A number of brain disorders have been described in other chapters. Possibly the least common brain disorder described in this book, but the one that may provoke the most concern are the brain tumors.
Brain tumors are groups of cells that exhibit uninhibited growth. They may be either benign where they do not spread to other parts of the body or invade surrounding tissue or they may be malignant. A primary malignant brain tumor arises in the brain and will frequently shed cancerous cells to other parts of the central nervous system.
Classification of brain tumors may be by the cells of origination. For example, gliomas represent about half of primary brain tumors and they originate from glial cells that make up the connective tissue of the brain.
Tumors of the brain may be classified by their location. The higher centers of the brain are termed the cerebral hemispheres; the medulla regulates vital functions including respiration, and the midbrain helps to control vision are hearing. An acoustic neuroma arises in the acoustic or auditory nerve. Pituitary tumors develop in the pituitary gland, and a medulloblastoma would arise in the medulla or surrounding tissues.
Although brain tumors are the most common solid tumor in adolescents, the true incidence in adolescence is not well understood. About seventeen thousand Americans develop primary brain tumors each year and ninety percent of these occur in adults. Usually brain tumors are most common in children between ages three and twelve years and adults between fifty-five and sixty-five years.
There is some research that suggests that certain brain tumors are the result of abnormal or missing genes. The gene called Mutated Multiple Advanced Cancers (MMAC1) is defective in the majority of the glioblastoma brain tumors. The Patched 2 gene, that appears to promote tumor growth is found in about half of all medulloblastomas. The genetic abnormalities that are associated with some brain tumors are not usually inherited; rather, they may be acquired from an environmental insult or some other factor. Researchers are trying to determine if certain environmental insults including chemicals, ionizing radiation and viruses, may contribute to the development of brain tumors.
Who is likely to develop a brain tumor?
About fifteen hundred children and younger adolescents are diagnosed with primary brain tumors each year, and half of these are benign. There has been some association between a higher risk for brain tumors and the following conditions:
Five percent of brain tumors are associated with a hereditary disorder. For example, neurofibromatosis, which could be transmitted from parent to child, can cause glioma tumors in the optic nerve pathways.
What are the symptoms of brain tumors?
Adolescents with brain tumors may have a variety of symptoms. Tumors cause symptoms by directly damaging the nerves or brain tissue or by imposing pressure on the brain. Headache is probably the most common symptom. It is usually worse in the morning than the afternoon, and usually in the front of the head. It tends to come and go, not throb and may arouse the teen from sleep. It is not a migraine headache, even though it could be accompanied by visual disturbances including double vision.
Other types of brain tumors may precipitate seizures or changes in mental behavior. These changes include impaired concentration, memory loss, and increased need for sleep. Of course, these symptoms can be seen in other types of disorders.
Problems with specific nerves or functions may be caused by some tumors. For example, tumors of the auditory nerve may cause hearing problems, and tumors around the pituitary gland could cause a problem with a teen’s hormones. The menstrual cycle, for example, could be affected by a pituitary tumor.
How are brain tumors evaluated?
When a teen presents to the clinician with a possible brain tumor, a complete neurological exam is performed. Imaging tests will then be ordered. Magnetic Resonance Imaging or MRI uses a magnetic field, rather than x-rays to provide pictures of the brain from a variety of angles. It is able to give a clear picture of tumors in three planes. Sometimes Computed Tomography or CT is used. This is an x-ray procedure that determines the size and location of most tumors and is helpful in determining swelling and bleeding. A spinal tap is usually performed to determine if tumor cells are present in the spinal fluid. This would be an indication that the cancer has spread.
How are brain tumors treated?
The three traditional modalities to treat brain tumors are surgery, radiation and chemotherapy. Neurosurgeons try to remove as much of the tumor as possible without causing neurological deficits. By reducing the size, the patient’s symptoms may improve and radiation therapy may be more effective. Some tumors may not be operable due to their location. Outside the brain, surgical removal of a tumor may also involve taking out some healthy tissue to ensure the entire tumor has been removed. In the brain, removing healthy tissue may be disastrous to the patient.
Radiation therapy has an important role in the management of malignant as well as benign brain tumors. Since microscopic amounts of tumor tissue may remain after surgery, radiation therapy can be utilized to reduce this tissue.
Chemotherapy is not an effective primary treatment for brain tumors since the blood brain barrier may impede the passage of chemotherapeutic drugs into the brain. In addition, chemotherapy may destroy healthy cells including the stem cells in the bone marrow from which all blood cells develop. Some adolescents who are to receive high dose chemotherapy for a brain tumor may be candidates for a bone marrow transplantation. In this situation, bone marrow, which would otherwise be destroyed by chemotherapy, is removed and frozen. High doses of chemotherapy are administered to the patient, and then the marrow is given back to the patient intravenously.
Teens who survive with brain tumors may be at risk for long-term psychosocial issues. Treatment for brain tumors may cause changes in body image, independence, peer relationships, sexuality and intellectual capabilities. Tumors may cause nerve damage, personality changes and motor problems. Hair may never return completely after radiation therapy. It is exceedingly important that a teen who has been diagnosed with a brain tumor to have access to psychosocial services.
How are brain tumors prevented?
At this time, there is no prevention for brain tumors.
Related topics:
Chronic illness, disabilities, encephalitis, epilepsy, hair loss, head injuries, headaches, hearing loss, meningitis, neurofibromatosis, seizures, self-esteem
