The term demyelinating disease refers to any disease that damages the myelin sheath, a part of a nerve cell. Demyelination is often a symptom rather than a cause of a disease. Diseases that cause demyelination include multiple sclerosis, vitamin B12 deficiency, transverse myelitis, and progressive multifocal leukoencephalopathy.
Neurons, or nerve cells, are shaped like trees with a long trunk, called an axon, extending from one end. Myelin is a white fatty substance that covers and insulates the axon. Damage to the myelin sheath can make it difficult for the neuron to function. The effects of this damage depend on the location of the damaged nerve cells.
Multiple sclerosis is one demyelinating disease. During the course of this disease, the immune system eats away at the myelin sheath, which damages nerves and can interfere with the communication between the brain, spinal cord, and body. Multiple sclerosis can have a wide range of symptoms depending on where the damage to the nerves is and how severe it is.
This demyelinating disease can be very difficult to diagnose because the symptoms are so diverse. Symptoms also tend to come and go and can greatly vary in severity. There is no cure for multiple sclerosis, so treatment usually focuses on managing symptoms and slowing the course of the disease.
A vitamin B12 deficiency is another cause of a demyelinating disease. B12 is an essential vitamin found in fish, meat, and dairy. The body can store several years’ worth of B12, so a deficiency is very rare, but it does occur, especially in vegans or vegetarians. There are also people whose bodies have difficulty using vitamin B12, which can cause a deficiency. A vitamin B12 deficiency leads to many diseases and problems that are a result of demyelination.
Transverse myelitis, another demyelinating disease, is caused by inflammation of the spinal cord. This inflammation attacks the myelin sheath, damaging the spinal cord. As a result, regions below the affected area of the spinal cord may feel weakness, paralysis, or pain. Transverse myelitis can be caused by a number of infections, including infections that don’t directly target the spinal cord. It can also be caused by multiple sclerosis. This disease is typically treated with anti-inflammatory drugs and rehabilitative therapy.
A very rare demyelinating disease is progressive multifocal leukoencephalopathy. This disease damages the myelin sheath in the brain. It is caused by a very common virus called the JC virus, however, most people are not affected by it. Only people with a weakened immune system, such as people suffering from AIDS, are at a high risk for this disease.