Cystic Fibrosis: Causes, Treatments, and the Search for a Cure

Introduction

One of the more challenging disorders identified in the 20th century is cystic fibrosis, with the cause of the disease only being discovered relatively recently. Although improved multifaceted healthcare interventions have allowed many cystic fibrosis sufferers to live much longer than even a few years ago, life expectancies for people with this condition remain far lower than those of the general population, and the condition itself detracts from the quality of life in a number of ways for the sufferer and family members alike. Unfortunately, a cure for cystic fibrosis remains elusive, and many people who suffer from the disease will still succumb to the cumulative effects of repeated infections over time. To determine what progress is being made in this area, this paper provides an overview of cystic fibrosis, including its cause, symptoms, and current treatment protocols, followed by a discussion of current research initiatives aimed at identifying new treatment interventions.

Background and Overview of Cystic Fibrosis

Cystic fibrosis was first identified as a specific disorder in 1938; however, the precise cause of the disorder remained unknown until the cystic fibrosis (CF) gene was identified in 1989 (Schubert & Murphy, 2005). According to Schubert and Murphy, "Mutations in this gene lead to the defective production of a salt-regulating protein known as the CF transmembrane conductance regulator. As a result, chloride ions and water cannot flow properly through cell membranes, leading to the production of thick, sticky mucus" (p. 35). The disease affects a number of bodily organs, but tends to do the majority of its damage to the lungs and pancreas. As a result, the most debilitating aspects of the disease involve difficulties in breathing due to effects on the pulmonary system and, for about 90% of those with CF, difficulty in digestion due to effects on the pancreas (Schubert & Murphy).

Cystic fibrosis is an autosomal recessive disease — that is, it involves a chromosome that is not a sex chromosome — and occurs in about one in 3,400 live births among Caucasians. Its incidence is lower among people of other backgrounds; approximately one in 30 white individuals and one in 60 Black individuals are carriers (Wilfond, 1995). One of the more challenging aspects of managing the disease is the fact that carriers can be asymptomatic and will probably not have a known family history of the disease. In cases where two asymptomatic parents are involved, they have a 25% chance with each pregnancy of having a child with cystic fibrosis (Wilfond).

According to Wilfond (1995), "Cystic fibrosis is caused by a defective protein that results in thickened secretions in the respiratory, digestive, and reproductive systems. People with the disease often have trouble digesting food and may be malnourished, are commonly infertile, and over time, have recurrent lung infections that cause gradual deterioration of lung function" (p. 21).

As the result of improved medical care, people who suffer from cystic fibrosis are managing to overcome the more deleterious effects of the disease and live longer than in years past (Wilfond). Just 30 years ago, the median survival age for those with cystic fibrosis was 18 years; by 1990 it was 28 years, and current treatment techniques can help some sufferers live well into their 50s (Wilfond). Despite this progress, Schubert and Murphy (2005) report that the life expectancy for CF sufferers remains woefully short of the normal life expectancy for the general population. According to these authors, "The first sizeable cohort of people living with cystic fibrosis (CF) has now reached adulthood. Gradual improvements in the diagnosis and treatment of the disease have increased life expectancy to approximately 32 years. Members of this cohort have lived all their lives near, at, or slightly beyond life expectancy" (p. 35). Rather than a cure, these gains in life expectancy and quality of life have been accomplished through treatment interventions aimed at minimizing the adverse effects of the disease on bodily organs.

Symptoms and Physiological Impact

The typical respiratory symptoms related to cystic fibrosis include coughing, the production of thick sputum and associated decreased pulmonary function, congestion, and shortness of breath. In addition, the concentration of mucus restricts the oxygenation of the blood, placing additional stress on the heart and other organs, which frequently results in clubbing of the fingers and toes (Schubert & Murphy). As Reid (1996) emphasizes, "The major problem of cystic fibrosis, the number one genetic killer disease of children in the United States, is that the body overproduces thick, sticky mucus. The mucus blocks the pancreatic ducts, which impedes the flow of the pancreatic juices from the pancreas into the duodenum of the small intestines. Food cannot be properly digested. Without treatment, children with cystic fibrosis suffer from malnutrition and constant diarrhea" (p. 27).

Moreover, CF patients tend to experience cycles of infection and inflammation of increasing frequency and severity as a result of their inability to clear mucus from their lungs. The cumulative effects of lung scarring compound this problem, and the majority of CF fatalities are the result of opportunistic infections (Schubert & Murphy).

Based on their difficulties in digesting food, Reid reports that some cystic fibrosis patients are prescribed enzyme preparations that help mitigate the disease's effects on the pancreas. In this regard, Reid explains, "Pancreatic juices contain enzymes for digesting all three major food types (proteins, carbohydrates and fats), as well as quantities of bicarbonate ions, which play an important role in neutralizing the acid emptied by the stomach into the duodenum" (p. 28). The addition of these bicarbonate ions helps cystic fibrosis patients metabolize ingested food more normally, as well as serving to neutralize large accumulations of stomach acid (Reid).

Conclusion

The research showed that treatment for cystic fibrosis continues to evolve, but remains largely restricted to frequently aggressive therapies designed to mitigate the effects of CF on the various bodily organs it affects, including the lungs, heart, and pancreas. Because cystic fibrosis is a genetic disease, researchers have increasingly sought gene-replacement therapies that can cure rather than merely treat the condition. Unfortunately, the research is consistent in emphasizing that such a cure remains a distant goal, perhaps decades away. In the meantime, clinicians recommend a multidisciplinary approach that embraces a multifaceted treatment protocol for the wide range of symptoms typically associated with the disease, and these techniques have provided many CF sufferers with a longer and better quality of life.

The cumulative effects of cystic fibrosis, however, tend to make symptomatic treatments less effective over time, and opportunistic infections remain the primary cause of premature death among this population. While the race for a cure continues, the enormously debilitating effects of cystic fibrosis on the individual — as well as on surrounding family members — mean that the burden of CF is not restricted to patients alone, but extends to those around them in ways that can adversely affect quality of life for all concerned. Therefore, it makes good sense to extend future research into how family members can provide the levels of support needed for CF sufferers while protecting themselves from the burnout that is typically associated with the provision of such demanding day-to-day healthcare needs.

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