Cystic Fibrosis

Cystic Fibrosis

Cystic fibrosis (CF) is the most common fatal autosomal reces-sive disease among the Caucasian population. An individual must inherit a defective copy of the CF gene (one from each parent) to have CF. One in 31 Americans are unknowing symptom carriers of this gene (Katkin, 2002). The frequency of CF is 1 in 2,000 to 3,000 live births, and there are approximately 30,000 children and adults with this disease in the United States (Cystic Fibrosis Foundation, 2002). Although CF was once considered a fatal childhood disease, approximately 38% of people living with the disease are 18 years of age or older (Cystic Fibrosis Foundation, 2002). Cystic fibrosis is usually diagnosed in infancy or early child-hood, but patients may be diagnosed later in life. For individuals diagnosed later in life, respiratory symptoms are frequently the major manifestation of the disease.

Pathophysiology

This disease is caused by mutations in the CF transmembrane conductance regulator protein, which is a chloride channel found in all exocrine tissues (Katkin, 2002). Chloride transport prob-lems lead to thick, viscous secretions in the lungs, pancreas, liver, intestine, and reproductive tract as well as increased salt content in sweat gland secretions. In 1989, major breakthroughs were made in this disease with the identification of the CF gene. The ability to detect the common mutations of this gene allows for routine screening for this disease as well as the detection of carri-ers. Genetic counseling is an important part of health care for couples at risk.

Airflow obstruction is a key feature in the presentation of CF. This obstruction is due to bronchial plugging by purulent secre-tions, bronchial wall thickening due to inflammation, and, over time, airway destruction (Katkin, 2002). These chronic retained secretions in the airways set up an excellent reservoir for contin-ued bronchial infections.

Clinical Manifestations

The pulmonary manifestations of this disease include a productive cough, wheezing, hyperinflation of the lung fields on chest x-ray, and pulmonary function test results consistent with obstructive airways disease (Katkin, 2002). Colonization of the airways with pathogenic bacteria usually occurs early in life. Staphylococcus au-reus and Haemophilus influenzae are common organisms duringearly childhood. As the disease progresses, Pseudomonas aeruginosa is ultimately isolated from the sputum of most patients. Upper res-piratory manifestations of the disease include sinusitis and nasal polyps.

Nonpulmonary clinical manifestations include gastrointesti-nal problems (eg, pancreatic insufficiency, recurrent abdominal pain, biliary cirrhosis, vitamin deficiencies, recurrent pancreati-tis, weight loss), genitourinary problems (male and female infer-tility), and clubbing of the extremities.

Assessment and Diagnostic Findings

Most of the time, the diagnosis of CF is made based on an ele-vated result of a sweat chloride concentration test, along with clinical signs and symptoms consistent with the disease. Repeated sweat chloride values of greater than 60 mEq/L distinguish most individuals with CF from those with other obstructive diseases. A molecular diagnosis may also be used in evaluating common genetic mutations of the CF gene.

Medical Management

Pulmonary problems remain the leading cause of morbidity and mortality in CF. Because chronic bacterial infection of the air-ways occurs in individuals with CF, control of infections is key in the treatment. Antibiotic medications are routinely prescribed for acute pulmonary exacerbations of the disease. Depending upon the severity of the exacerbation, aerosolized, oral, or intravenous antibiotic therapy may be used. Antibiotic agents are selected based upon the results of a sputum culture and sensitivity. Pa-tients with CF have problems with bacteria that are resistant to multiple drugs and require multiple courses of antibiotic agents over long periods of time.

Bronchodilators are frequently administered to decrease air-way obstruction. Differing pulmonary techniques are used to en-hance secretion clearance. Examples include manual postural drainage and chest physical therapy, high-frequency chest wall os-cillation, and other devices that assist in airway clearance (PEP masks [masks that generate positive expiratory pressure], “flutter devices” [devices that provide an oscillatory expiratory pressure pattern with positive expiratory pressure and assist with expecto-ration of secretions]).

Inhaled mucolytic agents such as dornase alfa (Pulmozyme) or N-acetylcysteine (Mucomyst) may also be used. These agents help to decrease the viscosity of the sputum and promote expec-toration of secretions.

To decrease the inflammation and ongoing destruction of the airways, anti-inflammatory agents may also be used. These may include inhaled corticosteroids or systemic therapy. Other anti-inflammatory medications have also been studied in CF. Ibupro-fen was studied in children with CF and some benefit was demonstrated, but there is little information on its use in young or older adults with CF (Katkin, 2002).

Supplemental oxygen is used to treat the progressive hypox-emia that occurs with CF. It helps to correct the hypoxemia and may minimize the complications seen with chronic hypoxemia (pulmonary hypertension).

Lung transplantation is an option for a small, select popula-tion of CF patients. A double lung transplant technique is used due to the chronically infected state of the lungs seen in end-stage CF. Because there is a long waiting list for lung transplant recip-ients, many patients die while awaiting a transplant.

Gene therapy is a promising approach to management, with many clinical trials underway. It is hoped that various methods of administering gene therapy will carry healthy genes to the damaged cells and correct defective CF cells. Efforts are under-way to develop innovative methods of delivering therapy to the CF cells of the airways.

Nursing Management

Nursing care of the adult with CF includes assisting the patient to manage pulmonary symptoms and to prevent complications of CF. Specific nursing measures include strategies that promote removal of pulmonary secretions; chest physiotherapy, including postural drainage, chest percussion, and vibration, and breathing exercises are implemented and are taught to the patient and to the family when the patient is very young. The patient is reminded of the need to reduce risk factors associated with respiratory in-fections (eg, exposure to crowds and to persons with known in-fections). The patient is taught the early signs and symptoms of respiratory infection and disease progression that indicate the need to notify the primary health care provider.

The nurse emphasizes the importance of an adequate fluid and dietary intake to promote removal of secretions and to ensure an adequate nutritional status. Because CF is a life-long disorder, pa-tients often have learned to modify their daily activities to ac-commodate their symptoms and treatment modalities. As the disease progresses, however, assessment of the home environment may be warranted to identify modifications required to address changes in the patient’s needs, increasing dyspnea and fatigue, and nonpulmonary symptoms.

Although gene therapy and double lung transplantation are promising therapies for CF, they are limited in availability and largely experimental. As a result, the life expectancy of adults with CF is shortened. Therefore, end-of-life issues and concerns need to be addressed in patients when warranted. For the patient whose disease is progressing and who is developing increasing hypoxemia, preferences for end-of-life care should be discussed, documented, and honored. Patients and family members need support as they face a shortened life span and an uncertain future.