Tumors of the Central Nervous System

18 May

Tumors of the Central Nervous System

In the brain and spinal cord, even benign (noncancerous) tumors can be debili- tating or life-threatening. Because the brain and the spinal cord are enclosed within bony structures, there is no room for tissue expansion. Any abnormal growth or swelling puts pressure on delicate tissues and can cause damage and impair function. Benign tumors growing next to critical nerves, brain structures, or blood vessels can compress them and cause problems. Tumors deep in the

brain or surrounding tissue can be difficult or even impossible to remove surgi- cally. Cancerous tumors can damage tissue and impair function. They may spread to the brain from other parts of the body or originate in the brain or spinal cord.

Except for tumors that have spread from other parts of the body, the cause of brain and spinal cord tumors is unknown. Brain tumors can develop at any age. Spinal cord tumors are less common and are most likely to develop in young and middle-aged adults. Some genetic disorders, such as neurofibromatosis (in which many soft tumors grow from nerves in the skin) and tuberous sclerosis (a disorder causing an acnelike skin condition, mental retardation, and epilepsy), also can cause benign tumors to grow throughout the central nervous system.

Tumors of the central nervous system are named for the type of cell or tissue from which they grow. The most common types of tumors in adults include the following:

•  Chordoma. This slow-growing tumor, which usually appears between ages 20 and 40, develops from tissue in the upper spinal cord.

•  Glioma. This type of tumor grows from the glial cells in the brain. Gliomas account for about half of all brain tumors and about a fifth of all spinal cord tumors. Gliomas are categorized according to the type of glial cells from which they arise: astrocytoma (from astrocytes), oligodendroglioma (from oligodendroglia cells), ganglioneuroma (from glial cells and immature neu- rons), and mixed glioma (usually from astrocytes and other glial cells).

•  Meningioma. Meningiomas develop from the meninges (the thin membranes that cover the brain and spinal cord). Meningiomas affect people of all ages but are most common among those in their 40s. Meningiomas grow slowly and rarely spread. Most are noncancerous. Small meningiomas may not cause any symptoms and may be detected by chance during a brain scan performed for another reason.

•  Pineal tumor. Pineal tumors grow in the pineal gland, a small structure deep within the brain, and account for about 1 percent of brain tumors.

•  Pituitary adenoma. The pituitary gland is an endocrine gland in the brain that releases hormones that help control the function of other endocrine glands and influence growth, metabolism, and maturation. Pituitary adenomas are non- cancerous tumors that account for about 10 percent of brain tumors. If a pitu- itary adenoma grows, it can press on the optic nerves and impair side vision.

•  Schwannoma. This type of noncancerous tumor arises from Schwann cells (cells that form a protective sheath around each neuron). One of the more common forms of schwannoma (an acoustic neuroma) affects the major nerve in the brain that is responsible for balance and hearing.

Tumors in the spinal cord are also named according to their location. For example, extradural tumors develop between the vertebrae and the dura (the tough membrane that protects the spinal cord). Tumors within the dura are either extramedullary (outside the spinal cord) or intramedullary (inside the spinal cord).

Brain tumors often do not cause symptoms until they have grown large enough to press on tissue, nerves, and blood vessels and affect brain function. When this occurs, a brain tumor can interfere with a specific sense, learned skill, or bodily function.

Warning Signs of a Brain Tumor
The symptoms described below may indicate a brain tumor or another neurological disorder. If you experience any of these symptoms, see your doctor as soon as possible.

•   Seizure. Talk to your doctor immediately if you experience a seizure for the first time.

•   Loss of movement or sensation. Gradual loss of movement or sensation in part of your body can indicate a growing brain tumor.

•   Unsteadiness. Problems with balance, especially if accompanied by a headache, may be caused by certain brain tumors. Loss of balance should always be checked by your doctor.

•   Visual changes. Partial, temporary, or gradual loss of vision—or double vision that occurs along with a headache—should never be ignored. Tell your doctor as soon as possible if you experience any changes in your vision.

•   Hearing loss. Loss of hearing, especially in young to middle-aged adults, can result from certain brain tumors. Hearing loss due to a brain tumor is sometimes (but not always) accompanied by dizziness.

