Multiple sclerosis (MS) is a disease in which the immune system attacks the protective sheath (myelin) that covers the nerves. Damage to the myelin disrupts communication between the brain and the rest of the body. Eventually, the nerves may deteriorate, which is an irreversible process.
Symptoms vary relative to the amount of damage and which nerves are affected. In some cases, MS can cause a complete loss of the ability to walk while in other cases it can go into long periods of remission without causing new symptoms.
There is no cure for MS. However, treatments can help with recovery from attacks, modify the course of the disease and manage the symptoms.
Symptoms of MS can vary depending on the location of the affected nerves.
Symptoms of MS may include:
- Numbness or weakness in one or more limbs that usually occurs on one side of the body
- Partial or complete vision loss with pain during eye movement that usually affects one eye
- Double or blurred vision
- Tingling or pain
- Electric-shock sensations that occur with certain movements, especially bending the neck forward
- Tremor, lack of coordination or unsteady gait
- Slurred speech
- Bowel and bladder problems
Most cases of multiple sclerosis have a relapsing-remitting course with new symptoms that develop over time and usually improve partially or completely, followed by a remission that can last a longer period.
Up to 70% of people with relapsing-remitting MS eventually develop a progression of symptoms that may not include periods of remission (secondary-progressive MS). The rate of progression can vary among people.
The exact cause of multiple sclerosis is unclear. It is believed that it may be an autoimmune disease in which the immune system attacks its own tissues. In MS, that process destroys myelin, the substance that coats and protects nerve fibers in the brain and spinal cord.
Furthermore, a combination of factors including genetics and childhood infections can contribute to the development of multiple sclerosis in some people.
Risk factors for MS include:
- Age: The disease mostly affects people between 15 and 60 years old
- Gender: Women are more likely to develop MS
- Family history
- Certain infections such as the Epstein-Barr virus
- Race: White people of Northern European descent have a higher risk of developing MS
- Climate: MS is more common in countries with temperate climates
- Certain autoimmune diseases such as thyroid disease, type 1 diabetes or inflammatory bowel disease
Complications that may arise due to MS include:
- Muscle stiffness or spasms
- Paralysis, typically in the legs
- Problems with bladder, bowel or sexual function
- Mental changes (forgetfulness or mood swings)