What Is Multiple Sclerosis?
(Source: WebMD)
Multiple sclerosis or MS is a disease that affects the brain and spinal cord, resulting in loss of muscle control, vision, balance, and sensation (such as numbness). With MS, the nerves of the brain and spinal cord are damaged by one's own immune system. Thus, the condition is called an autoimmune disease.
Autoimmune diseases are those whereby the body's immune system, which normally targets and destroys substances foreign to the body such as bacteria, mistakenly attacks normal tissues. In MS, the immune system attacks the brain and spinal cord, the two components of the central nervous system. Other autoimmune diseases include lupus and rheumatoid arthritis.
The central nervous system is made up of nerves that act as the body's messenger system. Each nerve is covered by a fatty substance called myelin, which insulates the nerves and helps in the transmission of nerve impulses, or messages, between the brain and other parts of the body. These messages control muscle movements, such as walking and talking.
MS gets its name from the buildup of scar tissue (sclerosis) in the brain and/or spinal cord. The scar tissue or plaques form when the protective and insulating myelin covering the nerves is destroyed, a process called demyelination. Without the myelin, electrical signals transmitted throughout the brain and spinal cord are disrupted or halted. The brain then becomes unable to send and to receive messages. It is this breakdown of communication that causes the symptoms of MS.
Although the nerves can regain myelin, this process is not fast enough to outpace the deterioration that occurs in MS. The types of symptoms, severity of symptoms, and the course of MS vary widely, partly due to the location of the scar tissue and the extent of demyelination.
According to the National Multiple Sclerosis Society, the condition affects approximately 400,000 Americans and is, with the exception of trauma, the most frequent cause of neurological disability beginning in early to middle adulthood.
MS is two to three times as common in females as in males and its occurrence is unusual before adolescence. A person has an increased risk of developing the disease from the teen years to age 50, with the risk gradually declining thereafter.
What Causes Multiple Sclerosis?
No one is sure what causes the body's immune system to go awry in multiple sclerosis. Some scientists believe that it is a combination of genetics and something in the environment to which the person was exposed to early in life.
What Are the Symptoms of Multiple Sclerosis?
Symptoms of multiple sclerosis vary from person to person and can change over time in the same person. The most common early symptoms include:
- Muscle weakness
- Decreased coordination
- Blurred or hazy vision
- Eye pain
- Double vision
As the disease progresses, symptoms may include muscle stiffness (spasticity), pain, difficulty controlling urination, or problems with cognition.
How Is Multiple Sclerosis Diagnosed?
Making the diagnosis of multiple sclerosis isn't easy, because the symptoms are vague and often fleeting. Factors that a health professional considers are:
- Two or more isolated episodes of symptoms that could be caused by MS. The episodes must last at least 24 hours and occur a month apart.
- MRI test showing the areas of demyelination (lesions).
There are other tests that a health professional may perform.
How Is Multiple Sclerosis Treated?
There are a variety of medications available that can reduce the frequency and severity of symptoms in some people with multiple sclerosis. Some drugs can also slow the progression of certain types of MS.
There are also a variety of medications available that can:
- Shorten attacks of MS (acute worsening of symptoms)
- Relieve the symptoms of MS (such as pain, urinary problems, and muscle stiffness)
(Source: WedMD)
Diagnosing Multiple Sclerosis
There is no single test that is proof-positive for diagnosing multiple sclerosis. However, there are accepted criteria for making the diagnosis, but even this system is imperfect.
Since diagnosing MS can be very difficult, a neurologist who specializes in treating MS should evaluate your symptoms. As many as 10% of people diagnosed with multiple sclerosis actually have some other condition that mimics MS. Examples of other conditions that masquerade as MS include inflammation in the blood vessels, multiple strokes, vitamin deficiency, lupus, or a brain infection. Sometimes stress-related disorders can lead to a misdiagnosis of MS.
How Is a Diagnosis of Multiple Sclerosis Made?
An accurate diagnosis of multiple sclerosis is based on your medical history and a neurological exam (an exam of the function of the brain and spinal cord) using various tests. A lot depends on the skill of the doctor in asking the right questions to uncover information and to properly evaluate the signs and symptoms of a malfunctioning brain or spinal cord.
In addition to a thorough medical history and exam, a variety of specialized procedures are helpful in accurately diagnosing MS. These include imaging techniques, such as MRI, spinal taps or lumbar punctures (examination of the cerebrospinal fluid that runs through the spinal column), evoked potentials (electrical tests to help determine if MS has affected a person's nerve pathways), and lab analysis of blood samples.
What Are the Accepted Criteria for a Diagnosis of Multiple Sclerosis?
- Multiple sclerosis usually begins between 20 and 50 years of age
- Symptoms and signs indicating disease of the brain or spinal cord
- Evidence of two or more lesions -- or abnormal areas on the brain -- from a MRI scan
- Objective evidence of disease of the brain or spinal cord on doctor's exam
- Two or more episodes lasting at least 24 hours and occurring at least one month apart
- No other explanation for the symptoms
What Does an MRI Show?
MRI is the best test to view the changes caused by multiple sclerosis. The precise image produced by MRI gives the neurologist clear evidence of inflammation in the deep parts of the brain or spinal cord that is characteristic of MS.
However, abnormal spots on the brain MRI can be caused by other conditions, so before making a diagnosis your doctor will consider all information including your symptoms and scan results. Similar lesions can be seen in older people or people with high blood pressure and diabetes.
Also, a normal MRI does not absolutely rule out a diagnosis of MS. About 5% of patients who are confirmed to have MS on the basis of other criteria, do not have lesions in the brain on MRI. These people may have lesions in the spinal cord or may have lesions that cannot be detected by MRI.
Will I Need a Spinal Tap (Lumbar Puncture) to Diagnose MS?
Performing a spinal tap to examine the cerebrospinal fluid may be helpful in diagnosing MS in some people, but it is no longer considered necessary in all instances.
Experienced specialists will be able to determine if you need this test to confirm a suspected diagnosis of MS, particularly if your history and exam suggest the presence of the disease. Abnormalities that may appear in the cerebrospinal fluid can be very helpful in establishing a diagnosis but, like other tests, spinal taps are not foolproof in diagnosing MS.
What Other Tests Are Performed to Diagnose Multiple Sclerosis?
Electrical tests of the nerve pathways, known as evoked potentials, may be helpful in confirming whether MS has affected the visual, auditory, or sensory pathways. These tests are done by placing wires on the scalp to test the brain's response to certain types of stimulation, such as watching a pattern on a video screen, hearing a series of clicks, or receiving electrical impulses in your arm or leg.
Your doctor may order a blood test to help rule out conditions that mimic multiple sclerosis, but the presence of MS cannot be detected in the blood.
Accepting the Diagnosis of Multiple Sclerosis
The diagnosis of multiple sclerosis can be a lengthy process. Upon hearing the diagnosis, you may feel a mixture of emotions, including denial, fear, relief, optimism, or hope. For some people, a diagnosis after months or years of symptoms is a relief, but for others it may be shocking. Even when a diagnosis of MS is made, the uncertainty is not over. You may have some concerns about the unknown elements of the disease, its course and its impact. This is completely understandable. The course of MS is unpredictable; not knowing how the disease will affect you over the long term is probably the most difficult factor to deal with. Sharing your thoughts and emotions with others can help you cope with the diagnosis. Remember that MS affects everyone differently so what one person with MS experiences may not be what you will experience. To learn more about coping with a diagnosis of MS, visit Living With MS.
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