Diagnosis of Demyelinating Diseases
From The MS Information Sourcebook, produced by the National MS Society.
There are a number of conditions that are classified as demyelinating diseases. In these conditions the myelin sheath (the fatty insulation covering the nerve fibers) becomes damaged or destroyed. Once damaged, the nerves are unable to properly perform their function of conducting electrical impulses.
Demyelination in the Central Nervous System
MS is the most common demyelinating disease. It affects only the myelin of the central nervous system-the brain, optic nerves, and spinal cord. Some other causes of central nervous system demyelination are viral infections, side effects from high exposure to certain toxic materials, severe vitamin B12 deficiency, autoimmune conditions that lead to inflammation of blood vessels (the "collagen-vascular diseases"), and some rare hereditary disorders.
Demyelination Can Occur In Peripheral Nervous System
The peripheral nervous system is composed of the nerves outside the brain and spinal cord. Demyelination of the peripheral nervous system can be found in diseases such as Guillain-Barré Syndrome. After some injuries, the myelin sheath in the peripheral nervous system regenerates, bringing recovery of function.
Not All Demyelinating Conditions Are Progressive
Some demyelinating conditions are self-limiting, while others may be progressive. Careful (and sometimes repetitive) examinations may be needed to establish an exact diagnosis among the possible causes of neurologic symptoms.
For Healthcare Professionals
Kalb R. (ed.) Multiple Sclerosis: The Questions You Have; The Answers You Need (3rd ed.). New York: Demos Medical Publishing, 2004.
—Ch. 3 Neurology
Kalb R. (ed.). Multiple Sclerosis: A Guide for Families (3rd ed.). New York: Demos Medical Publishing, 2005.
—Ch. 1 When MS Joins the Family