Cystic Fibrosis: A Quick Introduction
Cystic Fibrosis is the commonest inherited disorder in Caucasian peoples. One in twenty-five carries the defective recessive gene, and the incidence is approximately one in 2500 live births in the United Kingdom. It's a major interest of mine because besides being a doctor, I have cystic fibrosis. I therefore know what it's like from both sides.
People who have CF produce a defective version of a protein called CFTR (Cystic Fibrosis Transmembrane Conductance Regulator). This is responsible for transport of salts and water across cell membranes. This means that in certain parts of the body, the secretions lack water, becoming sticky. The main clinical manifestations are
If left untreated, the lungs become progressively damaged by chronic infection leading to bronchiectasis, respiratory failure and death. People with cystic fibrosis often have problems with organisms not usually associated with lung infections, including Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia cepacia, Stenotrophomonas maltophilia and non-tuberculous mycobacteria
However with modern treatments the prognosis of the disease is improving. In 1960, most children born with CF lived less than a year. Children with CF born in 1995 could expect a median survival around 40 years. This has meant that the number of sufferers, and particularly the number of adults, has grown rapidly. There are currently over 6000 people with CF in the United Kingdom, and almost half of these are adults. But not only is survival improving - the quality of life is also good. A majority of adult patients with CF are able to work or study full time. CF patients in the United Kingdom achieve the same or a better academic level than the normal population of the same age. CF patients in the United Kingdom also achieve 80% of the employment rate in the normal population for their age and sex.
This is not to minimise the effect of the disease upon individuals and their families. Frequently, people achieve these things despite the difficulties associated with a long-term disease such as missing time from school, education or work, having to take time-consuming treatment every day, and frequent spells of illness and admissions to hospital.
Treatment is centred around
Due to the nature of the infecting organisms, antibiotic treatment frequently has to be given intravenously (either regularly or for exacerbations) or via nebuliser (as daily maintenance treatment). Dornase alpha is a new mucolytic drug that makes secretions thinner and easier to clear in a proportion of patients. Other drugs are under development in this area.
An exciting new development is the possibility of correcting the underlying abnormality in salt and water transport in patients with CF. Two areas are under study: insertion of a normal gene to correct the basic defect (gene therapy) and development of drugs that correct salt and water transport abnormalities. Other areas of study include treatments that reduce the inflammation and lung damage associated with chronic infection: these include anti-inflammatory drugs, some of which are readily available and already licensed for use in other conditions.
Despite the excellent treatment now available, some patients with CF inevitably suffer irreversible, severe lung damage leading to respiratory failure. In some selected patients, this can be treated by lung or heart-lung transplantation. A very small proportion of CF patients suffer liver failure. Some of these may also be treated by liver transplantation.