Multiple Sclerosis: Subtypes, Symptoms, Diagnosis and Treatment

Definition: Multiple Sclerosis

Multiple sclerosis (MS), also known as disseminated sclerosis or encephalomyelitis disseminata, is an inflammatory disease in which the insulating covers of nerve cells in the brain and spinal cord are damaged. MS is a disease in which your immune system attacks the protective sheath (myelin) that covers your nerves. Myelin damage disrupts communication between your brain and the rest of your body. Ultimately, the nerves themselves may deteriorate, a process that's currently irreversible.

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Multiple sclerosis (MS) formerly known as disseminated sclerosis or encephalomyelitis disseminata), is a chronic, potentially debilitating disease that affects your brain and spinal cord (central nervous system).

An estimated 400,000 Americans have MS. It generally first occurs in people between the ages of 20 and 50. The disease is twice as common in women as in men.

The illness is probably an autoimmune disease, which means your immune system responds as if part of your body is a foreign substance.

The name multiple sclerosis refers to the scars (scleroses - better known as plaques or lesions) in the white matter. Multiple sclerosis may take several forms, with new symptoms occurring either in discrete attacks (relapsing forms) or slowly accumulating over time (progressive forms).

MS can cause a variety of symptoms, including changes in sensation (hypoesthesia), muscle weakness, abnormal muscle spasms, or difficulty in moving; difficulties with coordination and balance (ataxia); problems in speech (dysarthria) or swallowing (dysphagia), visual problems (nystagmus, optic neuritis, or diplopia), fatigue and acute or chronic pain syndromes, bladder and bowel difficulties, cognitive impairment, or emotional symptomatology (mainly depression).

MS affects the neurons in the areas of the brain and spinal cord known as the white matter.

These cells carry signals in between the grey matter areas, where the processing is done, and between these and the rest of the body.

In MS, your body directs antibodies and white blood cells against proteins in the myelin sheath surrounding nerves in your brain and spinal cord. This causes inflammation and injury to the sheath and ultimately to your nerves. The result may be multiple areas of scarring (sclerosis). The damage slows or blocks muscle coordination, visual sensation and other nerve signals.

Multiple sclerosis relapses are often unpredictable and can occur without warning with no obvious inciting factors. Some attacks, however, are preceded by common triggers. In general, relapses occur more frequently during spring and summer than during autumn and winter. Infections, such as the common cold, influenza, and gastroenteritis, increase the risk for a relapse.

The disease varies in severity, ranging from a mild illness to one that results in permanent disability.

Despite the ongoing efforts of medical scientists to reveal the factors responsible for causing multiple sclerosis, the exact reasons why the disorder occurs in otherwise healthy persons remain unknown.

Although various factors are suspected to trigger the occurrence of multiple sclerosis (viral or bacterial infections) or to facilitate its progression (genetic dysfunctions and various external, environmental factors), medical scientists haven't yet reached a consensus regarding the exact causes of the disorder.

At first, multiple sclerosis causes impairments only at the level of the central nervous system. In more advanced stages of progression, multiple sclerosis can involve virtually any innervated region of the body (any part of the body that contains a network of nerves). Without proper medical treatment - which is most effective when administered in early stages of disease - multiple sclerosis can cause a variety of disabilities and sometimes even death.

Depending on its patterns of progression, as well as the intensity and frequency of its generated symptoms, multiple sclerosis can be categorized in seven different subtypes:

