What is MS?

Multiple sclerosis (MS) is an autoimmune disease that can affect your life in many ways.

Approximately 2.8 million people worldwide have MS. While there is no known cure, treatment options have expanded over the last decades, and ongoing research continues to address MS, its symptoms, and its causes.

MS affects your central nervous system

MS is an autoimmune disease where your own immune cells attack your central nervous system (CNS). The CNS includes your brain, spinal cord, and optic nerves.

Normally, immune cells patrol for signs of infection (such as viruses and bacteria). When they find one, they attack it. Generally, B cells make antibodies that help the immune system recognize the infectious substance, and T cells attack the infectious substance and help control the immune response.

The CNS operates by sending signals through the nerve cells, also called neurons. These neurons help you process and respond to the world around you.

MS impacts the communication between neurons

Myelin is a substance that forms a protective layer over parts of individual neurons in the CNS. This helps neurons send signals rapidly.

In MS, for unknown reasons, immune cells attack myelin, damaging or destroying it and causing inflammation.

When myelin is damaged or destroyed, it becomes harder for neurons to communicate with each other quickly and effectively. The neurons themselves can also be damaged in MS.

Areas where inflammation has damaged or destroyed myelin are called lesions. Your healthcare professional can often see these lesions using magnetic resonance imaging (MRI).

Everyone experiences brain atrophy (also known as brain shrinking) with age. However, the occurrence of lesions in patients with MS speeds up brain atrophy. Brain atrophy appears early in the course of the disease and accelerates with MS progression.

Consider the below for an example of how MS can impact communication in the CNS

Neural networks are like well-maintained highways throughout the brain.

With MS, these highways become damaged and, over time, may become disconnected. This can cause signals to move slower and less efficiently within neural networks.

The brain can build new connections to try and repair damage. However, its ability to build these new connections decreases over time.

As the brain tries to build so many new connections, it can become less efficient. Think of it like taking a detour or a dirt road—you can still get to your destination, but it usually takes longer. This means your brain may process information slower than those who do not have MS, and it may take you longer to think through simple daily tasks.

MS can take time to diagnose

There’s no single test that can diagnose MS, so healthcare professionals must use a variety of methods to evaluate people for MS. They’ll take a detailed medical history, perform a neurologic exam, and may order different kinds of tests. These tests include MRIs, spinal fluid tests, and blood tests.

If the results of these tests and exams meet certain criteria, an MS diagnosis is given.

Before being diagnosed with MS, a person can experience radiologically
isolated syndrome (RIS) or clinically isolated syndrome (CIS)

RIS: Experienced in people who had an MRI that showed an abnormality in their brain or spinal cord that looked similar to an MS lesion. These individuals have no past or current neurologic symptoms at the time the abnormality is found.

CIS: Experienced in people who have a first episode of neurologic symptoms caused by inflammation in the CNS and damage to myelin. The signs and symptoms of CIS are similar to those of MS but don’t yet meet the full criteria for an MS diagnosis.

Diagnosed MS can take a few forms. These include relapsing-remitting MS (RRMS), secondary progressive MS (SPMS) with or without relapses, and primary progressive MS (PPMS).

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MS symptoms