•   Difficulty speaking. Gradual changes in your ability to speak or to use speech cor- rectly (such as a persistent inability to recall words) should never be ignored. Tell your doctor about even minor changes in your ability to communicate.

•   Behavior changes. Gradual—sometimes barely noticeable at first—changes in behav- ior and emotional stability can indicate a brain tumor. Memory loss, inability to con- centrate, confusion, depression, apathy, and mood swings are sometimes symptoms of a brain tumor.

•   Headache. Certain types of headaches are more likely to be caused by a brain tumor: a constant headache that is worse in the morning and eases slightly as the day goes on; a persistent headache that is accompanied by nausea or vomiting; or a headache that is accompanied by double vision, weakness, or numbness. If you experience any of these types of headaches, see your doctor as soon as possible.

Common symptoms of brain tumors include headaches and numbness or weakness in the arms and legs. The headaches tend to become more severe and

last longer as the tumor grows, and they may be accompanied by nausea and vomiting. If the tumor disturbs the normal flow of electrical signals through the brain, seizures can occur. Pressure on certain nerves can lead to vision or hearing problems. Tumors that arise in the cerebrum, especially toward the front of the brain, can alter normal behavior, personality, memory, language, and learning skills. Tumors located toward the base of the brain can lead to weakness or paral- ysis (partial or complete loss of movement), lack of coordination, or difficulty walking.

A tumor on or near the spinal cord can disrupt the flow of sensory information (including pain) to the brain, or movement commands from the brain to the body. Pain caused by a spinal cord tumor may feel like it is coming from elsewhere in the body. Such pain is usually constant, sometimes severe, and often described as burning or aching. Tumor-related changes in sensation include numbness and decreased sensitivity to temperature. Because all muscles are controlled by nerves, tumors in the spinal cord can cause weakness, spasticity (stiffness and restriction of movement), paralysis, difficulty walking, or loss of bladder or bowel control.

Tests to diagnose a tumor in the brain or spinal cord include computed tomography (CT) scanning and magnetic resonance imaging (MRI; see “Diag- nostic Procedures,” page 342). You may also have cerebral angiography (see “Diagnostic Procedures,” page 342)—an examination of the arteries deep inside the brain to assess the tumor’s type and determine its exact position. Another possible test is an electroencephalogram (EEG), in which electrodes are attached to your scalp to monitor the electrical activity in your brain and help determine if the tumor is causing seizures or otherwise affecting brain function.

Specialized surgical techniques may be used to remove the tumor. Micro- surgery uses a high-power microscope that allows the surgeon to view and access delicate brain tissue. Laser surgery uses powerful, concentrated beams of light to destroy the tumor. Ultrasonic aspiration uses high-frequency sound waves to break up the tumor and an aspirator to vacuum up the pieces. If a tumor cannot be removed and the flow of cerebrospinal fluid inside the brain or skull is blocked, a flexible tube called a shunt will be inserted to reroute and drain the fluid, relieving pressure on the brain.

If a tumor is malignant (cancerous) and cannot be removed completely, radia- tion therapy probably will be used to destroy tumor cells and shrink the tumor. Because radiation therapy destroys only dividing cells, it is particularly useful for treating brain tumors. Doctors use CT scanning and MRI to help focus treat- ment on the tumor and prevent radiation damage to healthy brain tissue.

Chemotherapy (treatment with powerful anticancer drugs) is used to shrink or destroy tumors. Other medications may also be used to relieve problems associ- ated with the tumor. For example, corticosteroids are often prescribed to control the swelling in the brain or spinal cord that can result from a tumor.

Disorders of Brain Function

The underlying causes of certain neurological disorders such as Alzheimer’s disease are not yet known. However, much is known about other neurological disorders—such as Parkinson’s disease, multiple sclerosis, and migraines— although they are not yet fully understood. Research is ongoing to understand these disorders better and to develop effective treatments.

Alzheimer’s Disease

Alzheimer’s disease is a progressive disease in which brain cells degenerate and die, causing memory loss, confusion, loss of intellectual abilities (including thinking, reasoning, judgment, and memory), physical deterioration, and even- tually death. It can also cause significant changes in mood, personality, and behavior. Alzheimer’s disease is the most common form of irreversible dementia (progressive deterioration of mental functioning). The disease usually occurs after age 65, and progresses over a course of about 8 to 10 years. However, it can take as few as 2 or as many as 20 years.

