TERMINOLOGY

• Myelitis
• Focal Myelitis
• Transverse Myelitis
• Spina cord inflammation

INTRODUCTION

Myelitis refers to a disorder associated with acute or chronic inflammation which occurs within the spinal cord and compromises the function of nerve fibers within the gray and/or the white matter of the spinal cord. The specific cause of myelitis is not always known at the time of the initial clinical presentation. Myelitis usually involves a specific region or segment of the spinal cord. It may extend all the way across the spinal cord at the involved segment, a condition referred to as transverse myelitis. If it does not involve the whole segment of the spinal cord it may be referred to as focal myelitis or incomplete transverse myelitis.

Transverse myelitis is characterized by the development of inflammation across both sides of one level, or segment, of the spinal cord. The segment of the spinal cord at which the damage occurs determines which parts of the body are affected.  Damage at one segment will affect function at that segment and segments below it. In people with transverse myelitis, inflammation usually occurs at the thoracic (upper back) level, causing problems with leg movement and bowel and bladder control, which require signals from the lower segments of the spinal cord.  Transverse myelitis can occur anywhere along the course of the spinal cord.

PREVALENCE

Transverse myelitis occurs in adults and children, in both genders, and in all races. No familial predisposition is apparent. A peak in incidence rates (the number of new cases per year) appears to occur between 10 and 19 years and 30 and 39 years. Although only a few studies have examined incidence rates, it is estimated that about 1,400 new cases of transverse myelitis are diagnosed each year in the United States, and approximately 33,000 Americans have some type of disability resulting from the disorder.