Multiple sclerosis

Multiple sclerosis usually causes periods of worsening symptoms followed by periods of recovery. Understanding how the disease affects your body can help you manage symptoms and improve your quality of life.

What is multiple sclerosis?

Multiple sclerosis (MS) is an autoimmune disease that affects your brain and spinal cord. Your immune system attacks healthy tissue, called myelin, in your nerve cells.

Myelin forms an insulating layer called a sheath around nerve cells. The myelin sheath protects cells and helps signals pass between them.

MS is a type of demyelinating disease, which means it causes myelin to break down over time. This breakdown slows down or blocks messages between your brain and your body.

Causes of multiple sclerosis

Experts don't know the exact cause of MS. A viral infection or gene change (mutation) may trigger your immune system to begin attacking myelin. Your environment and lifestyle may also play a role in causing MS, depending on your existing risk.

Multiple sclerosis symptoms

MS can cause a variety of mild to severe symptoms throughout your body. You may have periods of more or stronger symptoms, called attacks, flare-ups or relapses. These periods can last anywhere from days to months. Or you may have ongoing symptoms that worsen slowly over time.

MS often leads to changes in your:

• Bowel and bladder function
• Cognitive abilities, such as thinking and attention
• Mood
• Sex drive (libido)
• Speech and swallowing abilities
• Vision

You may also experience other neurologic symptoms, such as:

• Dizziness or loss of balance
• Muscles spasms
• Numbness, tingling or pain
• Uncontrollable shaking (tremor) in your arm or leg
• Weakness or trouble moving your hand, arm or leg

Types of multiple sclerosis

MS is usually a lifelong disease once it develops. Doctors classify MS into four main types:

• Clinically isolated syndrome (CIS): Your doctor may diagnose you with CIS if you have had one attack of MS-like symptoms but do not meet all the criteria for MS. MS may or may not develop after CIS.
• Relapsing-remitting MS (RRMS): RRMS is the most common type, occurring in about 85% of people with MS. It causes cycles of a flare-up followed by remission.
• Secondary progressive MS (SPMS): SPMS is an advanced form of RRMS. It involves more severe attacks with less recovery in between attacks.
• Primary progressive MS (PPMS): PPMS is a type of MS that develops gradually. You experience more and worsening symptoms over time.

Each type of MS develops differently over time and affects everyone differently. Knowing the type of MS helps your provider recommend the most effective treatment possible. It can also help you understand what to expect from life with MS.

Multiple sclerosis diagnosis

No single test can tell your doctor if you have MS. Your doctor will do a comprehensive evaluation to understand your neurologic health and rule out other possible diseases.

They will discuss your symptoms, health history and family history with you. They may also learn more information through tests such as:

• Blood tests to help check for other diseases
• MRI, an imaging test that can show brain and spinal cord damage
• Neurologic exam to check how well your nervous system works, such as your vision, movement and balance
• Spinal tap (lumbar puncture), which involves taking and analyzing a sample of the fluid surrounding your brain and spinal cord

Multiple sclerosis risk factors

Certain factors may increase your risk of developing MS, including:

• Age: MS can affect people of all ages, but it most often develops between ages 20 and 40.
• Infection: You face a higher risk for MS if you’ve had the Epstein-Barr virus (EBV). But not everyone with EBV will develop MS.
• Sex assigned at birth: MS affects more females than males.
• Tobacco use: Smoking increases your risk for MS.

Complications of multiple sclerosis

MS can lead to other serious health problems as it worsens. You may need additional care to prevent or treat complications, such as:

• Balance disorders and loss of movement abilities
• Constipation
• Depression
• Pain
• Seizures or stroke
• Sleep disturbances, such as obstructive sleep apnea
• Thinking and memory problems
• Urinary tract and respiratory infections

Multiple sclerosis prevention

There’s no sure way to prevent MS, but you may be able to reduce your risk, such as not smoking. Tell your health care provider immediately if you experience any MS symptoms. Early CIS treatment can help delay the development of MS.

If you have MS, certain things may also worsen your symptoms or trigger a flare-up, including:

• Hot baths, saunas or steam rooms
• Prolonged sun exposure
• Stress