The cause of Alzheimer’s disease is unknown. Most people who develop Alzheimer’s disease have no fam- ily history of it. Women are affected more often than men, but this may be related to the fact that women generally live longer and the disease occurs later in life. Alzheimer’s disease is not a normal part of aging.

Symptoms of Alzheimer’s disease, which vary from person to person, appear gradually and worsen over time. Initial symptoms—such as inability to concen- trate, forgetfulness, anxiety, and depression—often go unnoticed or may be mistakenly attributed to normal aging. Memory problems eventually worsen, and the person also experiences impaired intellectual skills. He or she becomes apathetic and withdrawn. In later stages of the disease the person becomes severely con- fused and disoriented and also may become irritable, fearful, suspicious, delusional, agitated, and even vio-lent. Eventually the person will be unable to perform daily activities (such as bathing, dressing, eating, and using the toilet) and will need total care.

Diagnosis of Alzheimer’s disease is based on symp- toms (as described by the person or his or her family members) and tests that evaluate various aspects of mental functioning (such as short-term memory). To make a diagnosis of Alzheimer’s disease, the doctor

needs to rule out other possible causes of the person’s symptoms, such as depres- sion (see page 345), kidney failure (see page 291), liver disease, thyroid disor- ders, excessive alcohol intake, side effects of medication, drug interactions, fatigue, poor diet, vision problems, and hearing problems. Parkinson’s disease (see page 337), stroke (see page 323), and other neurological disorders, such as meningitis (see page 341) or encephalitis (see page 341), also can cause similar symptoms. Computed tomography (CT) scanning and magnetic resonance imag- ing (MRI; see “Diagnostic Procedures,” page 342) are not performed to diag- nose Alzheimer’s disease but often are used to rule out other possible causes of dementia, such as a brain tumor (see page 326) or a stroke.

Although there is no cure for Alzheimer’s disease, some people in the early to middle stages of the disease may benefit from medications (such as donepezil or tacrine) that help improve memory and manage some of the behavior problems caused by the disease. Other medications to treat or cure Alzheimer’s disease are currently under investigation.

Stimulate Your Mind

Just as exercise strengthens your muscles, neurological research shows that “exercising” your brain may help keep it strong as you age.Engaging in intellectually stimulating activities such as reading, doing crossword puzzles, and learning new things increases the number of connections between the cells in your brain.Doctors now think that these extra connections may provide a buffer against the destructive  effects of Alzheimer’s disease and, in some cases, postpone the onset of symptoms.

Caring  for  a  Person Who  Has Alzheimer’s  Disease Caregiving  can  be demanding, stressful, and exhausting. If you are caring for a loved one who has Alzheimer’s disease, learn all you can about the disease so you can be adequately prepared to deal with this challenging situation. Here are some useful recom- mendations for caregivers:

•  Watch for warning signs of Alzheimer’s disease (see next page) such as for- getfulness, confusion, or withdrawal. Some symptoms may be due to another underlying disease or condition—such as depression (see page 345)—that can be treated and cured.

•  Gather useful information (such as educational materials and referrals to sup- port groups) from reliable sources such as your doctor, your local library, your local hospital, and your local chapter of the Alzheimer’s Association.

•  Make all necessary legal and financial arrangements (including advance directives, durable power of attorney, and payment of healthcare costs) as soon as possible. This will help prevent potential legal and financial problems in the future. Contact a lawyer for additional information and assistance.

•  Take all necessary precautions to protect your loved one from potential dan- gers such as falls, burns, poisoning, and wandering away from home. Taking steps such as locking away hazardous objects and materials (including med- ications, cleaning fluids, matches, lighters, and firearms), installing special locks on doors and windows, and placing night-lights along the route from the bedroom to the bathroom and in the bathroom itself can help prevent seri- ous injuries. The Alzheimer’s Association offers a nationwide program called Safe Return that registers people with memory problems and provides them

with special identification. The program maintains a 24-hour, toll-free number to call when a registered person is either lost or found. Contact your doctor or the Alzheimer’s Association for additional information.

