Intestinal failure

Abstract

The small bowel is a marvellous organ. First, it absorbs nutrients on behalf of all the other organs of the body. This function is not entirely ‘altruistic’: enteric (small-bowel) epithelium is itself nourished by luminal nutrients, which explains its disproportionately severe atrophy in starvation or total parenteral nutrition. Second, it has an enormous functional reserve. In the era of jejunoileal bypass for morbid obesity, most patients with 85–90% of the small bowel taken out of circuit could still maintain a body weight above normal. Third, the fact that diarrhoea after a major enterectomy diminishes with time indicates the adaptive power of the remnant small intestine. The lining of the jejunum and ileum is normally shed every few days as cells migrate from crypt base to villus tip, yet the process can be further accelerated to compensate for loss of tissue mass.