4-hour study with radiolabeled solid meal

   • Imaging at 0,1,2, and 4 hours

   • Interpretation criteria:

     Severity	Retention at 4 hours
     Normal	<10%
     Mild	10-15%
     Moderate	15-35%
     Severe	>35%

   • Important considerations:

     • 4-hour duration is essential (2-hour studies miss up to 36% of cases) 3
     • Control glucose levels during testing in diabetic patients 2
     • Discontinue medications affecting gastric emptying before testing (prokinetics, opioids, anticholinergics, GLP-1 agonists) 2

3. Alternative diagnostic tests (when scintigraphy unavailable):

   • 13C-labeled breath tests
   • Wireless motility capsule 2
   • Antroduodenal manometry (helps diagnose small bowel obstruction or rumination syndrome) 2

Treatment Algorithm

Step 1: Classify Severity

• Mild (10-15% retention at 4 hours)
• Moderate (15-35% retention at 4 hours)
• Severe (>35% retention at 4 hours) 1, 2

Step 2: Identify Predominant Symptom 1

• Nausea/vomiting predominant
• Pain/discomfort predominant
• Early satiety/fullness predominant

Step 3: Treatment Based on Severity and Symptoms

For All Patients:

• Dietary modifications 1, 2

  • Small, frequent meals
  • Low-fat, low-fiber content
  • Replace solids with liquids when symptoms are severe

• Optimize glycemic control in diabetic patients 2

• Discontinue medications that delay gastric emptying (especially opioids) 4

  • Opioid use correlates with increased severity of gastric emptying delay and 50% of opioid users have severely delayed gastric emptying 4

For Nausea/Vomiting Predominant:

• Prokinetic agents 1, 2, 5

  • Metoclopramide 10 mg orally 30 minutes before meals and at bedtime
    • For severe symptoms, may start with IV/IM administration before transitioning to oral 5
    • Reduce dose by 50% in patients with creatinine clearance <40 mL/min 5
  • Monitor for and discuss potential side effects (extrapyramidal symptoms)

• Antiemetic agents if needed 1, 2

  • Phenothiazines
  • 5-HT3 receptor antagonists (ondansetron)

For Pain/Discomfort Predominant:

• Neuromodulators 1
  • Low-dose tricyclic antidepressants
  • SNRIs
  • Avoid opioids - they worsen gastric emptying 1, 4

For Refractory Cases (Severe Gastroparesis):

• Pylorus-directed therapies 1, 2

  • Botulinum toxin injection into the pylorus
  • Gastric peroral endoscopic myotomy (G-POEM)

• Gastric electrical stimulation for medication-refractory nausea/vomiting 1, 2

• Nutritional support 1, 2

  • Jejunostomy tube placement for severe, refractory cases

Monitoring and Follow-up

• Patients with severe delay in gastric emptying require closer monitoring as they have increased risk of hospitalizations and emergency department visits 4
• Consider repeat gastric emptying studies to assess treatment response in refractory cases

Important Caveats

• Symptoms do not correlate well with the degree of gastric emptying delay 1, 3
• Liquid gastric emptying may be delayed in some patients with normal solid emptying, particularly in non-diabetic patients 6
• Symptoms correlate better with gastric retention at later time points (3-4 hours) than earlier time points 3
• Treatment should focus on symptom control and maintaining adequate nutrition and hydration 7