Hersentumor (in het Engels)

Beoordeling 4
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  • 24 mei 2001
  • 35 keer beoordeeld
  • Cijfer 4
  • 35 keer beoordeeld

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Engels
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CHAPTER 1: WHAT IS A BRAIN TUMOR
Brain tumors are tumors that grow in the brain. A tumor is an abnormal growth caused by cells reproducing themselves in an uncontrolled manner.
There are two types of tumors; benign (meaning harmless) and malignant (meaning cancerous). These meanings change, however, when referring to tumors in the brain.
Benign brain tumors:
A benign brain tumor consists of benign (harmless) cells and has distinct boundaries. Surgery alone may cure this type of tumor.
Malignant brain tumors:

A malignant brain tumor is life-threatening. It may be malignant because it consists of cancer cells, or it may be called malignant because of its location. In other words, a brain tumor composed of benign cells--but located in a vital area--is still considered malignant, because they are very dangerous anyway.
A malignant brain tumor made up of cancerous cells may spread or seed (metastasize) to other locations in the brain or spinal cord. It can invade and destroy healthy tissue so it cannot function properly. Malignant tumors grow the way a plant does, with "roots" invading various tissues. Or, they can shed cells that travel to distant parts of the brain. Some cancerous tumors, however, remain localized. Malignant brain tumors seldom metastasize outside the brain and spinal cord. Often, the damage done by brain tumors is due to their size. Because the skull is bone, it cannot expand to make room for even a small mass growing within it. As a result, the tumor presses on and displaces normal brain tissue. This pressure may damage or destroy delicate brain tissue. This pressure causes many of the symptoms of a brain tumor. Sometimes, a tumor may cause blockage of fluid that flows around and through the brain. This blockage can also create increased pressure.
Then it is possible to separate the brain tumors again; there are tumors starting in the brain, which are called primary brain tumors, and there are Metastatic brain tumors, which are tumors consisting out of cancerous cells formed elsewhere in the body and spread to the brain.

CHAPTER 2: WHAT IS THE BRAIN, WHAT DOES IT EXIST OF, AND WHAT EFFECT HAS THE LOCATION ON THE TUMOR
The brain is simply a soft, spongy mass of nerves and supportive tissue. The bas eof the brain is connected to the spinal cord, and the nerves that extend out of the brain and spinal cord into various parts of our body, act together to send information to the brain and send instructions from the brain. The brain itself is divided as well, there are different, parts of the brain responsible for different things, in this chapter the different tasks and places are described.
Cerebrum - This contains the largest part of the brain. It consists out of two halves, the right and left hemispheres. The right hemisphere controls the left part of the body, and the left hemisphere takes care for the right part of the body. The outer part of the cerebrum, called the cerebral cortex, is made up out of grey matter, but the inner part though is white matter. In addition, there are areas of grey matter, called basal ganglia. Grey matter is composed of nerve cells. These cells control brain activity. White matter is composed of myelinated nerve cell axons that carry information between nerve cells in the brain and spinal cord. The hemispheres are divided up in four lobes again, and each lobe is responsible for specific things in the body.