The Warning Signs of Alzheimer’s Disease

The  Alzheimer’s  Association  has  developed the following checklist of common symptoms to help you recognize the warning signs of Alzheimer’s disease. (Some of these symptoms also may apply to other forms of dementia.) If you know someone who has several of these symptoms, he or she should see a physician for a complete examination.

•   Recent memory loss that affects job skills. It is normal to occasionally forget assignments, colleagues’ names, or business associates’ telephone numbers, then remember them later. People who have dementia, such as Alzheimer’s disease, may forget things more often and not remember them later.

•   Difficulty performing familiar tasks. Busy peo- ple can be so distracted from time to time that they may leave the carrots on the stove and only remember to serve them at the end of the meal. People with Alzheimer’s disease could prepare a meal and not only forget to serve it, but also forget they prepared it.

•   Problems with language. Everyone has trouble finding the right word sometimes, but a person with Alzheimer’s  disease may forget simple words or substitute inappropriate words, mak- ing what he or she says incomprehensible.

•   Disorientation of time and place. It is normal to forget the day of the week or your destina- tion for a moment. But people with Alz- heimer’s disease can become lost on their own street, not knowing where they are, how they got there, or how to get back home.

•   Poor or decreased judgment. People can be- come so immersed in an activity that they for-

get  for  a moment  about  the  child  they  are watching. People with Alzheimer’s disease could  forget  entirely  about  the  child  under their care. They may also dress inappropri- ately—for example, wearing an overcoat on a hot day or wearing several shirts or blouses at once.

•   Problems with abstract thinking. Balancing a checkbook may be difficult for anyone when the task is more complicated than usual. A per- son with Alzheimer’s disease could forget completely  what the numbers  are and what needs to be done with them.

•   Misplacing  things. Anyone can temporarily misplace a wallet or keys. A person with Alz- heimer’s disease may put things in inappropri- ate places—for example, an iron in the freezer or a wristwatch in the sugar bowl.

Changes in mood or behavior. Everyone becomes sad or moody from time to time. A person with Alzheimer’s  disease can exhibit rapid mood swings—from calm to tears to anger—for no apparent reason.

•   Changes in personality. People’s personalities ordinarily change somewhat with age. But a person with Alzheimer’s  disease can change drastically, becoming extremely confused, sus- picious, or fearful.

•   Loss of initiative. It is normal to get bored with housework, a job, or social obligations from time to time but most people soon regain their initiative. A person with Alzheimer’s disease, however, may become very passive for long periods of time and require cues and prompt- ing to become involved.

•  Seek help and support from others. Do not try to do everything yourself. Keep an updated list of things that need to be done, and ask reliable family members or friends for help whenever you need it. Contact your doctor, local hospitals, and volunteer, community, and health organizations for information and refer- rals. Join a support group to share information and experiences with others in a similar situation. Consider hiring a professional caregiver through a licensed home health agency.

•  Be realistic about the inevitable outcome of the disease. Prepare yourself to deal with the loss of your loved one. Talking things over with a close friend or relative or with members of a support group will help you come to terms with your grief.

•  Be prepared to make informed decisions about long-term care. A person with late-stage Alzheimer’s disease needs total care. As soon as you learn that your loved one has Alzheimer’s disease, begin gathering information about long- term-care facilities in your area so you will be able to make an informed deci- sion when necessary.

•  Take care of yourself. Take regularly scheduled breaks; eat a nutritious, well- balanced diet (see page 4); exercise regularly (see page 11); do not smoke (see page 107); and get plenty of sleep. Limit your intake of caffeine and alcohol, and use relaxation techniques (see page 119) such as meditation and deep- breathing exercises to help relieve stress.

Contact the Alzheimer’s Association (800-272-3900) for additional informa- tion and advice on caring for a person who has Alzheimer’s disease.

Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS), also called Lou Gehrig’s disease, is a progressive motor neuron disease that has no known cause. In ALS, the motor neurons (nerve cells in the brain and spinal cord that control muscular activity) gradually degenerate, causing the muscles to weaken and waste away, eventually leading to paralysis. ALS occurs during middle age, and men are more likely to develop the disease than women.

Symptoms of ALS include tripping and falling, weakness in the hands and arms, and twitching and cramping of the muscles. As the disease progresses, it can cause difficulty speaking, swallowing, and breathing. In the final stages, although the person is aware and his or her intellect is unimpaired, he or she is unable to speak or move.

