What Is Multiple Sclerosis (MS)?
Multiple sclerosis (MS) can be thought of as an immune-mediated inflammatory process involving different areas of the central nervous system (CNS) at various points in time. As the name suggests,
the condition affects many areas of the central nervous system or CNS. Nerves
are surrounded by a myelin sheath to insulate and protect them from damage. This
sheath also allows effects how fast nerve signals get from the brain or spinal
cord (CNS) to the affected body part. As this sheath is destroyed the nerve
conduction to that body area or part decreases or is interrupted completely. The destruction is caused by the body's immune system attacking the myelin sheath. The reason that the body's immune system attacks the sheath is not understood fully, but it is believed to be related to a combination of a genetic predisposition and acquired or environmental influences.
How Common Is MS?
- MS is more common in individuals of northern European descent.
- Women are more than twice as likely to develop multiple sclerosis as men.
- Multiple sclerosis usually affects people between the ages of 20 and 50 years, and the average age of onset is approximately 34 years.
How Does the CNS Effect Nerve Signals in MS (Causes)?
The central nervous system is made up of the brain and spinal cord. They process information from our environment and control voluntary muscle movements to allow the body to do certain things.
- When you touch something hot, for example, signals are sent from sensory nerve endings in your hand up long nerves in your arm, eventually reaching the spinal cord.
- From there, the signal is transferred up your spinal cord to your brain, where the information is processed. Your brain then sends a signal back down the spinal cord to the nerves in your arm.
- These nerves cause the muscles in your arm to contract, pulling your hand away from the heat.
This neural system works efficiently, unless there is a disease process affecting the pathways in the spinal cord and brain. MS is one of the diseases that can affect these pathways.
- Signals are transmitted within the central nervous system along pathways.
- These pathways are made up of long fibers called nerves.
- Nerves are capable of transmitting information from the environment to the brain.
- Everything you see, touch, taste, smell, or feel is transmitted along nerves to your brain.
- Nerves also carry information responsible for our alertness, behavior, ability to understand and think rationally, capacity to communicate with others, and feeling and interpreting emotions.
- To help transmit all this information in a timely manner, the nerves are covered by a fatty substance called myelin. Myelin insulates the nerves and allows them to transmit information to and from the brain in a fraction of a second.
- If the myelin is disrupted in any way, the transmitted information is not only delayed, but it may also be misinterpreted by the brain.
- This autoimmune destruction of the myelin sheath leads to areas of demyelination (also known as plaques) in the brain and spinal cord.
- These plaques disrupt the transmission of information in the CNS and lead to the symptoms seen in MS.
What Are the Symptoms and Signs of MS?
The symptoms of MS can be different from person to person. Visual, sensory, and motor signs and symptoms are all part of MS. The clinical manifestations are varied, and therefore there is a wide range of symptoms that can appear. Some people have mild cases of MS with little or no disability over the years. Others have more severe types of MS, requiring confinement to a wheelchair or bed.
Over 30% of those affected with MS will have significant disability after 20 to 25 years. Still others may live their entire lives symptom-free (some individuals without multiple sclerosis symptoms are found incidentally to have multiple sclerosis lesions by MRI, or individuals in whom an examination of their brain after death unexpectedly reveals that they were affected by the disease). This variability makes it difficult in some cases to diagnose multiple sclerosis. Often the signs and symptoms are mistaken as being psychiatric in origin.
Medically Reviewed by a Doctor on 3/14/2017
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