Multiple sclerosis (MS) is a disease that affects your brain and spinal cord, also called the central nervous system. MS damages myelin, the protective coating around your nerve cells. Myelin helps nerves send messages quickly. When it's damaged, messages between your brain and body slow down or get blocked. This leads to MS symptoms.

Not everyone with MS has the same experience. MS is grouped into types based on how the disease changes over time. Types of MS include:

• Relapsing-remitting MS. The most common type. People have flare-ups of new or worsening symptoms (relapses), followed by periods of recovery with few or no symptoms.
• Secondary-progressive MS. Some people with relapse-remitting MS later develop this type. Symptoms slowly get worse over time, with fewer or no recovery periods.
• Primary-progressive MS. Symptoms slowly worsen from the start, without clear relapses or periods of recovery.
• Clinically isolated syndrome. A single episode of symptoms like MS that last at least 24 hours. It may be an early sign of MS, but not everyone develops MS afterward.
• Radiologically isolated syndrome. Brain changes that look like MS show up on an MRI, but the person has no symptoms. Some people go on to develop MS symptoms, and some do not.

No one knows the exact cause of MS. Many believe it is an autoimmune disease. This means your immune system mistakenly attacks healthy cells. In MS, the immune system attacks myelin.

Several factors may work together to raise the risk of MS, including:

• A previous infection with Epstein-Barr virus, which is the most common cause of mononucleosis (mono).
• Environmental influences, such as smoking, little sun exposure, or low levels of vitamin D.
• Genetic factors, such as certain genes. These are parts of DNA in your cells that are passed down from your parents. Having certain genes may increase your risk of MS, but not everyone with these genes gets the disease.
• A family history of MS, meaning having a close relative who has been diagnosed with MS.
• Your sex, since MS is two to three times more common in women than in men.
• Your age, since MS most often begins between the ages of 20 and 40.

MS symptoms vary from person to person. Some people have mild symptoms, while others may have more serious problems. Symptoms depend on which nerves are affected. Common symptoms may include:

• Blurry or double vision, or eye pain (often due to optic neuritis)
• Trouble with bladder control
• Muscle weakness
• Muscle stiffness or spasms
• Trouble with coordination, walking, or balance
• Numbness, tingling, or a "pins and needles" feeling
• Thinking or memory problems
• Fatigue
• Dizziness or vertigo
• Mood changes

There is no specific test for MS. Your health care provider may use several tools to make a diagnosis, including:

• A review of your health history and symptoms
• A physical exam and neurological exam, which checks your reflexes, strength, and senses
• An MRI scan to look for damage in the brain and spinal cord
• Blood tests to rule out other conditions
• A lumbar puncture (spinal tap) to check fluid around your brain and spinal cord for signs of MS

There is no cure for MS, but treatment can help manage symptoms and slow the disease. Treatments may include:

• Disease-modifying medicines. These help slow MS and reduce relapses. They may be taken as pills, injections, or infusions.
• Medicines for symptoms, such as muscle stiffness or pain.
• Physical and occupational therapy help with movement, strength, and daily activities.

Living with MS can affect how you feel emotionally. To help you cope with these changes, try to reduce stress, connect with supportive people, eat healthy foods, and stay as active as you comfortably can.

NIH: National Institute of Neurological Disorders and Stroke

Your spinal cord is a bundle of nerves that runs down the middle of your back. It carries signals back and forth between your body and your brain. A spinal cord injury disrupts the signals. Spinal cord injuries usually begin with a blow that fractures (breaks) or dislocates your vertebrae, the bone disks that make up your spine. Most injuries don't cut through your spinal cord. Instead, they cause damage when pieces of vertebrae tear into cord tissue or press down on the nerve parts that carry signals.

Spinal cord injuries can be complete or incomplete. With a complete spinal cord injury, the cord can't send signals below the level of the injury. As a result, you are paralyzed below the injury. With an incomplete injury, you have some movement and sensation below the injury.

A spinal cord injury is a medical emergency. Immediate treatment can reduce long-term effects. Treatments may include medicines, braces or traction to stabilize the spine, and surgery. Later treatment usually includes medicines and rehabilitation therapy. Mobility aids and assistive devices may help you to get around and do some daily tasks.

NIH: National Institute of Neurological Disorders and Stroke