Diagnosis of ALS is based on the symptoms and on the results of various diagnostic procedures, including electromyography (an examination that meas- ures the electrical activity of the muscles), blood tests, muscle biopsies (removal of small samples of muscle tissue for microscopic examination), and computed tomography (CT) scanning and magnetic resonance imaging (MRI; see “Diag- nostic Procedures,” page 342).

There is no way to prevent the disease or to reverse or slow its progression. Most people with ALS die within 5 years of diagnosis. Treatment focuses on relieving discomfort and helping the person stay independent for as long as possible. The person’s life may be prolonged through the use of a ventilator (a machine that takes over breathing when a person can no longer breathe on his or her own) and feeding through a tube when a person has difficulty swallowing.

Epilepsy

In a person who has epilepsy, abnormal electrical activity in the brain causes seizures (temporary loss of consciousness or memory, or uncontrolled move- ments or behaviors). Epilepsy refers to a pattern of repeated seizures. The dis- order can result from a brain tumor, stroke, head injury, lead poisoning, alcohol or other drug withdrawal, metabolic imbalances, or brain infections (such as encephalitis or meningitis).

There are two basic categories of seizures: generalized seizures, which affect the entire brain, and partial seizures, which affect only one area of the brain. The two most common types of generalized seizures are grand mal seizures and petit mal (or absence) seizures. During a grand mal seizure, the person experiences loss of balance and coordination, loss of consciousness, and uncontrollable jerk- ing movements. In some cases the person may also experience loss of bladder or bowel control. A grand mal seizure can last for several minutes and leave the person disoriented and exhausted. The person usually does not remember the seizure.

Petit mal seizures occur most often in children. During a petit mal seizure, the person experiences loss of awareness that may last from a few seconds to about half a minute. Some people also experience brief confusion, muscle twitching, or rapid eye movements. The person is not aware of the seizure, and the symp- toms are often subtle and may go unnoticed; the person may appear to be inat- tentive or daydreaming. This type of seizure may occur hundreds of times per day, seriously impairing the ability to concentrate or complete even simple tasks.

During a simple partial seizure, a person may experience sudden muscle twitches, tingling sensations, or hallucinations that affect smell, taste, or vision. This type of seizure lasts for several minutes. The person is aware of the seizure as it occurs and can recall what happened afterward.

During a complex partial seizure, a person appears dazed and may perform involuntary actions such as walking in circles, laughing, speaking nonsensically, or smacking his or her lips. The person is not aware of his or her actions. After- ward the person is confused and does not remember the seizure.

A diagnosis of epilepsy is based on the results of a thorough neurological examination (see “Diagnostic Procedures,” page 342) and an evaluation of the

type and pattern of the person’s seizures. Because most people do not remember their seizures, information about the seizures is usually obtained from witnesses. The person will probably undergo an electroencephalogram (see “Diagnostic Procedures,” page 342) to examine the electrical activity of the brain. Computed tomography (CT) scanning or magnetic resonance imaging (MRI; see “Diag- nostic Procedures,” page 342) will probably be performed to rule out other pos- sible causes of the seizures, such as a brain tumor (see page 326) or a stroke (see page 323).

The risk of having a seizure increases with stress, sleep deprivation, fatigue, inadequate food intake, or failure to take prescribed medications. Seizures often occur spontaneously, but they can also be triggered by certain stimuli such as flickering or flashing lights, loud noises, or monotonous sounds. If you have grand mal seizures, you may be able to sense an oncoming seizure through feel- ings of unease or a recognizable sensory change (such as a specific sound, smell, or visual disturbance) called an aura.

Epilepsy is usually treated with anticonvulsant medications (such as primi- done or diazepam) that prevent or control seizures. In rare cases, if medication does not control the seizures, surgery may be performed to remove the affected brain tissue. A special diet helps some people. Biofeedback (see page 118) also may be helpful. Most people with epilepsy live normal, productive lives with the help of medication.

How to Help During a Seizure

Aperson who is having a seizure may lose consciousness, fall to the ground, and move about violently. Here are some things you can do to help ensure that a person is not injured during a seizure.