Frontal lobe - Responsible for voluntary muscle movements. The frontal lobe of the dominant hemisphere controls speech and writing. (The dominant hemisphere is the opposite side of the side you use most, left-handed means the right hemisphere is dominant)
Parietal lobe - The parietal lobe receives and interprets sensations, such as pain, temperature, touch, pressure, size, and shape. Other activities of this lobe are hearing, reasoning, and memory.
Temporal lobe- Involved in understanding of sounds and spoken words, further involved as well in emotion and memory.
Occipital lobe – Involved in understanding visual images and the meaning of written words.
Cerebellum - This is the second largest area of the brain, also consisting out of two hemispheres, these are connected by the vermis. The cerebellum, together with the thalamus and cerebrum, controls skilled muscular co-ordination, including walking and speech (words doctors would use for this are gait and articulation)
Pons - The pons co-ordinates the activities of the cerebrum and cerebellum by relaying them and the spinal cord.
Medulla Oblongata - The Medulla Oblongata controls respiration, heart beat and vomiting. It connects the brain with the spinal cord.
Ventricles and choroid plexus - There are four connected ventricles (cavities) in the brain, inside each there are structures called choroid plexus.
Choroid plexus forms spinal fluid, which flows through the ventricles and the subarachnoid space surrounding the brain and spinal cord.
There are two lateral ventricles, one in each cerebral hemisphere. The third ventricle is beneath the corpus callosum and surrounded by the thalamus. The fourth ventricle is between the hemispheres of the cerebellum. It is an expansion of the central canal of the medulla oblongata.
The cerebral aqueduct, called the aqueduct of Sylvius, is a narrow canal connecting the 3rd and 4th ventricles.
Hypothalamus - The hypothalamus makes up part of the wall of the third ventricle and is the base of the optic chiasm. It controls water balance, sleep, temperature, and blood pressure. The hypothalamus co-ordinates patterns of activity and controls emotions. It is also the control centre for the pituitary gland.
Thalamus - The thalamus surrounds the third ventricle. It monitors input from the senses and acts as a relay station for the sensory centre of the cerebrum.
Limbic System - The limbic system, together with the hypothalamus, controls hunger, thirst, emotional reactions, and biological rhythms. In addition, it co-ordinates complex activities requiring a sequence of performance steps.
Brain stem - The brain stem controls basic functions, including blood pressure, heart beat, and respiration. It is the bottom-most portion of the brain, connecting the cerebral hemispheres with the spinal cord. There are several structures part of the brain stem:
- Pons Reticular Formation
- Medulla Oblongata Midbrain
Reticular Formation - The reticular formation is the central core of the brain stem. It controls consciousness, eating, and sleeping patterns, drowsiness, and attention. The reticular formation connects with all parts of the brain and brain stem.
Midbrain - The midbrain is the short portion of the brain stem between the pons and the cerebral hemispheres. The midbrain is a relay centre for sight and hearing.
When a brain tumor enters the brain and starts growing, it presses some other thing away (the part of the brain where the tumor is growing), which makes it impossible for that part of the brain to do its function the way it should do it. It will die or at least injure, depending on which part of the brain it is, the symptoms will differ as well.
The parts of the brain all have their own function, and those parts of the brain bullied by the tumors can’t operate functional. Here will follow some examples of what the effects are when a tumor bothers those parts of the brain:

- Brain Stem Tumors (Midbrain, Pons, Medulla Oblongata)
Tumors of the brain stem can produce a variety of symptoms. The most common symptoms are vomiting, usually just after awakening, and a clumsy, uncoordinated walk (ataxic gait). Muscle weakness on one side of the face causes a one-sided smile or drooping eyelid. Difficulty in swallowing (dysphagia) and difficulty with speech (dysarthria) are also common symptoms. In addition, abnormalities in the functioning of the eye nerves produce "crossed eyes" or decreased vision. Headache, usually just after awakening, may also occur. Head tilt, drowsiness, hearing loss, one-sided muscle weakness (hemiparesis), and personality changes may be present. Symptoms may develop gradually.
- Cerebellopontine Angle Tumors (Usually Acoustic Nerve Tumors)
The earliest symptom is ringing or buzzing in the ear (tinnitus). Less often, dizziness (vertigo) may occur. As the tumor grows, additional symptoms such as deafness, and others similar to those of a brain stem tumor may occur.
- Frontal Lobe Tumors
Common symptoms include one-sided paralysis (hemoplegia), seizures, defective memory, impaired judgement, and personality or mental changes. If the tumor is at the base of the frontal lobe, loss of sense of smell (anosmia), impaired vision, and a swollen optic nerve (papilledema) may occur.
Mental or personality changes and a clumsy, uncoordinated walk (ataxic gait) are common symptoms if the tumor involves both the left and right frontal lobes.
- Parietal Lobe Tumors
Seizures, speech disturbances if the tumor is in the dominant (usually left) hemisphere and loss of ability to write (agraphia) are common symptoms. Spatial disorders, such as difficulty with body orientation in space or recognition of body parts, may also occur.
- Occipital Lobe Tumors
Blindness in one direction (hemianopsia) and seizures are common symptoms.
- Temporal Lobe Tumors
These tumors usually are "silent." They often cause no symptoms other than occasional seizures or language disorders

