Download non-infectious diseases

NON-INFECTIOUS DISEASES
Non-infectious diseases are not often caused by an outside agent. The causes of non-infectious diseases
are frequently unknown. For example, some cancers can be linked with environmental factors like
exposure to radiation, but the cause of many remains a mystery.
Genetic diseases
Inside every cell is a nucleus, which is the control centre for the cell. The nucleus contains
chromosomes which consist of DNA(deoxyribonucleic acid) and carry genes – the code for every
characteristic of the organism. For example, if you have brown eyes it is because your chromosomes
carry the gene for brown eyes.
Genetic diseases are caused by abnormalities in one or more genes – this means that the code contained
on the chromosomes is faulty. These genetic abnormalities are also called mutations. Gene
abnormalities are sometimes inherited, but not always.
Not infrequently, an inheritable disorder like haemophilia may suddenly show up in a family that has
no previous history of the disease. This is caused by a new gene mutation. The cause of gene mutation
is often unknown but some things that can cause this are radiation, drugs and other chemicals, and
some viruses. Once a new mutation has resulted in an inheritable disorder, this disorder will continue to
be passed on through future generations.
An example of an inherited genetic disease is haemophilia. People with haemophilia lack an important
clotting factor in their blood. One non-inherited genetic diseases is Turner’s syndrome.This causes
webbing of the neck, infertility, short stature and subnormal intelligence. Down’s Syndrome is not
usually inherited, however some women have anomolies in their genes that could increase their risk of
having a child affected with the disorder. The chance of a woman having a child with Down’s
syndrome increases with age. At 25 the risk is 1 in 1250, but by the time a woman is 45 the chance has
risen to 1 in 30.
Diseases caused by diet
Many diseases can be directly linked to the way we treat our bodies. Some people in developing
countries do not have the food choices we have and are prone to malnutrition due to their limited diets.
Vitamin and mineral deficiencies can easily cause death if not corrected. Another problem can be too
much or too little food. Obesity is a widespread problem in Australia. Excessive weight can place a
strain on all body systems. The effects of obesity include high blood pressure, joint and blood vessel
problems. Obese people are also more likely to develop diabetes.
Anorexia nervosa can result in weight loss severe enough to cause massive organ failure and death.
Bulimia nervosa is a related disorder characterised by a bingeing and purging cycle. The imbalance of
electrolytes that results from this cycle can sometimes cause heart failure. Electrolytes are substances
that conduct electric current. Amongst other things, electrolytes are responsible for maintaining a
regular heartbeat.
Diabetes mellitus is a disorder in which glucose, the energy source for our bodies, is not used properly
due to a lack of a substance called insulin. Diabetes seems to have some sort of genetic component but
there is no defined pattern of inheritance. There are two types: juvenile onset (Type I) and mature onset
(Type II). Being overweight is a common factor in mature onset cases. If the insulin deficiency is
serious, regular injections are needed throughout the patient’s life. If the condition is less serious, it can
often be controlled through tablets or diet. An uncorrected lack of insulin can result in a diabetic coma
and death.
Diseases of the heart and blood vessels
In Australia, heart disease is the leading cause of death in males over 35 and females over 60. Some
problems that we think of as heart disease are in fact diseases of the blood vessels, rather than the heart
itself.
Thrombosis is a disease that causes a large, solid mass (a thrombus) to form on the inside wall of a
blood vessel. Sometimes these large masses can detach from the wall of the blood vessel and end up
blocking major arteries, causing death. The blockage of a blood vessel is called an embolism. The
embolism can result from a thrombus, gas, fat, tumour cells, or some type of foreign body.
Hypertension is the name given to persistent high blood pressure. It is more common in women than
men, but it produces much more serious effects in men. It can cause arteriosclerosis, or hardening of
the arteries, and coronary heart disease. The worst type of arteriosclerosis is called atherosclerosis. It is
characterised by fatty deposits within arteries. These deposits can eventually cause arteries to become
blocked. Atherosclerosis can occur in any part of the body, not just the heart. It can be inherited, but is
also strongly linked to environmental factors like smoking and diet.
Varicose veins are more likely to occur in women than men, and are usually inherited. If you are a
woman and one of your parents has varicose veins, there is a very high chance that you will develop
this condition. They are related to irregularities in vein walls and weakness in the valves of veins which
stop blood flowing back to the heart normally. Varicose veins are usually seen in the veins of the legs,
which have to fight gravity to get blood back to the heart. Unsightly, bulging veins develop where
blood is trapped.
Coronary heart disease refers to anything that reduces blood flow to the heart and is usually caused
by arteriosclerosis. It can cause milder attacks of chest pain, called angina, or a serious heart
disruption, called a heart attack. About 25% of people with coronary heart disease die suddenly from
a heart attack.
Other diseases, including diabetes, can cause weakening of the heart.
Curious fact: Healthy Hearts
Want to know one easy way to help keep your heart healthy? Floss! That’s right. Gum disease can
result in your mouth having an extremely high concentration of bacteria. This bacteria can end up in
your bloodstream and cause damage to your heart.
Cancer
New cells grow through a process of cell division. Cancer arises when cell division occurs
uncontrollably. Changes in cells can trigger off this uncontrollable division. Cell division is a carefully
controlled process and even tiny changes within cells can be enough to disturb the process and produce
cancer.
A tumour is any abnormal growth in the body. A benign growth is one in which cells are not rapidly
dividing. A wart is an example of a benign tumour. A malignant growth is one in which uncontrollable
growth is occurring – this is cancer. To determine if a tumour is malignant or benign, a biopsy is
carried out. A tissue sample is taken from the tumour and examined under a microscope.
