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Multiple Sclerosis Glossary

Acquired immune deficiency syndrome (AIDS)
Acquired immune deficiency syndrome (AIDS) is the last stage of human immunodeficiency virus (HIV) disease, a viral disease that slowly destroys the body's immune system. AIDS is typically diagnosed when a person's number of immune system CD4 cells, or T-cells, drops below 200. When a person is diagnosed with AIDS, he or she also has become affected by diseases and conditions, possibly including cancer, which may attack the body in the absence of a strong, uncompromised immune system.

A protein produced by the body's immune system that recognizes and helps fight infections and other foreign substances in the body.

Autoimmune disease
An autoimmune disease is one in which the immune system attacks the body's own tissues.

Clinical trial
Clinical trials are scientific studies involving humans that help researchers gain a better understanding of how new treatments and vaccines work. In a clinical trial, researchers hope to answer questions about the new treatment, as well as to evaluate its safety and efficacy. There are ethical and legal regulations that clinical trials in the United States are required to follow.

Cognitive function
Cognitive difficulties are problems with cognitive functioning, which include the intellectual activities of thinking, reasoning, remembering, imagining, or learning words.

Crohn's disease
Crohn's disease is a disorder that causes parts of the digestive tract to become inflamed and swell. Crohn's most commonly affects the lower small intestine, or the ileum, but it can affect any portion of the digestive tract. The most common symptoms of Crohn's disease are diarrhea and abdominal pain.

Genetic predisposition
Having a genetic predisposition to a condition, disorder, or disease means that a person's inherited genetic composition makes it more likely that he or she will develop that condition, disorder, or disease. If the genetic makeup of potential parents makes it likely that their child will be predisposed to a serious genetic disorder, genetic counseling with a healthcare professional is usually recommended.

Glatiramer acetate
Glatiramer acetate is a treatment for relapsing-remitting multiple sclerosis (MS) that may extend the amount of time between relapses.

Human immunodeficiency virus (HIV) infection
Human immunodeficiency virus (HIV) destroys the body's immune system, thereby leaving the body open to attack by other viruses, bacteria, or other harmful foreign substances. After HIV has destroyed a certain amount of the body's immune system, the infection progresses to acquired immune deficiency syndrome (AIDS). To date, there is no way for HIV to be completely eradicated once it enters the body.

Immune system
The immune system protects the body against potentially harmful substances, also called antigens. When the immune system detects an antigen, it initiates the immune response. This is a complex series of events that work together to eliminate the threat the antigen poses to the body.

Immunomodulators are a type of treatment that can be used in patients with relapsing forms of multiple sclerosis. Immunomodulators work to alter a patient's immune system so that the MS disease course may change. This may result in fewer and less severe multiple sclerosis symptoms, and also slow the disease's progression. When immunomodulators work, they can reduce a patient's chances of disability, and thereby have the potential to enhance future quality of life.

Intravenous (IV)
The passing of medicines into a vein through a needle attached to a tube.

An infusion is the process of flowing a solution into the body, usually through a vein.

Interferon is a protein the human body produces to help defend cells against viral attacks. Certain types of interferon can be used in the treatment of chronic hepatitis B, chronic hepatitis C, multiple sclerosis (MS), and some types of cancer.

An MS lesion, or plaque, is an area of the central nervous system's myelin sheath that has started to deteriorate. This process is also called demyelination. An MRI test can be used to create an image of the MS lesion.

Leukemia is cancer of the blood that occurs when bone marrow begins to produce abnormal white blood cells, or leukemia cells. These abnormal cells eventually begin to outnumber other cells in the blood, making it difficult for the blood to do its job in the body properly. There are many different types of leukemia, each named for the type of leukemia cell most present in the body.

Lymphoma is a type of blood cancer that starts in the lymphatic system, a part of the body's immune system. The lymphatic system includes lymph nodes, the spleen, the liver, and bone marrow. When a person has lymphoma, the lymphocytes, or white blood cells, in the lymphatic system become lymphoma cells. The lymphoma cells then reproduce to create lymphoma cell masses, which can crowd out and hinder the other, healthy cells working in that part of the body.

Magnetic resonance imaging (MRI)
Magnetic resonance imaging (MRI) is a method of creating images of the inside of the body. MRI uses powerful magnets and radio waves to produce these images. Along with other devices, MRI may help confirm or determine a diagnosis. MRI can be particularly helpful when diagnosing disorders of the brain or spine because they can provide detailed pictures of certain regions of the body that are difficult to see using other types of scanning devices.

Mechanism of action
A mechanism of action describes the physical and chemical processes that bring about a particular action or reaction. For example, the mechanism of action of a drug details how exactly the drug reacts with body cells, tissue, or organs to produce the intended outcome.

Mental function (see cognitive function)

MS fatigue
Multiple sclerosis fatigue is a type of fatigue that can affect 75% to 95% of multiple sclerosis patients, and can affect a person's ability to complete simple, daily tasks. It may occur because the energy required for him or her to move or breathe is far greater than the energy a non-MS patient would need to do the same thing. This can leave a patient completely exhausted. There are energy-conserving techniques related to fatigue due to mobility and respiratory problems that a patient can learn to help him or her treat MS fatigue. If these don't help, the fatigue may be classified as primary MS fatigue. This is normally treated with a variety of lifestyle changes.

