Bronchiectasis is a chronic disease of the lungs. It is caused by repeated damage to the airways of…
What is cystic fibrosis?
Cystic fibrosis is an inherited genetic disorder. It is caused by a gene mutation that causes cells to secrete an abnormally thick and sticky mucus. The mucus interferes with the normal functions of the lungs and airways, and affects other organs of the body including those of the digestive system and the skin. It also makes the affected organs prone to infection.
Cystic fibrosis appears mainly during childhood and early adulthood. It is a serious medical condition that can lead to premature death. While it cannot be cured, it can be managed successfully with proper treatment.
Many organs and tissues of our body have glands that secrete mucus. This watery substance forms layers that keep the linings of our internal organs moist and also helps trap and remove harmful foreign substances and microbes.
In cystic fibrosis a gene called CFTR, which plays a vital role in mucus production, is faulty. The gene makes the CFTR protein, which is essential for balancing the salt concentration in the body's cells. When it does not work properly, the cells that produce the mucus do not secrete enough water, resulting in mucus that is dense, thick and sticky.
This type of mucus clogs up the lungs and makes it hard for them to operate. The mucus can also block tubes in the pancreas, which affects normal digestion. It also provides a rich breeding ground for bacteria, so infections are common.
About 70,000 people have cystic fibrosis in the world today.  The condition is the most common hereditary disease for people of northern European descent and is uncommon amongst other types of populations.
Millions of people of northern European ancestry carry a single defective copy of the CFTR gene, without developing cystic fibrosis. The CFTR gene exists as two copies and in these individuals (known as carriers), their second copy is healthy. For an individual to develop cystic fibrosis, two copies of the defective CFTR gene are required. This can occur when two carriers, each with one defective CFTR gene, have a child who inherits two defective genes. The chance of this occurring is one-in-four.
Cystic fibrosis can appear in many forms. This is because the CFTR gene can have more than 1500 mutations, each with a unique effect on the gene's function. As a result, cystic fibrosis varies between people; it can be mild to severe, and appear in different stages of life. In most people, the effects on the lungs are the most serious, but for some people the digestive system is the most affected.
Signs and symptoms
The main signs and symptoms of cystic fibrosis occur in the respiratory and digestive systems.
Signs and symptoms in the respiratory system:
- Breathing difficulties, such as shortness of breath, wheezing and rapid exhaustion during physical activity;
- Persistent, nagging coughs;
- Repeated lung infections, such as pneumonia, and;
- Sinusitis, bronchitis and other types of inflammation of the airways.
Signs and symptoms in the digestive system
The mucus blocks the pancreatic tubes, preventing the digestive enzymes from the pancreas from reaching the stomach and intestines. These enzymes are necessary for normal digestion. Without this function a range of the following digestion-related conditions can develop:
- Stomach pain;
- Foul-smelling stools;
- Intestinal blockage, often detected in infants;
- Malnutrition, and;
- Poor growth in young children.
Other signs and symptoms
- Very salty sweat;
- Metabolic syndromes associated with salt loss;
- Abnormal heartbeat;
- Clubbing of fingers - enlarged fingernails and toenails, and;
- Low fertility in adults, especially men.
Methods for diagnosis
The diagnosis of cystic fibrosis combines two approaches:
- Testing for the gene mutations that cause the condition, and;
- Testing for the clinical signs.
Almost all cases of cystic fibrosis are diagnosed shortly after birth through routine screening. However, some infants show only the milder signs of cystic fibrosis. These signs can be hard to detect early, so clinical testing may be needed.
Newborns and prospective parents can be checked for the presence of a mutated CFTR gene from a tissue sample. The test can also specify the type of the CFTR mutation present.
Genetic tests for cystic fibrosis include:
Couples planning a pregnancy, who have family histories of cystic fibrosis, may choose to check whether they are carriers of a mutated CFTR gene. This test is performed on a sample of saliva or blood.
In many countries, screening of newborns for cystic fibrosis, and other genetic conditions after birth, is a routine procedure. A small blood sample is taken by pricking the baby's heel which then analysed.
Clinical tests assess the impact of cystic fibrosis on the body. These tests can include:
This is the traditional clinical test for cystic fibrosis. A doctor will induce sweating on a small patch of skin with a weak and painless electrical current, which is then analysed for the salt content.
An X-ray of the chest can be used to check for lung inflammation and other typical signs of cystic fibrosis.
