Cystic fibrosis (CF) is the most common lethal, genetic disease in the white population. CF occurs in about 1 of every 2000 live births in the United States and 5% of the general population are gene carriers.1 CF is a disease of the epithelial cells in the body; especially those lining the intestinal tract and airways of the lungs. Normally, epithelial cells transport chloride through the cystic fibrosis transmembrane regulator (CFTR) with sodium and water following the ion flux. CF is the loss of the function of the CFTR with defective movement of Cl and water in the body. Thus, the composition of fluid secreted by the pancreas, hepatobiliary tree, reproductive tract, sweat glands, and the airways is thick and leads to obstruction with malfunction. This malfunction eventually leads to widespread organ system disease (Table 44-1).
TABLE 44-1 Organ System Effects of Cystic Fibrosis ||Download (.pdf)
TABLE 44-1 Organ System Effects of Cystic Fibrosis
|Organ Obstruction||Malfunction||Clinical Effect|
|Pancreatic duct||Duct obstruction||Enzyme deficiency, maldigestion|
|Biliary duct||Duct obstruction||Cirrhosis, portal hypertension, esophageal varices|
|Intestines||Viscous secretions||Distal intestinal obstructive syndrome (DIOS)|
|Pulmonary||Viscous secretions||Obstruction, infection|
|Sweat glands||Fail to reabsorb Na ("salty taste of skin")||Hyponatremia|
|Reproductive||Obstruction epididymis, vas deferens, seminal vesicles||Aspermia|
|Obstruction cervix||Decreased fertility|
|Bone, joint||Unknown||Arthritis, osteopenia|
Clinical presentation of CF patients can be divided into early disease and disease later in life. Early disease is usually milder while later disease is more advanced and severe. Early obstruction in the gastrointestinal system manifests as abdominal distention, pain, vomiting, and change in stool output. Early maldigestion, due to lipase deficiency, produces stools with high fat content known as steatorrhea. Symptoms of steatorrhea in the patient are stools with foul odor, bulkiness, greasiness, and more frequent in number. Late maldigestion leads to varying degrees of malnutrition. Late pancreatic disease leads to a relative insulin deficiency known as cystic fibrosis-related diabetes (CFRD) which can be symptomatic or can present as untreated diabetes mellitus type 2. Late disease in the biliary tract leads to obstruction and liver failure (Table 44-2).
TABLE 44-2 Early Versus Late Disease in CF Patients ||Download (.pdf)
TABLE 44-2 Early Versus Late Disease in CF Patients
|Organ Malfunction||Early Disease||Late Disease|
|Obstruction||Distention, pain, nausea and vomiting||DIOS, liver failure, CFRD|
|Maldigestion||Steatorrhea, malnutrition||Severe malnutrition|
|Obstruction||Cough, ↑sputum||COPD, cor pulmonale|
|Infection||Acute exacerbations||Permanent ↓PFTs|
Pulmonary disease can also be divided into early and late disease. Early obstruction in the pulmonary system leads to coughing, sputum production, wheezing, retractions, tachypnea, dyspnea, and cyanosis. Early pulmonary infection begins with a slow cycling pattern with well-being alternating with pulmonary deterioration known as exacerbations. These early exacerbations are commonly caused by Staphylococcus aureus, Haemophilus influenzae, and Pseudomonas aeruginosa with later infections caused by more resistant ...