A boy comes with complains of vomiting, bloated abdomen and abdominal pain. He has history of attending ice-cream eating competition last night. He also has past history of similar episodes following ingestion of milk and milk products. The likely cause -

Ans. is 'b' i.e., Lactase deficiency History of ice cream ingestion and subsequent symptoms of vomiting, bloated abdomen, are characteristic findings of lactase deficiency. Lactase deficiency ? o Lactase is a disaccharidase present on intestinal epithelium (brush border)*. It is used to digest lactose (disaccharide). Symptoms arise after ingestion offood containing lactose (e.g. milk). Symptom - Diarrhoea, vomiting, bloated abdomen. o Diagnosis Presence of more than '/2 percent of reducing substrate in fresh stool. Acidic stools Abnormal oral sugar tolerance test* (blood glucose rise of less than 20mg/d1 above fasting level with a disaccharide load of 2g/kg) Breath H, excretion of more than 11 ppm*. Enzyme assay on mucosal biopsies showing low levels of disaccharidases. o Treatment - low lactose diet.