Whats happening in the brain or spinal cord during a relapse?
In MS, relapses are caused by inflamation. This happens as cells attack nerve fibres in the brain and spinal cord. Because of the attack, fluid collects around the nerve fibres. This compresses the nerves and prevents messages getting through, or distorts them. When messages are blocked in an area that has a specific function, symptoms occur. For example, this might happen in the optic nerve (the nerve to the eye), or sensory nerves in the spinal cord. When the fluid disappears and no longer compresses the nerve fibres, then there is remission. This inflammation can also, but not always, damage myelin – the protective sheath that surrounds nerve fibres in the central nervous system. Inflammation may also damage some of the nerve fibres themselves. Recent studies have shown that nerve fibres can be damaged even in the earliest stages of MS. Once the inflammation dies down and the fluid disappears, the central nervous system can ‘remyelinate’, repairing some of the damage done to myelin.
