Cystic fibrosis is the most common inherited disorder among caucasians. It is an autosomal recessive disease, and affects approximately 1/2000 live births in this population. The cystic fibrosis gene has been localized to the long arm of chromosome 7. A three base pair deletion in this location causes a phenylalanine deletion, which affects up to 75% of patients affected with this condition. Mutations at other sites within this gene are found in the remainder of the cystic fibrosis population.

This condition alters exocrine secretions throughout the body, affecting multiple organ systems. The elevated sodium, potassium and chloride concentration within sweat is used to identify patients diagnosed with cystic fibrosis. The majority of patients are diagnosed in infancy or childhood, but some patients are not diagnosed until adulthood.

Treatment of the condition and its accompanying ailments has improved, however the illness continues to shorten the life expectancy of its victims. The average age of death is about 20 years old, but many live into their thirties or forties. Almost 100 percent of males with cystic fibrosis are infertile, and women also exhibit decreased fertility.

Cystic fibrosis is a multi-organ system disorder, and the pulmonary and gastrointestinal systems account for particularly morbid complications. Mucus plugging leads to bronchiectasis, chronic bronchitis and recurrent pulmonary infections. Staphylococcus aureus and Haemophilus influenzae infect a large number of these patients, and Pseudomonas aeruginosa colonizes the lungs of nearly all cystic fibrosis patients. Late manifestations of pulmonary disease include air trapping, pulmonary hypertension, and cor pulmonale.

In the gastrointestinal system, pancreatic insufficiency leads to fat and protein malabsorption. Fortunately, oral enzymes can be used to treat the majority of these patients. Some patients experience biliary tract disorders and recurrent episodes of pancreatitis due to obstruction of the bile and pancreatic ducts. Very few experience endocrine deficiencies as a result of the disease. . On axial imaging of the abdomen, a very small and largely fatty-replaced pancreas is a common finding. This can be accompanied by changes due to portal hypertension, such as varices and hypersplenism. Five percent of patients are born with meconium ileus – intestinal obstruction due to inspissated meconium within the terminal ileum. Later in life, thickening of the bowel wall can be identified.