By far the commonest demyelinating disease of the central nervous system (brain and spinal cord) is Multiple sclerosis (MS).
It is a potentially disabling disease in which the immune system attacks the protective sheath (myelin) that covers nerve fibers and causes communication problems between areas of the brain and / or the spinal cord. Eventually, the disease can cause permanent damage or deterioration of the nerve fibers.
Signs and symptoms of MS vary widely and depend on the amount of nerve damage and which areas are affected. Some people with severe MS may lose the ability to walk independently or at all, while others may experience long periods of remission without any new symptoms.
There's no cure for multiple sclerosis. However, treatments can help speed recovery from attacks, modify the course of the disease and manage symptoms.
There are other causes of central nervous system demyelination. Accurate diagnosis is of paramount importance in order to provide optimal treatment.
Rare forms of multiple sclerosis
Rare forms of multiple sclerosis include tumefactive (or tumor-like) MS, wherein brain lesions and accompanying symptoms resemble those of a brain tumor (headache, confusion, epileptic seizures etc.). A specific subtype of tumefactive MS is Baló’s concentric sclerosis, in which lesions have a characteristic onion-like form. Pediatric MS is another rare form of MS and corresponds to around 3-5% of all MS patients, characterized by an age at onset below 18 years old.
Neuromyelitis optica
Neuromyelitis optica (Devic’s disease) is a rare autoimmune disease which affects the spinal cord and optic nerves resulting in visual loss, weakness, sensory disturbance and urinary dysfunction. It is diagnosed based on the clinical presentation and findings on magnetic resonance imaging and analysis of the cerebrospinal fluid (a fluid which surrounds the brain and spinal cord). Several patients have antibodies to a protein called aquaporin-4. Neuromyelitis optica (NMO) should be distinguished from MS, as disease-modifying therapies for MS can be ineffective or even deleterious to patients with NMO.
Therapeutic considerations
Patients with rare forms of MS or NMO should be treated by neurologists with special knowledge in neuroimmunology in expert centers with easy access to magnetic resonance imaging and specialized therapies, such as plasma exchange, as well as experience in the use of potentially toxic immunosuppressive therapies. They should also be supported by a multidisciplinary team with access to rehabilitation facilities, speech therapy and special exercise regimes.