Cystic Fibrosis

Cystic fibrosis is caused by a gene mistake (often called a gene mutation). The gene contains instructions for building a protein that controls the passage of salt across various membranes in the body. Because the gene contains faulty instructions, the protein is not built correctly and salt transport is not controlled properly. Salt transport is important for the function of many organs, including the lungs and the pancreas.

Incidence

In Australia, one in 2500 babies is born with cystic fibrosis, although it is more common in Caucasian people than among Asian or African people. Approximately 3000 people in Australia have cystic fibrosis. Every newborn in Australia is offered a blood test to check for the presence of several genetic or metabolic disorders, including cystic fibrosis. The benefit of this test is early detection, as many complications can be avoided with prompt treatment.

Symptoms

Cystic fibrosis causes mucus to be retained in the lungs. This retained mucus easily becomes infected, which obstructs and damages the airways. The infections are persistent requiring daily therapy such as antibiotics and chest physiotherapy. Many patients require admission to hospital on a regular basis. The pancreas is also affected, so it does not secrete the usual enzymes needed to digest food. Sometimes, other organs (such as the liver and the gut) are affected too. In some people the effects are mild or the disease may affect only one organ in a noticeable way. In others, the effects are severe and widespread. Most people with cystic fibrosis have a cough that produces mucus; they also have trouble digesting and absorbing nutrients from their food, so typically they are underweight.

Disease progression

Historically, most people with cystic fibrosis died in childhood due to lung damage from repeated infections. Although there is still no cure, survival has increased so that the average survival is now 36 years. This improvement is thanks to better therapies provided by a range of health professionals, aimed at slowing the progression of the disease.

Could I catch cystic fibrosis?

No. In order to have cystic fibrosis, a person must have two abnormal copies of the gene. These are inherited – one from each parent. Since your genes are fixed at birth, there is no way to ‘catch’ cystic fibrosis.

If only one abnormal gene is inherited, the disease does not occur, but the person is a carrier. Most people are unaware that they are carriers. However, if two carriers have a child, there is a 25% chance that their child will have cystic fibrosis. See diagram.

Could I be a carrier?

About one person in 25 is a carrier and would have no symptoms to suggest that status. Most babies with cystic fibrosis are born to parents who do not know they are carriers. Couples considering a pregnancy may wish to find out if they are carriers.

For people with a family history of cystic fibrosis, free testing can be arranged through the nearest cystic fibrosis clinic in a major public hospital. For people with no family history, a fee-for-service test is available. The screening co-ordinator at Genetic Health Services Victoria at the Royal Children’s Hospital in Melbourne will post you a screening pack. The test requires only a painless cheek swab that you can do yourself. Your local doctor needs to sign the request form before you post the swab back to Melbourne for testing.

What is the result of patients living longer?

Although average life expectancy for people with cystic fibrosis is still much lower than for the general population, deaths in childhood are becoming rare. For most patients, however, the cost of this extended length of life is a rigorous and time-consuming regimen of therapies, including many medications, attention to diet, and physiotherapy techniques to help clear infected mucus from the airways. Adulthood heralds the need to make many decisions, including those related to occupation, finances, travel, relationships, and parenthood. These can further impact on the person’s health and the time required to carry out treatments to maintain health.

Another issue for adults with cystic fibrosis is the development of additional health problems from chronic disease and chronic therapy. For example, chronic poor absorption of nutrients may mean that bones have low density or osteoporosis. Bone density can be further worsened by long-term therapies such as corticosteroids.

How does physiotherapy help?

Physiotherapists are heavily involved in the management of people with cystic fibrosis. Many physiotherapy techniques can be used to help clear the mucus from the airways. The physiotherapist may apply some techniques personally, and teach other techniques that can be performed independently at home. To maximise the benefit of the entire regimen, physiotherapists carefully co-ordinate these treatments with the delivery of medications to the lungs.

Exercise is another extremely important part of physiotherapy management. Exercise improves lung function and quality of life; it can also be used to increase body weight and strength. However, specific types of exercise training are required to produce these various benefits. Also, cystic fibrosis can cause many complications that require precautions or monitoring with exercise. The input of a physiotherapist is valuable in prescribing a safe exercise regimen that effectively targets the needs of each patient.

When lung disease becomes very advanced, patients may need to use a machine to help them to breathe. This treatment is called non-invasive ventilation, because it is simply delivered by a face mask which can be applied and removed by the patient as required. Physiotherapists are often involved in establishing the appropriate settings for the machine for each patient and educating them about using the machine at home and in the hospital. When patients are acutely unwell, this treatment is very effective at supporting the respiratory system back to its previous level of function. Research is currently investigating the potential benefit of this system in patients with milder lung disease.

Last Updated - Wednesday, 27 August 2008 11:36