By Dr. Joseph Berger
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If you or someone you care about has multiple sclerosis (MS), educating yourself about the disease and how it's treated is an important step that can benefit you and those you love. Current estimates indicate that 450,000 persons in the United States suffer from MS. It is the second most common crippling illness of young adults, following traumatic injury.
MS is a disease of the central nervous system affecting the brain, spinal cord and optic nerves.
The disease is an autoimmune disorder, in which the body’s immune system mounts an attack against myelin, the white matter of the central nervous system, leading to a loss of the nerves' insulation. As a consequence, conduction along the nerve is slowed, and the nerve itself may suffer irreparable damage. The sites of injury in the nervous system vary, and the symptoms vary accordingly. Among the more common problems are impaired vision, weakness, numbness, gait abnormalities, balance problems, and disorders of bowel and bladder function.
There are no specific symptoms or tests that can determine if a person has MS. Several strategies are used to determine if a person meets the long-established criteria for a diagnosis of MS and to rule out other possible causes of symptoms. These include a medical history and neurologic exam as well as other various tests.
Prior to the early 1990s, physicians were often reluctant to tell patients that they had MS because there were no effective therapies available. That changed in 1993, with the introduction of Betaseron (interferon-beta). Within the next 10 years, other formulations of interferon-beta (Avonex and Rebif), as well as similarly effective novel compounds that mimic the protein structure of myelin (Copaxone), were introduced to market.
These therapies ushered in a new era of hope in the treatment of multiple sclerosis and have significantly altered the natural history of the disease. However, they are not cures. In some patients the disease progresses even with treatment. The precise mechanisms by which these drugs work has not been fully clarified, although the best evidence suggests that they work by subtly altering the immune system. Repeated studies have demonstrated that these drugs are more effective the earlier in the course of the disease they are used.
In 2006, a novel form of therapy (Tysabri) became available. This therapy, administered intravenously every month, is an antibody that binds to sites on inflammatory cells, thus preventing their entry into the brain and the attendant inflammation and myelin loss. While Tysabri may have greater efficacy, it is associated with greater risk, in particular, the rare risk of a fatal brain infection known as progressive multifocal leukoencephalopathy.
Currently, excitement in the MS community is very high, because a large number of drugs under investigation seem to be especially promising in treating the disease. Several of these drugs will likely come to market in the next one to two years and include agents that may be taken by mouth. Currently, all MS drugs are administered by injection.
The University of Kentucky is one of the sites where some of these drugs are being investigated. While these new therapies could prove more effective than the drugs currently used, they could also carry increased risks. Managing patients with MS will most likely be a careful balancing act, almost certainly requiring heightened vigilance for the development of complications from these therapies.
Dr. Joseph Berger is chair of the Department of Neurology in the University of Kentucky College of Medicine.