What is the treatment for Monosodium Glutamate (MSG)-induced enterocolitis?

Treatment for MSG-Induced Enterocolitis

The treatment for MSG-induced enterocolitis should follow the same protocol as Food Protein-Induced Enterocolitis Syndrome (FPIES), with complete elimination of MSG from the diet as the cornerstone of management, along with appropriate treatment of acute reactions based on severity. 1, 2

Acute Reaction Management

Treatment depends on reaction severity:

Mild Reactions

• 1-2 episodes of emesis with no or mild lethargy
• Attempt oral rehydration at home (clear fluids)
• Monitor for 4-6 hours from symptom onset

Moderate to Severe Reactions

• 3 episodes of emesis with moderate-to-severe lethargy

• Emergency management required:
  • Establish IV access with rapid normal saline bolus (20 mL/kg)
  • Administer ondansetron 0.15 mg/kg IV or IM (maximum 16 mg) if ≥6 months old
  • Consider IV methylprednisolone 1 mg/kg (maximum 60-80 mg)
  • Monitor and correct acid-base and electrolyte abnormalities
  • Monitor vital signs
  • Discharge after 4-6 hours when patient returns to baseline and tolerates oral fluids

Caution: Ondansetron should be used carefully in patients with heart disease due to potential QT interval prolongation 2

Long-term Management

1. Complete elimination of MSG from diet

   • Avoid all foods containing MSG
   • Read food labels carefully (MSG may be listed as "flavor enhancer," "hydrolyzed vegetable protein," or "E621")
   • Avoid processed foods, restaurant foods (particularly Asian cuisine) which commonly contain MSG 3

2. Nutritional consultation

   • Ensure adequate nutrition despite dietary restrictions
   • Develop strategies for avoiding hidden sources of MSG

3. Follow-up and monitoring

   • Regular assessment for resolution of symptoms
   • Consider oral food challenge under medical supervision to confirm diagnosis if history is unclear

Diagnostic Considerations

MSG-induced enterocolitis may be misdiagnosed as:

• Infectious gastroenteritis
• Sepsis
• Food aversion
• Lactose intolerance
• Gastrointestinal reflux disease

Diagnosis is favored if there is:

• Rapid resolution of symptoms within hours
• Absence of fever
• Lack of significant rise in C-reactive protein
• Clear temporal relationship between MSG ingestion and symptom onset (1-4 hours after ingestion)

Special Considerations

• While MSG has been reported to cause Type I allergic reactions in rare cases 3, enterocolitis represents a non-IgE-mediated food hypersensitivity reaction
• MSG consumption has been associated with other metabolic disorders including obesity, diabetes, and hypertension 4, but these are distinct from the acute enterocolitis reaction
• For patients with severe reactions, an emergency action plan should be provided, including when to seek emergency care

When to Seek Emergency Care

Instruct patients to call 911 or go to the emergency department immediately if:

• The patient has a history of severe reactions and has definitely ingested MSG
• The patient experiences >3 episodes of vomiting
• Moderate-to-severe lethargy develops
• Signs of dehydration are present
• Hypotension or respiratory distress occurs

By following these guidelines, most patients with MSG-induced enterocolitis can be effectively managed with good outcomes.