pancreatectomy for chronic pancreatitis

Discussion in 'MRCS Forum' started by Fraink., Apr 16, 2008.

  1. Fraink.

    Fraink. Guest

    After a total pancreatectomy for chronic pancreatitis, a nutritional plan is being devised. Fat intake is of particular concern. Which statement regarding fat absorption is true?

    a- Half of neutral fat can be absorbed in the complete absence of bile and pancreatic lipase
    b- Fifty percent of the total bile salt pool is lost in the stool and replaced daily by synthesis in the liver
    c- Glycerol, short-chain fatty acids, and medium-chain triglycerides exit the mucosal cell in chylomicrons
    d- Conjugated bile salts are actively resorbed in the colon and returned to the liver via the portal vein
    e- Water-insoluble dietary lipid is rendered into soluble micelles through mixing with pancreatic amylase
  2. Fraink.

    Fraink. Guest

    Answer: a. (Greenfield, 2/e, pp 816) As it does with carbohydrate digestion, the gastrointestinal tract exhibits remarkable redundancy and alternative pathways to facilitate fat uptake. In the normal state, water-insoluble dietary lipid is rendered into soluble micelles through mixing with pancreatic and intestinal lipase and with bile. However, lipases of the stomach and small intestine permit absorption of approximately half of neutral dietary fat in the absence of bile and pancreatic secretion. Small breakdown products of complex fats- such as glycerol, short-chain fatty acids, and medium-chain triglycerides - can be transported directly from the jejunal mucosal cell into the portal venous system, whereas larger triglycerides, resynthesized by the mucosal cell from fatty acids, are deposited in chylomicrons and released into the lymphatic system. Enterohepatic recirculation of bile with active resorption in the ileum and secretion into the portal venous system yields an effective bile salt pool 6 to 8 times its actual volume. Normal daily losses of bile into the stool represent 10 to 15% of the total bile salt pool; these losses can usually be replaced by new synthesis in the liver. However, bile salt-wasting stages, such as inflammatory bowel disease or ileal resection, may exceed the liver’s capacity to maintain an adequate volume of bile.

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