•   Do not panic.

•   Do not try to restrain the person.

•   Do not place your fingers or any object in the person’s mouth during the seizure.

•   Move away any large or sharp objects.

•   After the seizure, make sure nothing is blocking the person’s mouth or airway (such as food, gum, or dental devices).

•   Place the person on his or her side.

•   After the person regains consciousness, call a physician or take him or her to the near- est hospital emergency department.

•   Call 911 or your local emergency number if the seizure lasts longer than 5 minutes or if the person has not had a seizure before.

•   Call 911 if a second seizure begins shortly after the first seizure ends.

Multiple Sclerosis

Multiple sclerosis (MS) is a progressive, disabling disease of the central nervous system (the brain and spinal cord). MS is an autoimmune disease, in which the body’s immune system mistakenly attacks and destroys its own tissue (in this case, the myelin that surrounds and protects nerve cells). Early in the disease, inflammation occurs at random sites in the brain or spinal cord, damaging myelin and causing scarring (sclerosis) that interferes with the transmission of messages between the brain and the body.

The initial symptoms of MS may include blurred or double vision, red color distortion, or blindness in one eye. Muscle weakness, lack of coordination and balance, fatigue, partial or complete paralysis, and spasticity (stiffness) can occur in the early stages of the disease. Other symptoms include numbness, tingling, tremors, dizziness, and slurred speech. About half of all people with MS also experience problems with concentration, attention, memory, and judg- ment, although intellectual and language skills remain unchanged. Depression and paranoia can occur, as can inappropriate mood swings. Sexual dysfunction and loss of bowel and bladder control also can occur. The symptoms may worsen when the body heats up from high environmental temperature, exercise, taking a hot bath, or having a fever. Early in the disease, symptoms often come and go. Later they may gradually worsen.

The symptoms of MS usually appear between ages 20 and 40, although a diagnosis may not be made immediately. A diagnosis is based on eliminating other possible causes of the symptoms, such as stroke (see page 323) or a brain tumor (see page 326), and detecting characteristic features of MS. For example, certain changes in the brain can be observed with magnetic resonance imaging (MRI; see “Diagnostic Procedures,” page 342) after sufficient damage has occurred, and sometimes increased inflammatory proteins (antibodies) can be found in cerebrospinal fluid (obtained during a lumbar puncture; see “Diagnos- tic Procedures,” page 342). These antibodies, which are produced for no known reason, are strongly associated with MS. In some cases the doctor may perform an evoked response test, in which electrodes are placed on the person’s head, and electrical activity in the brain is recorded as he or she is exposed to various sen- sory stimuli such as sound or light.

The cause of MS is unknown. Evidence suggests that the disease may result from a combination of a person’s genetic susceptibility (the disease tends to run in families) and a viral infection early in life. Environment also appears to have a role in susceptibility to MS. People who spend the first 15 years of their lives in a temperate climate have a higher risk of developing the disease later in life than those who spend their f irst 15 years in a tropical climate. This is thought to be the period when the viral infection occurs in susceptible people.

Whites are twice as likely as blacks to develop MS, and women are twice as

likely to be affected as men (although, when the disease starts later in life, men are as likely as women to be affected). Most people with MS live a normal life span.

There is no cure for MS, although new treatments, such as interferon beta and glatiramer acetate, can reduce the likelihood of episodes and can slow progres- sion of symptoms. Treatment will depend on symptoms. Corticosteroids (such as dexamethasone, methylprednisolone, or prednisone) or adrenocorticotropic hor- mone are prescribed to control inflammation in the nervous system during acute episodes, especially when the symptoms affect movement rather than sensation. To relieve fatigue, your doctor may prescribe amantadine or modafinil. He or she also will advise you to help prevent fatigue by staying cool (such as with air con- ditioning).

The doctor may prescribe muscle relaxants to relieve muscle spasms and also may recommend that you swim or participate in a water therapy program. Phys- ical therapy can help maintain muscle strength and improve your balance and coordination. Occupational therapy can help you learn easier ways to perform daily tasks. For urinary incontinence, your doctor may prescribe an antispas- modic medication (such as dicyclomine or hyoscyamine) to relax the bladder and control muscle contractions.

Random Posts

Comments are closed.