Throughout our body there are a lot of sensitive nerve endings. These nerves tell us if what we touch is cold or hot, soft or hard, by sending signals to the central nervous system, which processes them and turns them into the sensations we feel when we touch something or even when we see and hear something. The nerve endings are surrounded by a protective membrane called myelin.
Also, in our bodies you can find a lot of white blood cells and antibodies. These have the role of guarding the body against infections and foreign organisms that get inside it. Both the antibodies and white blood cells are controlled by the central nervous system. When it detects an infection it sends them attack the Holsteins bacteria that cause it.

Now that we've gone through these basic facts we can understand multiple sclerosis. When a person has multiple sclerosis the central nervous is confused and it sends the white blood cells and antibodies attack the myelin that protects the nerve endings. When these attacks occur the sense which uses the involved nerve endings gets affected.
Depending on what sense is attacked the symptoms vary widely from one person to another. If it's the visual sense then temporary loss of vision can appear, or if it's not a full loss of vision the blurry or doubled vision occurs.
The motor system can also be attacked and in this case loss of balance and coordination are experienced by the person in cause.
Sometimes those with multiple sclerosis also feel confused, experience mood swings, and have respiratory problems.

The cause of these attacks is unknown, no one can tell what makes the nervous system attack the nerve endings, but scientists are researching the reason and they hope to discover it soon.

There is no treatment that can cure multiple sclerosis, and in order to find a good treatment we need to discover the cause first. Until then the treatment can only try to stop or ameliorate the attacks. There are a few drugs that have been proven to help those suffering from multiple sclerosis but nothing that does something certain against it has been released. Let's hope that research will bring good news in the near future.
You can search the Internet for more multiple sclerosis information and you can also find support groups created to help those that suffer from it and put them in touch with the latest breakthroughs in the domain.