Multiple sclerosis (MS) is a disease of the central nervous system (your brain and your spinal cord).
The central nervous system cells are covered in a protective layer of fatty protein called the myelin sheath (a bit like the insulation on an electrical cable). MS is an auto-immune disease, where the immune system gets confused and instead of attacking an infection or virus, the immune system turns on itself and attacks the nerve cells, damaging this protective sheath. This process is called demyelination. The demyelination disrupts the ‘messages’ being transmitted from and to the brain, causing them to slow down, become distorted or not get through at all.
The term ‘sclerosis’ means scarring. Demyelination causes many scars or lesions in different places within the central nervous system. The symptoms that occur depend on the site and severity of the lesions and this is why people with MS experience different symptoms at different times.
Approximately 100,000 people in the UK have multiple sclerosis and there are roughly three times as many women with MS as men. MS is usually diagnosed between the ages of 20 and 40. Children and older adults can develop MS but this is less common.