 | | | Select from the menu above to compare normal digestion to
digestion with CF.
(A) After food is broken down by enzymes, nutrients are normally absorbed from the intestine,
(B) into the blood stream.
(C) With CF the absorption is
impaired by the presence of thick secretions. |
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Small Intestine
Normal Function
The small intestine, which has the job of absorbing nutrients, is comprised of the duodenum, jejunum, and ileum. Cells involved in digestion and absorption secrete mucus, digestive enzymes, and hormones. The innermost layer of the small intestine absorbs nutrients. Abnormal Function in Cystic Fibrosis
Since fat is not easily broken down by CF patients, fat cannot be absorbed by the small intestine because the particles are too large. The absorption of vitamins A, B12, D, E, and K is also affected in CF patients because these vitamins are fat-soluble. Without these vitamins, CF patients may become undernourished. Also, a CF patient’s small intestine cannot neutralize stomach acids, which can erode the lining of the small intestine and lead to peptic ulcers. Large Intestine
Normal Function
The large intestine reabsorbs water from the GI tract, forms and pushes feces through the GI tract. Distal Intestinal Obstruction Syndrome
Incompletely digested proteins, sugars and fats, and decreased water content make the feces very thick, making patients prone to intestinal blockages. Symptoms include decreased stool output, abdominal pain and distention, nausea, and vomiting. Previously known as meconium ileus equivalent, the newer terminology is distal intestinal obstruction syndrome, or DIOS. About 10 to 20 percent of CF patients will have DIOS at least once, and up to 3.5 percent will have repeat episodes. Physical exam and X-rays of the abdomen can diagnose this blockage. Treatment varies based upon the severity of the obstruction. Intussuseption
Intussusception, the telescoping of one portion of the intestine into another, occurs rarely in CF patients. But it can cause intestinal blockages when fecal matter attaches to the intestinal wall and forces the intestine to fold incorrectly, leading to decreased blood flow. Eventually, part of the intestinal wall can rupture, releasing fecal matter into the abdomen. This will cause a potentially life-threatening infection in the blood stream. Symptoms include severe abdominal pain, fever, low blood pressure, and bloody stools. This happens mostly to children with and without CF, but can affect approximately 1 percent of CF adults. Drinking enough fluids and taking stool softeners are necessary for prevention. Colon Cancer
Compared with the general population, CF patients have a similar risk of cancer. But when it comes to colon cancer and other intestinal cancers, studies show, CF patients have an increased risk. The best screen is a colonoscopy. 
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