|
Cystic Fibrosis
The following text deals with various aspects of cystic fibrosis.
A large part of it was taken from the Quebec
Cystic Fibrosis Association’s Web site.
Symptoms
Causes
Diagnostic
Treatments
Introduction
Cystic fibrosis is a hereditary disease that affects the respiratory
and digestive systems, in terms of poor mucous gland function.
In Canada, it is estimated that 3,000 people have this disease. Although
research has made enormous strides, no cure or means to control
cystic fibrosis has yet been found.
Cystic fibrosis affects the mucous glands and as a result, digestion and lung function.
Normally, mucus is fluid and helps keep the lungs and airways
clear by helping to eliminate germs and dust particles. In CF
patients, mucus is thick and sticky and obstructs the bronchioles,
making breathing difficult. Air is trapped in some bronchioles,
and mucus blocks the lungs; bacteria accumulate and proliferate in the
obstructed bronchioles and cause infections.
Mucus also obstructs the fine ducts of the pancreas, an
organ located near the intestines, below the stomach. The pancreas
secretes enzymes that normally go to the small intestine to aid digestion.
When the orifices of the pancreas are blocked by mucus, the enzymes
cannot reach the intestine, causing food to be only partially
digested and therefore to lose some of its nutritional value.
Sweat glands are also affected. The sweat of a person with
CF usually has a high salt content. This does not usually result
in serious problems; however, if the weather is
hot or if the person has a high fever or engages in
strenuous physical activity, the body will lose a large amount of salt.
Frequent antibiotic treatment may become necessary
for individuals with cystic fibrosis in order to control lung infections.
Most people with CF need to take enzymes
daily to improve food absorption and caloric intake.
Cystic fibrosis symptoms appear very early in life.
For some, symptoms are first noticed in the lungs, and for others,
in the digestive system. Nevertheless, most children
and adults suffering from CF produce both symptoms.
Symptoms
Usually, parents provide doctors with the first clue
that their child has cystic fibrosis. The salty taste of the
child’s skin is quickly noticed when kissed.
Other symptoms include a persistent cough similar
to whooping cough, wheezy breathing that can be mistaken for asthma,
repeated lung infections, such as bronchitis and pneumonia, a slowdown in
growth, poor weight gain despite a big appetite, and frequent, large, foul-smelling bowel movements. The cough can be so persistent that
it can disturb the child’s sleep and food intake, and may even induce vomiting.
A distended abdomen can also be a symptom of cystic
fibrosis. However, if it is the only symptom, it is not likely to be due to
the disease, for a round belly is common in little children. Sometimes,
large bowel movements can cause slackening of the
rectum (prolapsus of rectum). There is occasional abdominal
pain, which is the result of accumulated gas caused by poor digestion.
Cystic fibrosis is not always detected in children; sometimes,
the symptoms are not very obvious. Chronic diarrhea, breathing
problems and other CF symptoms can be
attributed to other illnesses as well.
A symptom of cystic fibrosis that is easy to identify is meconium
ileus, an intestinal occlusion that occurs when the intestines are
blocked by secretions that have the consistency of putty. This causes
abdominal bloating, vomiting and severe constipation. In many cases,
medical therapy is sufficient, but complicated cases require surgery.
Causes
Cystic fibrosis appears in children who inherit two CF genes,
one from each parent. A parent whose cells contain only one
gene cannot have cystic fibrosis. However, if two persons carrying this gene have
children, one or more of their children can inherit
both genes and be born with cystic fibrosis.
In this case, for every birth, there is a 25% chance
that the child will have cystic fibrosis, a 50% chance that the child will
only be a carrier of the gene, and a 25% chance that the child will neither
have cystic fibrosis nor carry the CF gene.
In Canada, cystic fibrosis affects one newborn in 2,500.
Geneticists estimate that one in 25 Canadians carries the CF gene.
Generally, parents of a child with cystic fibrosis do not have
the disease. Often, they have no idea that they are carriers
and cannot understand how they could have passed it on to their baby.
In August 1989, Canadian researchers discovered the healthy
gene that causes cystic fibrosis when it is mutant. When the
child inherits this defective gene from each parent, certain cells in his or
her body produce a protein that does not function normally. Researchers
are currently trying to define the exact role of this protein.
The one thing they do know is that it hinders the transport
of salts and fluids through the membranes of the affected cells.
This produces symptoms characteristic of cystic fibrosis, i.e., the accumulation
of thick, dry mucus in the lungs and the obstruction of the pancreatic ducts.
Cystic fibrosis is a hereditary disease that has nothing to do
with the environment, the child’s position in the family, the parents’
age or the mother’s diet during pregnancy. It is not contagious and cannot
be transmitted from one child to another.
Diagnostic
The symptoms of cystic fibrosis can be misleading. As
mentioned, the cough can be mistaken for whooping cough, and the
wheezy breathing for asthma. When a child has pneumonia or bronchitis, cystic
fibrosis is still not seen as the main cause of the illness. Also, many everyday
digestive problems are similar to the digestive symptoms of cystic fibrosis.
When a doctor suspects that a child has cystic fibrosis, special
tests are performed. A “sweat test” is often done, for which an area
of the skin is stimulated with either heat or medication. If the salt content of
the sweat is above normal, cystic fibrosis will be considered as a diagnosis.
A test to detect enzymes in the intestines might also be carried out.
The doctor will also inquire about the child’s digestive
problems, breathing difficulties, infections and poor weight gain.
Often, a chest X-ray will be taken to determine any changes in the lungs.
By getting a complete picture, the doctor will arrive at a diagnosis;
genetic testing of a blood sample will confirm it.
There is still no cure for cystic fibrosis, but effective treatments
are available. Today, more and more young people are reaching
adulthood without too much damage to their lungs, and even better treatment
methods are promised thanks to the discovery of the CF gene. For the first
time, researchers can establish links between the cause
of the disease and its signs and symptoms.
Lung treatments
Treatment of cystic fibrosis is primarily geared to lung
problems, since the disease as such and its death rate are chiefly attributed
to the infection and poor functioning of the lungs. Lung treatments are
designed to loosen and eliminate the mucus that obstructs the airways
in order to improve lung function. There are many different
methods for achieving this.
Frequent antibiotic treatments help fight and prevent lung infections.
Special aerosol solutions are used to dislodge
and thin out the mucus in the lungs.
Postural drainage is a form of physiotherapy that helps
free the airways. The individual assumes various positions depending
on the area that needs draining so that clapping can be performed on the
lobes of the lungs. This method often dislodges large amounts of mucus.
Other drainage techniques, for instance “huffing” and auto-drainage, do not require another person, thus allowing
the patient to be more independent.
In very severe cases, the lungs are so badly damaged as a result
that a transplant is the only solution.
Gastrointestinal treatments
Gastrointestinal problems caused by cystic fibrosis occur in about 85%
of cases in the form of poor digestion and malabsorption of fats,
proteins and sugars. Before treatment, a person with CF could eat twice
the amount of food consumed by the average person. People with CF usually
need to take a special pancreatic enzyme supplement to help digestion.
They must follow a special high-calorie high-protein diet, and complement
their food intake with vitamin supplements containing vitamin
E and sometimes vitamin K.
Pancreatic enzymes taken orally offset most of the insufficiencies
caused by the disease. They help the body assimilate nutritional
values, and reduce the amount and volume of stools,
accumulated gas, abdominal pain and distension.
Moreover, people with CF are compelled to add salt to their diets
in order to replace the large amounts lost in their perspiration.
|
