The Causes and Pathophysiology of Cystic Fibrosis

Introduction
Cystic fibrosis is a genetic condition with a primary symptom of excessive mucous production and resulting lung infections. It is “the most common fatal hereditary lung disease,” (Mall & Hartl, 2014, p. 1042). Symptoms and severity of the disease varies, but all cases are inherited. On the genetic level, cystic fibrosis is an “autosomal recessive disease caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR),” (Stoltz, Meyerholtz & Welsh, 2015, p. 351). There is no cure for cystic fibrosis, which can be deadly, but treatments for the disease have become more advanced, less invasive, and more effective.
Etiology and Risk Factors
Because cystic fibrosis is congenital, disease etiology is genetic. The disease is most prevalent among Caucasians of Western European ancestry. Cystic fibrosis is known as a Mendelian condition, a disease that is actually caused by only one single gene dysfunction or mutation (Cutting, 2015). Being a carrier of CFTR mutations is the only known risk factor for the disease. The disease can be present long before symptoms manifest (Stoltz, Meyerholtz & Welsh, 2015). Therefore, genetic testing may be a critical component in ensuring early interventions to minimize symptom severity and promote longer and better quality of life for patients. In the United States, newborns are routinely screened for cystic fibrosis for this very reason.
Pathophysiological Processes
The pathophysiological processes of cystic fibrosis are relatively straightforward, involving excessive thick mucous production on a cellular level. The excessive mucous clogs essential airways and digestive tracts, leading to lung infections, inability to breathe, and inability to eat or process food.
In a healthy body, cells produce mucous, sweat, and other bodily fluids for lubrication and other functions. Cystic fibrosis is a condition whereby the genetic abnormality causes the mucous secretions to become abnormally and detrimentally thick. The thick secretions clog up critical passageways in the lungs and pancreas. In fact, CFTR dysfunction “may be implicated in the pathogenesis of chronic obstructive pulmonary disease,” (Mall & Hartl, 2014, p. 1042).
Cystic fibrosis “alters the electrophysiological properties across airway epithelia,” (Stoltz, Meyerholtz & Welsh, 2015, p. 353). In addition to air passage clogging, which leads to impeded breathing and lung infections, people with cystic fibrosis also experience digestive problems that can result in malnutrition-related illnesses.
Clinical Manifestations and Complications
Because of rigorous screening procedures in the United States, cystic fibrosis is detected in infancy through genetic, blood, and sweat tests. Respiratory complications and signs include wheezing and coughing, as well as other pulmonary symptoms like chest pain and asthma. Complications include lung infections and pancreatic infections, as well as malnutrition and related problems due to the obstruction of digestive passageways. Constipation, inability to grow or gain weight in childhood, improper bowel movements, persistent cough, and other complications can be detected early and mitigated.
Diagnostics
Diagnostics have come a long way, allowing healthcare workers to detect the disease early. Genetic tests are ideal, and help prepare the family for how to mitigate the problems and complications associated with the disease. Changes to lifestyle and environment may minimize symptom severity but not necessarily provide lasting relief or in any way reverse the progression of the disease. Unfortunately, cystic fibrosis is fatal and there is no cure. Life expectancy is low. Diagnosis of cystic fibrosis does entail an acceptance of what the disease entails.






References

Cutting, G.R. (2015). Cystic fibrosis genetics: from molecular understanding to clinical application. Nature Reviews Genetics 16: 45-56.
Mall, M. A. & Hartl, D. (2014). CFTR: cystic fibrosis and beyond. European Respiratory Journal 2014(44): 1042-1054.
Stoltz, D.A., Meyerholtz, D.K. & Welsh, M.J. (2015). Origins of cystic fibrosis lung disease. The New England Journal of Medicine 372(4): 351-362.