Postoperative nutritional status

Discussion in 'MRCS Forum' started by Lona., Apr 14, 2008.

  1. Lona.

    Lona. Guest

    A 45-year-old man is involved in a motor vehicle accident and requires laparoscopy. At surgery, the mesentery is torn and the distal small bowel is devitalized. Extensive resection is performed. Postoperative nutritional status is an issue. Which statement regarding absorption by the small intestine is true?

    a- All but the fat in milk is digested and absorbed in humans by the end of the duodenum
    b- Complete absorption of carbohydrates in a normal meal occurs in the ileum
    c- In short gut syndrome, much of the dietary carbohydrate appears in the ileum
    d- Aldosterone markedly decreases sodium transport across the gut mucosa
    e- Enzymes of the brush border of the small intestine can digest and absorb less than 5% of an average protein meal in the absence of the pancreas
  2. Lona.

    Lona. Guest

    Answer: a. (Greenfield, 2/e, pp 812-816) Digestion and absorption of dietary carbohydrate by the duodenum and small intestine are so avid that complete absorption has already occurred by the time ingested food has traversed 200 cm of jejunum. Simple fluids that require minimal digestion, such as milk, are entirely absorbed, save for their fat content, within the duodenum. Even in the short gut syndrome, virtually all dietary carbohydrate is absorbed within the residual jejunum. While pancreatic peptidases are important digestion, redundant digestive enzymes are so widely distributed within the duodenal and jejunal brush border that 95% of a protein meal can be absorbed in the absence of the pancreas. Salt and water flux in the small intestine is influenced by a variety of hormones; aldosterone markedly increases sodium uptake, while prostaglandins stimulate fluid and electrolyte secretion.

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