Numerous other tests can be performed depending on the regions of the body that are affected by cystic fibrosis. These can include blood tests, scans and procedures, such as bronchoscopy.
Types of treatment
There is currently no cure for cystic fibrosis. However, recent developments in diagnosis and treatment of the disease mean that people with cystic fibrosis can now enjoy a greatly improved lifespan and quality of life.
Current treatment strategies focus mainly on reducing the production of mucus, preventing infections and managing the nutritional problems that result from having cystic fibrosis.
Treatments for cystic fibrosis include:
Lung and airway treatment
There are several therapy techniques that can help to physically clear the lungs and airways of the mucus build-up. This is done on a regular basis, usually once a day.
The treatment generally involves a carer or health professional thumping the chest area of the patient in a variety of ways and postures. Breathing exercises are also used, as well as devices that use vibration and air compression to help dislodge and clear mucus from the airways.
Nasal congestion can be cleared with the aid of inhalation, or a gentle flushing of the nasal passages with a salt rinse.
Exercise can help to reduce inflammation, encourage air flow and loosen mucus from the respiratory system. Exercise can also maintain healthy function of the joints and muscles of the chest and back, and can improve breathing.
Medication to treat respiratory problems in cystic fibrosis can be divided into five categories:
- Antibiotics - to help fend off bacterial infections of the lungs and airways;
- Bronchodilators - to widen the airways and help with breathing, such as inhaled salbutamol;
- Anti-inflammatory medication - to fight inflammation and swelling;
- Mucolytics - medication to help break down and thin out the mucus, such as nebulised hypertonic saline or inhaled mannitol, and;
- Gene therapy - a new category of medications is being designed to deal with the root cause of cystic fibrosis, the malfunction of the mutated CFTR gene. The first of these medications, ivacaftor, was recently approved for use. 
Lung transplantation can sometimes be recommended in cases of severe lung disease. However, this transplantation does not cure cystic fibrosis in other affected organs.
Digestive system treatment
People with cystic fibrosis benefit from a carefully planned diet to help them cope with their impaired digestive system. The increased loss of salt from the body means it is important to keep a close eye on hydration and salt levels, especially during exercise.
Regular supplements of enzymes help to replace the body's own digestive enzymes, which cannot otherwise reach the intestines. These help to offset malnutrition and other symptoms associated with cystic fibrosis.
These are given to replace the nutrients that people with cystic fibrosis do not absorb from their diet. They include electrolyte and vitamin supplements.
In some cases of intestinal blockage, surgery may be needed.
Problems with lungs are the main complications associated with cystic fibrosis, causing about 85% of deaths.  The onset of complications occurs over a period of time, as the repeated damage from mucus, inflammation and infections accumulates in the lungs. Some of the complications include:
Digestive system complications
Complications of the digestive system include:
- Pancreatitis - inflammation of the pancreas;
- Rectal prolapse - rectal tissue protruding from the anus as a result of extensive coughing and/or problems passing stools;
- Heartburn, and;
- Distal intestinal obstruction syndrome (DIOS) - a form of bowel obstruction.
As cystic fibrosis progresses over time, it can contribute to several other health problems. These can include:
- Diabetes - this is a common complication of cystic fibrosis. Up to 15% of teenagers and 50% of adults develop the condition; 
- Bone and joint problems, such as arthritis and osteoporosis;
- Infertility - individuals with cystic fibrosis can enjoy a normal sex life, however most men are infertile (in about 98% of cases). Fertility in women is more variable, but it is generally lower than the general population;
- Bowel and urinary incontinence, and;
- Liver damage.
Until recent times, people with cystic fibrosis were not expected to survive beyond their teenage years. Today, advances in treatment have allowed people with cystic fibrosis to live well into adulthood. The current average life expectancy of people with cystic fibrosis is 38 years.
People with cystic fibrosis can expect to lead a relatively normal life if they follow the nutritional, physical and medication routines described above. Their increased susceptibility to infection means they tend to spend more time in hospital, but they can still continue to study, work and enjoy social and romantic relationships.
Living with cystic fibrosis can sometimes be emotionally difficult. People with cystic fibrosis are encouraged to share any emotional issues they may have with family, friends and healthcare professionals. They are at increased risk of developing depression.
There are dedicated cystic fibrosis support groups, like Cystic Fibrosis Australia, who can provide resources, support and connect you with other people living with the condition.
Cystic fibrosis cannot be prevented. As a genetic disease, the only preventative measures are screening for the genetic defect, either before conception or before birth.