Multiple sclerosis (MS) is an autoimmune demyelinating disease: the insulating cover of nerve cells in the brain and spinal cord (myelin) is attacked by the body's immune system.
There are three main types of MS:
Relapsing-remitting: isolated attacks (relapses) are followed by recovery (remission)
Secondary progressive: starting as relapsing-remitting, this type later progressively worsens without remission
Primary progressive: a steady worsening from the onset, without remissions.
Signs/symptoms are unpredictable, but can include fatigue, optic neuritis and other visual disturbance, weakness of limbs, pain, bowel and bladder problems, and sexual problems.