Unlike the brain, where small lesions may go unnoticed and even larger areas of abnormality may remain silent for long periods of time, the spinal cord seldom experiences even a small insult without resultant clinically apparent motor or sensory manifestations. Although generally subject to many of the same disease categories as the brain, the spinal cord, because of the distinctive features and sometimes unique pathology of its afflictions, warrants its own issue of CONTINUUM. This edition, edited by Dr Dean Wingerchuk, also contains reviews of disorders of the spinal roots and the less common, but important, plexopathies.
Among those diseases affecting the spinal cord, perhaps none is more dramatic than acute transverse myelitis. Dr Benjamin Greenberg provides an update on this inflammatory disorder with an emphasis on treatment modalities. In a subsequent article, Drs Sean Pittock, Vanda Lennon, and Eoin Flanagan review autoimmune myelopathies, which often manifest as acute myelitis. This article focuses on the recent advances in understanding the role of antibody to aquaporin-4 water channels in neuromyelitis optica and related disorders. Other less common but fascinating autoimmune myelopathies, such as paraneoplastic conditions, are also discussed. Infections of the spinal cord are often considered along with the presumably immunologically mediated disorders encompassed in the articles just mentioned. These can be caused by a variety of microorganisms, including viruses, bacteria, and parasites. Of course, any article devoted to infectious myelopathies will prominently feature discussion of retroviral infections, HIV, and human T-cell lymphotropic virus types I and II. In his article, Dr Joseph Berger not only pays ample attention to these illnesses, but he also provides a guide to the myelopathies associated with a variety of other pathogens.
Not all disorders of the spinal cord are confined exclusively to that structure. Sometimes both the spinal cord and peripheral nerves are affected by the same pathologic process, resulting in a syndrome known as myeloneuropathy. Dr Brent Goodman reviews this subject, providing a diagnostic approach to the entity. Many of the causes of myelopathy also may produce myeloneuropathy; hence, this article includes further discussion of some of the same etiologic entities described elsewhere in this issue. However, toxic-metabolic disturbances particularly cause this syndrome and thus constitute a major focus of the article.
The incredibly rapid advances in the understanding of genetic disorders have not bypassed the spinal cord. While these disorders may be less frequently encountered than some of the other illnesses discussed in this issue of CONTINUUM, they are nonetheless important to recognize and understand. You will feel much more comfortable with your grasp of these disorders after reading the article on hereditary myelopathies by Dr Peter Hedera.
Having recognized the existence of transverse myelitis, you must immediately begin the process of facilitating the patient's rehabilitation. Reflecting the multidisciplinary approach needed for these patients, Dr Cristina Sadowsky leads a team of authors, including physicians Daniel Becker, Glendaliz Bosques, John McDonald, Albert Recio, and Elliot Frohman and nurse practitioner Janet Dean, in reviewing this important subject.
The next article in this issue moves away from the spinal cord itself. Dr Devon Rubin reviews both the acute and chronic polyradiculopathies, also known as polyradiculoneuropathies. Of course, the article concentrates on the entities of acute inflammatory demyelinating polyradiculopathy (Guillain-Barré syndrome) and chronic inflammatory demyelinating polyradiculopathy, but Dr Rubin also discusses other etiologies for these syndromes.
Metastatic spinal cord compression is common and generally well understood. Therefore, Dr Kurt Jaeckle has chosen instead to focus his article on metastases to the spinal cord itself, as well as to the spinal roots and plexuses.
Requests for termination of care commonly pose ethical dilemmas. These may be especially distressing in the situation of spinal cord injury or illness and have been the subject of such dramas as Whose Life Is It Anyway by British playwright Brian Clark. Dr James Gordon provides a thoughtful approach to this subject in the Ethical Perspectives section.
The issue of driving cessation is frequently considered for patients with dementia. However, the question of whether a patient can drive safely may also arise in individuals with myelopathy because of their motor or sensory impairments. In the Practice section of this issue, occupational therapist Patricia Niewoehner and Dr Florian Thomas discuss this difficult problem. Additionally, Drs Carmela Tardo and Laura Powers provide a list of useful diagnosis codes for use with spinal cord, root, and plexus disorders.
As usual, after completing your reading of CONTINUUM, you will have multiple opportunities to test your clinical understanding of the subject matter. The Patient Management Problem, crafted by Dr Rubin, will allow you to work through a case as the information unfolds and will also offer you the opportunity to earn additional CME credits. The Multiple-Choice Questions, prepared for this issue by Drs Julie Hammack and Eduardo Benarroch, also emphasize clinical mini-vignettes.
After you have read this issue of CONTINUUM, I'm sure you will agree that Dr Wingerchuk and his fellow contributors have done a masterful job of updating the subject of spinal cord, root, and plexus disorders. They have provided abundant new information while reviewing what has previously been well established for the nosologic entities in this subject area. You will undoubtedly feel much more confident as you approach patients with these difficult problems.
-Aaron E. Miller, MD