CHAPTER 3 TREATMENTS
Brain tumors are treated with surgery, radiation therapy, and chemotherapy. Depending on the patient's needs, several methods may be used. The patient may be referred to doctors who specialize in different kinds of treatment and work together as a team. This medical team often includes a neurosurgeon, a medical oncologist, a radiation oncologist, a nurse, a dietician, and a social worker. The patient may also work with a physical therapist, an occupational therapist, and a speech therapist.
Before treatment begins, most patients are given steroids, which are drugs that relieve swelling (edema). They may also be given anticonvulsant medicine to prevent or control seizures. If hydrocephalus is present, the patient may need a shunt to drain the cerebrospinal fluid. A shunt is a long, thin tube placed in a ventricle of the brain and then threaded under the skin to another part of the body, usually the abdomen. It works like a drainpipe: Excess fluid is carried away from the brain and is absorbed in the abdomen. (In some cases, the fluid is drained into the heart.)
Surgery
Surgery is the usual treatment for most brain tumors. To remove a brain tumor, a neurosurgeon makes an opening in the skull. This operation is called a craniotomy.
Whenever possible, the surgeon attempts to remove the entire tumor. However, if the tumor cannot be completely removed without damaging vital brain tissue, the doctor removes as much of the tumor as possible. Partial removal helps to relieve symptoms by reducing pressure on the brain and reduces the amount of tumor to be treated by radiation therapy or chemotherapy.
Some tumors cannot be removed. In such cases, the doctor may do only a biopsy. A small piece of the tumor is removed so that a pathologist can examine it under a microscope to determine the type of cells it contains. This helps the doctor decide which treatment to use.
Sometimes, a biopsy is done with a needle. Doctors use a special headframe (like a halo) and CT scans or MRI to pinpoint the exact location of the tumor. The surgeon makes a small hole in the skull and then guides a needle to the tumor. (Using this technique to do a biopsy or for treatment is called stereotaxis.)
Radiation therapy
Radiation therapy (also called radiotherapy) is the use of high-powered rays to damage cancer cells and stop them from growing. It is often used to destroy tumor tissue that cannot be removed with surgery or to kill cancer cells that may remain after surgery. Radiation therapy is also used when surgery is not possible.
Radiation therapy may be given in two ways.
- External radiation comes from a large machine. Generally, external radiation treatments are given 5 days a week for several weeks. The treatment schedule depends on the type and size of the tumor and the age of the patient. Giving the total dose of radiation over an extended period helps to protect healthy tissue in the area of the tumor.
Radiation can also come from radioactive materials placed directly in the tumor (implant radiation therapy). Depending on the material used, the implant may be left in the brain for a short time or permanently. Implants lose a little radioactivity each day. The patient stays in the hospital for several days while the radiation is most active.
External radiation may be directed just to the tumor and the tissue close to it or, less often, to the entire brain. (Sometimes the radiation is also directed to the spinal cord.) When the whole brain is treated, the patient often receives an extra dose of radiation to the area of the tumor. This boost can come from external radiation or from an implant.
- Stereotactic radiosurgery is another way to treat brain tumors. Doctors use the techniques described earlier to pinpoint the exact location of the tumor. Treatment is given in just one session; high-energy rays are aimed at the tumor from many angles. In this way, a high dose of radiation reaches the tumor without damaging other brain tissue. (This use of radiation therapy is sometimes called the gamma knife.)

Chemotherapy
Chemotherapy is the use of drugs to kill cancer cells. The doctor may use just one drug or a combination, usually giving the drugs by mouth or by injection into a blood vessel or muscle. Intrathecal chemotherapy involves injecting the drugs into the cerebrospinal fluid.
Chemotherapy is usually given in cycles: a treatment period followed by a recovery period, then another treatment period, and so on. Patients often do not need to stay in the hospital for treatment. Most drugs can be given in the doctor's office or the outpatient clinic of a hospital. However, depending on the drugs used, the way they are given, and the patient's general health, a short hospital stay may be necessary.

Conclusion
The information I’ve gained is only the base of what there is for research going on right now around the world; there are people trying to find ways, safer ways, to treat the brain tumors, because it isn’t safe to remove or partly remove those things, at least not yet. This is a topic with which this project could continue, further this project could have been extended with the description of all kinds of different tumors, or with facts and figures.
I can give some figures anyways, some interesting, but there are many more!!!

- Within the next 365 days, over 100.000 people in the USA will be diagnosed with a primary or metastatic brain tumor, and the incidence is on th rice!!!
- Brain tumors are the second largest leading cause of cancer death in children up to 15 and in young adults up to age 34!!!
- Aproximately 44% of all primary tumors are benign!!!
- Currently, brain tumors cannot be prevented, because their cause is still unknown!!!

There are many more of those figures and I could easily have continued for 5 – 10 more of these facts.

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