Which statement about irritable bowel syndrome is true?
Lactase deficiency is the preferred term
An underlying neuromuscular or hormonal defect is likely
An underlying immunologic defect is likely
The syndrome may be a premalignant state
An underlying neuromuscular or hormonal defect Irritable bowel syndrome, a common cause of alternating diarrhea and constipation, is a functional disorder of motility that probably involves a neuromuscular or hormonal defect. Lactase deficiency is a separate entity that may contribute to irritable bowel syndrome but also may be totally unrelated. There is no evidence of an immunologic defect, and the syndrome is not considered a premalignant state. Incontinence is a symptom of altered anorectal physiology seen with inflammatory diseases of the anal canal and with systemic neuromuscular disorders, such as diabetes or scleroderma; whereas incontinence occasionally may be seen with explosive diarrhea, incontinence is not a common feature of irritable bowel syndrome and should suggest a systemic disorder.