Post-infectious lactose intolerance and irritable bowel syndrome

Background

• Definition is IBS meeting Rome criteria that immediately follows a gastrointestinal illness characterized by at least two of fever, vomiting, diarrhea, or positive stool culture

Clinical Manifestations

• Diarrheal illness followed by persistent diarrhea despite appropriate treatment
• Can occur following dysentery or C. difficile infection

Management

• Week one: lactose-free diet
  • Avoid all lactose-containing foods, including milk and milk products like cheese, cream, yoghurt, and ice creams
  • If symptoms significantly improve, continue the lactose-free diet
  • If symptoms do not significantly improve, proceed to week two
• Week two: high-fibre diet
  • Start psyllium fibre (such as Metamucil) 1-2 tablespoons in a glass of juice or water daily, followed by another glass of juice or water
    • May cause bloating and gas (which improve), or rare allergy
    • Use sugar-free psyllium fibre
  • Start PEG 3350 1-2 tablespoons once daily (can be mixed with psyllium fibre)
    • May cause bloating and gas
  • Consider avoiding alcohol, caffeine, spicy food, stress, and gas-producing foods (broccoli, cabbage, Brussels sprouts, beans, etc.) which can trigger or worsen irritable bowel syndrome

Prognosis

• Lasts a median of 2 years

Further Reading

• Postinfectious irritable bowel syndrome. Gastroenterology. 2009;136(6):1979-88. doi: 10.1053/j.gastro.2009.02.074.