• The first subtype of multiple sclerosis is the relapsing-remitting multiple sclerosis (RR MS), the most common form of the autoimmune disorder. According to statistics, more than 80 percent of all multiple sclerosis cases are of the relapsing-remitting subtype. This subtype is characterized by phases of symptomatic remission, followed by phases of relapse (characterized by sudden intensification of symptoms). The duration of the phases of relapse and remission vary from a patient to another, lasting anywhere from several weeks to several years.
• The second subtype of multiple sclerosis - primary-progressive multiple sclerosis (PP MS) accounts for around 20 percent of all multiple sclerosis cases. The major characteristics of this subtype are gradual progression of the disease, with very short phases of remission.
• The third multiple sclerosis subtype is similar to the PP MS subtype and is called secondary-progressive multiple sclerosis (SP MS). Patients with primary-progressive multiple sclerosis have 50 percent chances to eventually develop secondary-progressive multiple sclerosis.
• The fourth subtype of multiple sclerosis is called progressive-relapsing multiple sclerosis (PR MS) and is characterized by gradual progression with frequent phases of symptomatic exacerbation.
• The fifth multiple sclerosis subtype alternates between the primary-progressive, secondary-progressive and progressive-relapsing forms of the disease.
• The sixth multiple sclerosis subtype is benign multiple sclerosis, characterized by an initial symptomatic flare which can be followed by slow or no progression at all.
• The seventh and last multiple sclerosis subtype is also very rare. It is called malignant multiple sclerosis and involves rapid progression and very intense symptoms. This subtype is in most cases deadly.

Although there is no known cure for multiple sclerosis, several therapies have proven helpful. The primary aims of therapy are returning function after an attack, preventing new attacks, and preventing disability.

Update: (24 Nov, 2014) Discovery by NUS researchers contributes towards future treatment of multiple sclerosis

A new type of T cell, TH-GM, produces a cytokine, GM-CSF, to recruit and activate other inflammatory cells, including macrophages, to cause neuroinflammation, demyelination and nerve system damage. Illustration Credit: National University of Singapore

A multi-disciplinary research team from the National University of Singapore (NUS) has made a breakthrough discovery of a new type of immune cells that may help in the development of a future treatment for multiple sclerosis (MS).

The team found that a new type of immune T helper cells named TH-GM cells play a crucial role in the immune system and pathogenesis of neuronal inflammation. The findings shed light on a possible new avenue for therapeutic intervention, which can be used independently or in conjunction with other treatment options to improve outcomes in the treatment of MS.

Team showed that STAT5, a member of the STAT family of proteins, programs TH-GM and initiates the immune response to an auto-antigen in responding to a signal from an interleukin, IL-7, causing neuro-inflammation, pathogenesis and damage in the central nervous system. Blocking IL-7 or STAT5 would provide a significant therapeutic benefit for this disease. The study was first published online on 21 November in the journal Cell Research by Nature Publishing Group.

The STAT family of proteins and their signaling pathway (called JAK-STAT) were originally discovered by Prof Fu and his colleagues in 1992. Disturbance of this pathway was shown to be a major cause for many kinds of inflammatory diseases. The newly discovered IL-7-STAT5 by Prof Fu and his team in neuro-inflammation significantly expands this line of medical research, development and therapeutic intervention in a number of major diseases.

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Quick Facts: Multiple Sclerosis Genetics

MS is not considered a hereditary disease; however, a number of genetic variations have been shown to increase the risk. The probability is higher in relatives of an affected person, with a greater risk among those more closely related. In identical twins both are affected about 30% of the time, while around 5% for non-identical twins and 2.5% of siblings are affected with a lower percentage of half-siblings. If both parents are affected the risk in their children is 10 times that of the general population. MS is also more common in some ethnic groups than others.

Statistics: U.S. Multiple Sclerosis

• The average age when MS symptoms first appear is between the ages of 30 and 35 years.
• MS is more common among Caucasians and among people of Northern or Central European descent.
• MS is much more common in females than males, about 2 to 3 times more common in relapsing-remitting MS. This is also true for other autoimmune diseases, like rheumatoid arthritis.
• MS is the most widespread disabling neurological condition of young adults around the world. You can get MS at any age, but most people are diagnosed between the ages of 20 and 40.
• It's estimated that more than 400,000 people in the United States and about 2.5 million people around the world have MS. In the United States, about 200 new cases are diagnosed each week.