Diagnosing Multiple Sclerosis (MS)
What is multiple sclerosis?
Multiple sclerosis (MS) is an autoimmune disease that affects the central nervous system. With MS, the immune system attacks the protective shell (myelin) of nerve fibers throughout the body. Scar tissue then accumulates around the nerves, which eventually causes nerve damage. Once the nerves are damaged with scar tissue, they cannot receive signals sent from the brain to properly operate. Since the nervous system controls every movement of the body, MS can cause vision issues, movement and muscle control problems, balance issues, and other health complications. The exact cause of multiple sclerosis is not yet clear.
While no single test exists to diagnose multiple sclerosis, various medical tests can eliminate the possibility of other conditions with similar symptoms, leading to a diagnosis of MS.
The diagnostic process typically starts with a physical examination, neurological examination, and thorough medical history followed by several medical tests, including the following:
- Blood tests
Blood tests do not directly show MS, but they can rule out other conditions such as Lyme disease, syphilis, HIV/AIDS or vitamin deficiencies.
- Magnetic resonance imaging (MRI)
An MRI can rule out other medical conditions, such as brain tumors. It can also show demyelination, which is when the layer of myelin that surrounds nerve fibers is damaged (the hallmark of MS).
- Lumbar puncture
In addition to ruling out conditions with similar symptoms, a lumbar puncture can show elevated IgG antibodies, certain proteins called oligoclonal bands, and abnormally high amounts of white blood cells (all commonly found in individuals with MS).
- Evoked potential test
Evoked potential (EP) tests may show impaired transmission of electrical signals along the optic nerve pathways. Although this impairment can be caused by an ocular or retinal disorder, it can also be an early sign of MS.
The accepted criteria for a diagnosis of multiple sclerosis include the following:
- Onset of symptoms between the ages of 10 and 60
- MRI evidence of two or more lesions in the deep parts of the brain or spinal cord
- Evidence of central nervous system disease during neurological examination
- Two or more episodes of symptoms lasting at least 24 hours and occurring at least one month apart or a progression of symptoms over at least six months
- No other explanation for symptoms
A diagnosis of multiple sclerosis is typically made by a neurologist who specializes in treating the condition. MS is a very difficult condition to diagnose. It is estimated that up to 10 percent of people diagnosed with MS actually have a different medical condition that mimics MS, such as blood vessel inflammation, a vitamin deficiency or a brain infection.