It may take some time to diagnose and treat MS fatigue because of the need to eliminate all other possible diagnoses, and to work out a viable treatment plan.

Multiple sclerosis (MS)
Multiple sclerosis (MS) is a disease that affects the brain and spinal cord. It is thought to be an autoimmune disease, and it is characterized by the demyelination, or destruction, of myelin sheath. Myelin sheath is the protective covering for the nerve fibers of the central nervous system, and helps the nerve fibers transmit electrical impulses between different parts of the body. When myelin sheath is destroyed in MS, messages between different parts of the body are not transmitted as effectively. After the myelin is destroyed, scar tissue called sclerosis is left behind in the damaged areas, which are referred to as lesions or plaques. This damage to the nervous system can result in a myriad of symptoms, including vision problems and difficulty with muscle movement, coordination, and balance.

There are 4 clinical types of MS: relapsing-remitting, primary-progressive, secondary-progressive, and progressive-relapsing.

Multiple sclerosis (MS): Primary-progressive
Primary-progressive multiple sclerosis (PPMS) accounts for about 10% of MS diagnoses. This type of MS is characterized by a slow and steady worsening of symptoms. There are relapses in PPMS, but the worsening of symptoms may occasionally speed up, slow down, or even get better for a time.

Multiple sclerosis (MS): Progressive-relapsing
Progressive-relapsing multiple sclerosis (PRMS) affects about 5% of people with MS. It is characterized by steady worsening of symptoms and occasional relapses.

Multiple sclerosis (MS): Relapsing-remitting
Relapsing-remitting multiple sclerosis (RRMS) accounts for about 85% of all initial MS diagnoses. People with RRMS have isolated relapses. When not having a relapse, someone with RRMS is partially or completely without symptoms.

Multiple sclerosis (MS): Secondary-progressive
About 50% of people with RRMS develop secondary-progressive multiple sclerosis (SPMS). This happens gradually, usually within 10 years of the initial MS diagnosis. People with SPMS have fewer and fewer relapses, but begin to have constant, steadily worsening symptoms.

Myelin sheath
Myelin sheath is the thick, soft, white, fatty layer of protective material around nerve fibers. This material is called myelin. If the myelin sheath around nerve fibers deteriorates or is destroyed, it can interfere with the fibers' ability to transmit messages successfully from one part of the body to another.

Nerves transmit messages between different parts of the body, including the brain, organs, muscles, and joints. Each nerve is a bundle of nerve fibers. Nerve fibers are composed of processes called axons and dendrites. These processes can be either afferent or efferent. Afferent processes lead toward the brain and transmit sensory stimuli to the brain from other parts of the body. Efferent processes lead away from the brain and direct bodily contractions, or movements.

The neuron is the type of cell that makes up nervous tissue. It consists of a nucleus and processes. The processes include axons and dendrites. Neurons transit impulses to and from the nervous tissue.

Nocturia causes a frequent need to awaken and urinate at night. People with nocturia may get up 6 or more times per night to urinate. Treatment for nocturia may involve medication and testing to determine underlying causes.

Organ transplantation
Organ transplantation involves removing part or all of an organ from one body and transferring it to another body.

A placebo is an inactive substance used in controlled experiments, such as clinical trials that are evaluating the efficacy and safety of a drug. While one group of experiment subjects is given the drug being investigated, another group is given the placebo. This placebo group is used as an untreated, similar population against which the treated group is compared.

Shingles (herpes zoster)
Shingles (herpes zoster) is a viral infection that affects adults. It is caused by the varicella-zoster virus, the same virus that causes chickenpox in children. When a person has shingles, he or she will break out in a painful rash on a portion of the body. Shingles is often triggered by stress in adults that had chickenpox as children, but it can also appear in people with weakened immune systems. This may include patients taking therapies that suppress the immune system, HIV/AIDS patients, and patients with certain types of cancer.

Spasticity is muscle stiffness and an inability to control the affected muscles. Treatment for spasticity may include physical and occupational therapy, as well as medication. Spasticity is one of the most common symptoms of multiple sclerosis (MS).

A transfusion (or "blood transfusion") is the flow of blood or blood plasma through a tube and needle into a person's vein or artery.

White blood cells
White blood cells, or leukocytes, defend the body by attacking and destroying antigens, such as viruses, bacteria, and other infections. They are produced in the bone marrow and are always present in the body. However, the number of white blood cells will usually increase significantly when they are fighting a disease or infection. The 5 types of white blood cells are lymphocytes, monocytes, neutrophils, basophils, and eosinophils.

A person's white blood cell count can be measured, and is sometimes used to determine if the body has an infection, or to find out if the body's immune response is working properly.

Important Safety Information

Please see full Prescribing Information (PDF) , including Boxed Warning and
Patient Medication Guide (PDF) .

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