What are the diagnostic criteria and treatment options for gastroparesis?

Diagnosis and Treatment of Gastroparesis

Gastroparesis is diagnosed based on the presence of characteristic symptoms, delayed gastric emptying on a 4-hour gastric emptying scintigraphy, and the absence of mechanical obstruction. 1, 2

Diagnostic Criteria

Clinical Presentation

• Key symptoms:
  • Nausea and vomiting (predominant symptoms)
  • Postprandial fullness
  • Early satiety
  • Bloating
  • Abdominal pain/discomfort 1

Diagnostic Testing Algorithm

1. Rule out mechanical obstruction:

   • Upper endoscopy is mandatory before proceeding with gastric emptying studies 1, 2
   • Selective imaging when clinically indicated 2

2. Gastric emptying scintigraphy (gold standard):

   • Must be a 4-hour solid-phase study (shorter durations are inaccurate) 1, 2
   • Standard low-fat, egg white meal labeled with 99mTc sulfur colloid 2
   • Interpretation criteria:
     • Normal: <10% retention at 4 hours
     • Mild delay: 10-15% retention at 4 hours
     • Moderate delay: 15-35% retention at 4 hours
     • Severe delay: >35% retention at 4 hours 1, 2

3. Alternative diagnostic methods:

   • 13C-labeled breath tests (when scintigraphy unavailable) 2
   • Wireless motility capsule (specialized centers) 2, 3
   • Antroduodenal manometry (can differentiate neuropathic from myopathic disorders) 1

Special Considerations

• For diabetic patients: Blood glucose should be maintained between 4-10 mmol/L during testing 2
• Acute hyperglycemia can falsely delay gastric emptying 2
• Hypoglycemia can falsely accelerate gastric emptying 2

Treatment Options

Treatment should be guided by symptom severity and degree of gastric emptying delay 1:

1. Dietary Modifications (First-line)

• Small, frequent meals
• Low-fat, low-fiber content
• Replace solids with liquids when symptoms are severe 1, 4

2. Pharmacologic Treatment

• For nausea/vomiting predominant symptoms:

  Prokinetic agents:

  • Metoclopramide: 10 mg orally up to four times daily before meals and at bedtime 5
    • FDA-approved for diabetic gastroparesis
    • Monitor for extrapyramidal side effects, especially in elderly and pediatric patients
    • Consider dose reduction in renal impairment (CrCl <40 mL/min) 5
  • Erythromycin: 125 mg before meals (alternative prokinetic) 4

  Antiemetic agents:

  • Phenothiazines (prochlorperazine, promethazine)
  • 5-HT3 receptor antagonists (ondansetron) for refractory nausea 1, 4
  • NK-1 receptor antagonists for refractory cases 1

• For pain/discomfort predominant symptoms:

  • Treat similar to functional dyspepsia 1
  • Consider low-dose tricyclic antidepressants for symptom modulation 4

3. Refractory Gastroparesis Options

• Pylorus-directed therapies (for pyloric dysfunction):
  • Botulinum toxin injection into the pylorus 1, 4
  • Gastric peroral endoscopic myotomy (G-POEM) for severe cases 1, 3
• Gastric electrical stimulation for medication-refractory cases 1, 6
• Nutritional support:
  • Jejunostomy tube placement for severe, refractory cases 1, 4

Management Based on Severity

1. Mild gastroparesis (10-15% retention):

   • Dietary modifications
   • Antiemetics as needed

2. Moderate gastroparesis (15-35% retention):

   • Dietary modifications
   • Antiemetics plus prokinetics
   • Consider cognitive behavioral therapy/hypnotherapy
   • Consider liquid diet during flares

3. Severe gastroparesis (>35% retention):

   • All above measures
   • Consider enteral feeding via jejunostomy tube
   • Consider gastric electrical stimulation
   • Consider pylorus-directed therapies 1

Common Pitfalls and Caveats

• Symptoms often correlate poorly with the degree of gastric emptying delay 2, 3
• Gastric emptying studies are commonly performed incorrectly; refer to centers that follow proper protocols 1
• Conditions that mimic gastroparesis must be ruled out:
  • Cyclic vomiting syndrome
  • Cannabinoid hyperemesis syndrome
  • Rumination syndrome
  • Functional dyspepsia (significant overlap with gastroparesis) 1
• In diabetic patients, poor glycemic control can worsen symptoms and delay gastric emptying 1, 2
• Metoclopramide carries a black box warning for tardive dyskinesia with long-term use; limit treatment to 12 weeks when possible 5