 | | | 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
The small intestine—comprised of the duodenum, jejunum and ileum—is the primary organ involved in absorption of nutrients. Many cells involved in the digestion and absorption process secrete mucus, digestive enzymes, and hormones. The innermost layer of the small intestine also has small, finger-like projections called villi, which are designed to absorb nutrients. Abnormal Function
CF affects the small intestine. Decreased pancreatic secretions limit the breakdown of fats, which cannot be absorbed by the small intestine because they are too large. The absorption of fats is further diminished by the inability of the ileum to absorb bile salts that aid in the digestion of fats. The absorption of fat-soluble vitamins A, D, E, and K is also diminished, leading to malnutrition. Often, a CF patient’s small intestine is unable to neutralize the acidic contents delivered from the stomach. This further impairs the activity of pancreatic secretions and digestion. Also, these acidic contents can erode of the lining of the small intestine and lead to damage. Large Intestine
The large intestine is involved in the reabsorption of water from the GI tract and is also the site of feces formation and excretion. The large intestine spans the perimeter of the abdomen. Distal Intestinal Obstruction Syndrome
The large intestine does not function normally in CF. Incompletely digested proteins, sugars, and fats, decreased electrolytes and water content make the feces very thick. Patients are prone to intestinal impaction and obstruction. 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 of patients will have recurrences. Prompt recognition is essential for proper treatment. Physical exam and X-rays of the abdomen can diagnose this blockage. Treatment varies based upon the severity of the symptoms and degree of intestinal obstruction. Intussusception
Intussusception, the telescoping of one portion of the intestine into another, occurs rarely in CF patients. But it can lead to intestinal obstruction 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. A potentially life-threatening infection in the blood stream can follow. Symptoms include severe abdominal pain, fever, low blood pressure, and bloody stools. Occurring most commonly in children with and without CF, the condition affects about one percent of CF adults. Adequate hydration and 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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