Basic aspects of cystic fibrosis.

Cystic fibrosis (CF) is manifestly a disease of the exocrine organs (1) to which the respiratory, digestive, and reproductive tracts are hereby included as honorary members. In years past, few individuals with CF survived infancy. Up to 10% of affected children died shortly after birth as a result of complications from meconium ileus, and survivors, who were typically malnourished, usually succumbed to repeated and persistent lung infections. These problems can now be ameliorated, but the underlying defect remains (Fig. 1). In CF, the lungs lose their ability to maintain a sterile surface and are gradually destroyed by ineradicable colonies of bacteria, typically Pseudomonas, which convert to a mucoid form (2). The intestinal lining appears to secrete less fluid than normal andis, therefore, susceptible to blockade fromimproperly dehydrated stools (34) . This can lead to meconium ileus or its equivalent, but the tendency for stools to be dehydrated is often more than offset by the presence of steatorrhea, which is secondary to reduced secretion of pancreatic fluid (6-8). Additional symptoms that are almost invariably present include the blockage and eventual degeneration of the vas deferens in males (9), dehydrated cervical mucus and a failure of the mucus to show appropriate hydration during ovulation in females (lo), and greatly elevated concentrations of Na+ and C1in the sweat (11,12).