Rx Note

Introduction Lactose intolerance is usually due to a deficiency of the digestive enzyme in the small bowel mucosa, resulting in lactose malabsorption. Symptoms Incompletely absorbed lactose is subsequently fermented by bacteria in the large bowel causing Abdominal pain Bloating Flatulence Watery diarrhoea Occasionally, nausea and vomiting Symptoms associated with lactose ingestion are not always due to lactose deficiency; they may be due to rapid transit of lactose through the small bowel. Lactase deficiency can be primary with delayed onset (i.e. adult lactase deficiency), secondary or congenital. Delayed-onset primary lactase deficiency may begin from 7 years of age. Differential Diagnosis The diagnosis is suspected based on dietary history. The differential diagnosis includes physiologically incomplete absorption of simple carbohydrates (e.g., sorbitol, mannitol, xylitol, fructose, FODMAP) and therapeutic inhibitors of carbohydrate absorption (e.g., acarbose), which can cause sympt...