CF Effects on the GI Tract and Liver

Notes on a talk given at the Annual CFRI Conference by Dr. Dorsey Bass

Fall 1995

Dr. Dorsey Bass, Assistant Professor of Pediatric Gastroenterology at Stanford University Medical School and practicing physician at Packard Children's Hospital at Stanford, introduced complications of the GI tract in patients with CF. Many are very common and require appropriate surveillance by both physicians and patients.

Beginning in the mouth, Bass noted that although CF salivary glands are enlarged, there are not many symptoms or problems. Moving on to the esophagus, he talked about Gastro-Esophageal Reflux (GER), a common manifestation in CF because of the abnormal amount of gastric acid in the esophagus, hypersecreted by the stomach. Added pressure from the extra work of breathing further exacerbates the condition. Patients experience heartburn, chest and abdominal pain and esophagitis (inflammation, bleeding and strictures). GER is diagnosed from symptoms of chronic heartburn. Also, doctors can order tests such as a barium swallow, an upper GI, or an endoscopy (which shows the degree of damage). Gastric and duodenal disease, which is also caused by high gastric hypersecretion and low pancreatic bicarbonate secretion, were also mentioned. Treatments suggested for GER included elevating the head of the bed, reducing caffeine, chocolates and fat in the diet, prokinetic drugs such as cisapride (also known as Propulsid), drugs which inhibit acid secretion such as ranitidine (known as Zantac) and omeprazole (also known as Prilosec), and in very severe cases fundoplication, a rather complex surgery.

Bass discussed the thick mucus layer over the walls of the CF small and large intestines and added that they were not well hydrated. Intestinal glands were frequently obstructed with mucus, and intraluminal electrolytes were abnormal. This is a setup for many diseases. Small bowel overgrowth is one such problem which tends to occur in surgery patients who have had their ileocecal valve removed. Treatment is most effective if directed against anaerobic bacteria, and surgical repair only when feasible. Three kinds of newborn intestinal obstructions were discussed, which afflict about 10 percent of the CF patients: meconium ileus (obstruction of terminal ileum by thick meconium, diagnostic of CF), meconium peritonitis (intestinal perforation which occurs in utero and requires immediate surgery, also diagnostic of CF), and meconium plug (which occurs more in the large bowel and is less indicative of CF, only 10 percent of cases). Constipation is yet another problem that is especially common in adults with CF. Slightly different than constipation in the general population, the CF condition persists even after a bowel movement. Stool softeners and enemas help in relieving the symptoms. A more extreme form of constipation, Distal Intestinal Obstruction Syndrome (DIOS), formerly called meconium ileus equivalent, is an obstruction in the intestines. Signs include a distended, hardened belly, extreme discomfort and vomiting. Dr. Bass said treatments include Fleets Phospho soda, Go Lytely, hypertonic enemas, Mucomyst by mouth, g-tube or enema, or for patients with severe recurring problems an Ileal tube could be installed in the lower abdomen (similar to the G-tube) so patients could perform regular flushings with Mucomyst.

Without treatment the situation could become more severe, and intussusception could occur (a condition in which part of the intestine telescopes in on itself, forming a tube within a tube), which is extremely painful. Dr. Bass also mentioned rectal prolapse which is common in young CF patients and is an indicator of CF. With proper enzyme therapy, the problem usually corrects itself.

Focusing on the pancreas, Dr. Bass pointed out that pancreatic function could be assessed by checking for foul, bulky stools. If more information is needed, a duodenal fluid analysis, fecal fat study or PABA test can be performed. Pancreatic insufficiency is treated with enzyme therapy. Glucose intolerance (diabetes) occurs as the advanced pancreatic destruction "strangles" the insulin producing cells in the pancreas. Steroid therapies or IV sugars may precipitate this condition. Six to ten percent of older CF patients require insulin, however diseases commonly associated with juvenile diabetes are rare.

Dr. Bass discussed several problems that might afflict the CF liver. The first, prolonged neonatal jaundice, usually resolves by itself in infancy with no lingering effects. Fatty liver (an enlarged liver) is commonly a nutritional disorder, caused by either over or under nutrition. It is generally not serious and will resolve itself when proper nutritional status is restored. Finally, biliary cirrhosis is the most dangerous liver disease in CF patients. Autopsy results show that 25 percent of CF patients have some evidence of biliary cirrhosis. However, only five percent of people with CF actually display symptoms of the disease. Sometimes a physical exam will determine a firm and nodular liver. Further lab tests can show elevated alkaline phosphatase, even while bilirubin is often normal. As the disease progresses, the liver becomes more scarred causing portal hypertension, serious bleeding in the GI tract and an enlarged spleen. With complete liver failure comes jaundice, blood clotting failures, and edema. Early treatment includes good nutrition and close clinical follow-up, avoidance of aspirin, ibuprofen and alcohol. Ursodeoxycholic acid can sometimes help, and in extreme cases, liver transplant (although Dr. Bass noted that good pulmonary function was a prerequisite) is necessary.

Dr. Bass ended with a discussion of the gall bladder. In people with CF, the gall bladder is frequently abnormally small. Ten to 25 percent of CF patients experience gall stones, but usually they are asymptomatic. If there are no symptoms, they are not treated. There can, however, be complications such as cholecystitis (inflammation of the gall bladder) caused by the gallstone obstructing the outlet. Ursodeoxycholic acid can be used to dissolve it, but this takes a long time and the problem usually recurs if the medication is discontinued. Doctors are now using laparoscopic surgery and ERCP (endoscopic retrograde cholangiopancreatography) to dissolve the stones. In severe cases, biliary flushing through an abdominal puncture with solvents has been used, but doctors are opting for the less intrusive methods mentioned above.

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