Multiple sclerosis (MS) is a disease that attacks the central nervous system, namely the spinal cord and brain. It can also affect the optic nerves, the essential nerves of vision.
“Sclerosis” means scarring or hardening, as in atherosclerosis (hardening of the arteries). In MS, the scarring occurs from damage to nerve tissue. Nerves are insulated by a fatty layer of cells known as the myelin sheath, which acts like the insulation around an electrical wire. In MS, demyelination occurs as the disease triggers the body to attack the myelin sheath as if it was a foreign invader.
As nerves more damaged and the myelin sheath deteriorates, those neurons can no longer efficiently carry signals from the brain to the organs and limbs that they control. Changes in movement and balance are common, as well as speech and other motor activities.
As certain types of MS worsen, the symptoms experienced by the patient become more severe. There is currently no cure for MS, yet various treatments can mitigate symptoms and help the person with MS live their life to the best of their ability.
Four Types of MS
There are actually four types of multiple sclerosis, each with their own course and symptomatology. According to the National Multiple Sclerosis Society, the four types of MS are:
Clinically Isolated Syndrome (CIS):
This type of MS is “a first episode of neurologic symptoms caused by inflammation and demyelination in the central nervous system. The episode, which by definition must last for at least 24 hours, is characteristic of multiple sclerosis but does not yet meet the criteria for a diagnosis of MS because people who experience a CIS may or may not go on to develop MS.”
Relapsing-remitting MS (RRMS):
This is the most common form of MS, with “clearly defined attacks of new or increasing neurologic symptoms.” Often referred to as relapses or flares, the patient may also experience periods of remission with few or no symptoms and no changes in MRI results. Approximately 85 percent of patients living with multiple sclerosis are first diagnosed with RRMS.