Cancer can occur anywhere in the body. The skin is the most common site for cancers in men, while
the breasts are the most common site for cancers in women. Factors that can lead to cancer are cigarette
smoking (lung cancer), exposure to the sun (skin cancer), poor diet (bowel cancer), and exposure to
certain chemicals called carcinogens.
Cancer can be caused by environmental factors or through a genetic predisposition. Normally several
factors have to come together before a malignant growth will occur. If a malignant growth has
occurred, it is important to treat it before metastasis occurs. Metastasis is the process by which
cancerous cells find their way into the circulatory or lymph systems and travel to other parts of the
body. Secondary cancer sites (called metastases) develop and the disease becomes very difficult to
treat.
Leukhaemia is a type of cancer of the bone marrow and tissues that produce blood cells. The first
symptoms are usually fatigue, unexplained bruising and anaemia, due to the lack of red blood cells. An
abnormal number of white blood cells appear. Like most cancers, there is no known cure, but many
treatment options are available.
Common treatments for cancer are surgery, radiotherapy (using radiation to kill localised growths) and
chemotherapy (using chemicals). These treatments can have serious side-effects. The best chance for
surviving cancer is to catch it early while it is still small and metastasis has not occurred.
Alcohol and smoking
Two of the most widely used and abused drugs in modern society are the legalised drugs – alcohol and
nicotine. Because they are legal, their use is much more widespread, open and accepted than illegal
substances like heroin and amphetamines. However, their results can be just as devastating, both to the
user and to those around them.
Alcohol directly accounts for about 7% of male deaths in Australia and around 4% of all female deaths.
The abuse of alcohol results in the disease we call alcoholism. A person is an alcoholic if their drinking
is compulsive. At this stage, their dependence is sometimes physical as well as psychological.
Alcohol anaesthesises the central nervous system, slowing it down. Alcohol also stimulates urine
production, so body cells become dehydrated. It temporarily puts part of the liver out of action. Chronic
abuse of alcohol causes many ill-effects. It causes digestive problems because alcohol destroys the
lining of the stomach. Malnutrition and vitamin deficiencies can occur because diet is neglected.
Alcohol provides a lot of kilojoules but no nutrients. The liver is slowly destroyed by cirrhosis – this is
where cells die and are replaced by fibrous tissue. The heart can be damaged, brain cells are destroyed
and the central nervous system slowly deteriorates.
The initial effects of alcohol are a sense of warmth, well-being and loss of inhibitions. These effects are
particularly attractive to people with low self-esteem who don’t cope well in social situations. With a
little more alcohol, reactions become slower and senses become dulled. This is why it is very
dangerous to drive even after relatively small amounts of alcohol.
If more alcohol is ingested, intoxication occurs. The person will be staggering, nauseous, possibly
vomiting, and will have difficulty speaking. If the blood alcohol level gets to 0.40%, it is likely the
person will fall into a coma. Above levels of 0.60%, the alcohol causes death through heart and
respiratory failure. This rarely happens because unconsciousness and vomiting usually force the person
to stop drinking.
Although small amounts of alcohol have been shown to be helpful in preventing heart disease, it should
be noted that this only applies for the over 40’s and to amounts of less than two standard drinks. Any
more than that has a harmful effect. Even small amounts of alcohol can make the symptoms of mood
disorders like depression and anxiety much worse. Binge-drinking is a particularly harmful practice.
Women are not able to metabolise as much alcohol as men and so ill-effects occur with smaller
amounts. It is recommended that adult males have no more than 28 standard drinks per week and adult
females have no more than 14 standard drinks per week. A standard drink is a shot of spirits, a glass of
wine or a bottle of beer. Everyone should have at least two alcohol-free days a week.
The harmful effects of smoking have been well-documented and yet every year more and more young
people take up the habit. More young women than men are smokers, one common reason being that it
is an appetite suppressant. The sight of many models and actors lighting up can give smoking a
glamorous image that is a long way from the reality of bad breath and a multitude of health problems.
Once the habit is formed, it is not an easy one to give up. Withdrawal symptoms include intense
craving, anxiety, sweating, depression, sleep problems and difficulty concentrating. It often takes many
attempts before people are able to kick the habit for good.
Before you think about lighting up, have a think about these statistics. Smokers are more likely to have
accidents than non-smokers due to their reflex actions being slowed down following a cigarette. The
constriction of blood vessels means that smokers’ brains don’t work as well as non-smokers’ brains.
Smokers are twice as likely to die before middle-age than non-smokers. Smoking increases the risk of
developing many diseases, not just lung cancer. Pregnant women who smoke are more likely to have
low birth weight babies with health problems and reduced intelligence.
Environmental Hazards
Environmental hazards that can cause diseases include radiation and heavy metals. Diseases caused by
environmental hazards are usually avoidable but some people are being constantly exposed to potential
hazards without being aware of them.
Radiation can come from natural sources, like the sun, or can be generated from artificial sources like
X-rays and nuclear explosions. Radiation most commonly causes mutations in cells, producing various
cancers.
The heavy metals include mercury, thallium, lead and bismuth. Mercury and lead poisoning are more
common throughout history because these metals were used for a variety of purposes before the illeffects were known.
Lead poisoning has been associated with exhaust from cars and high levels of lead in soil due to flaking
of paint. These days lead is rarely used in paint but many older paints had a high lead content. Chronic
lead poisoning has many ill-effects including foetal deformities in pregnant women and mental
impairment in children.