Infectious diseases are endlessly fascinating and constantly changing. Those that affect the nervous system are no exception, so in this timely issue of Continuum Dr Christina Marra has assembled an expert faculty to review and update that subject for neurologists.
Meningitis is, of course, the most common form of nervous system infection that neurologists encounter. Fittingly, therefore, discussion of leptomeningeal infections dominates this issue. For the layperson, few other medical terms create the degree of instant terror raised by the term meningitis. Indeed, the neurologist also must respond with great urgency when that threat exists. Yet it is acute bacterial meningitis that poses the true emergency; consequently that subject is the focus of the first chapter in this issue. Dr Karen Roos discusses the differential diagnosis of acute meningitis and provides very specific recommendations for the contemporary management of bacterial meningitis. Reading this chapter should help neurologists realize the satisfaction of successfully curing a life-threatening illness, a goal we can seldom achieve with the other, often chronic, ailments we commonly manage.
Fortunately, most meningitis is not the fulminant bacterial variety. In chapter 2, Dr Larry Davis takes the reader through the lengthy differential diagnosis of subacute and chronic meningitis. The range of possibilities includes viral, mycobacterial, spirochetal, rickettsial, fungal, and parasitic diseases, as well as some noninfectious disorders. Dr Davis provides a very useful strategy for navigating through this potentially bewildering sea. In the following chapter, Drs Roberta DeBiasi and Kenneth Tyler focus on viral infections of the central nervous system (CNS). They expand the discussion of viral meningitis begun by Dr Roos but also concentrate extensively on the more serious viral encephalitides and include a brief review of the "parainfectious" acute disseminated encephalomyelitis.
The second half of this Continuum issue emphasizes infectious diseases that occur in several specific clinical settings. The number of organ transplantations is steadily rising, and the intense immunosuppression often required to maintain success brings the risk of a variety of opportunistic infections. Dr Todd Czartoski educates us on these relatively unfamiliar entities, which we will encounter with greater frequency as transplantation procedures become increasingly common. Human immunodeficiency virus (HIV) infection continues to be a devastating scourge. The advent of highly active antiretroviral therapy (HAART) has dramatically improved the prognosis for infected patients in the United States; yet HIV continues to decimate the population in many developing countries, especially in sub-Saharan Africa where more than 25 million people are infected and the number of cases continues to increase. An inability to deliver treatment to victims of acquired immune deficiency syndrome (AIDS) in these areas, even now that some inexpensive generic drugs are available, compounds this tragedy. In some countries, like South Africa, ludicrous statements, even from politicians, contending that HIV is not the cause of AIDS accentuate the horror. In her chapter, Dr Marra reviews the CNS infections complicating HIV infection, highlighting the changes that have occurred in the developed world with the use of HAART.
Widespread international travel for both business and vacation purposes now exposes many North Americans and Europeans to infectious agents endemic to other areas of the world such as Latin America, Asia, and Africa. Because of the delayed incubation period for diseases caused by many such microbes and the rapidity of air travel, Western neurologists must be attuned to the possibility of these diseases and must remember to take a travel history. In the final chapter of this issue, Drs May Han, Melanie Walker, and Joseph Zunt discuss neurological infections of international travelers, focusing on Japanese encephalitis, malaria, rabies, dengue, and neurocysticercosis.
This issue of Continuum also introduces an exciting new feature on ethical perspectives in neurological disease. Each issue will now include a brief discussion of an ethical dilemma raised by the subject, employing a case-based format. I am very pleased that Dr Michael Williams, who also serves as chairman of the American Academy of Neurology's Ethics, Law, and Humanities Committee, has agreed to spearhead this effort and will serve as Continuum's Associate Editor for Ethics. Dr James Gordon has ably collaborated with Dr Williams to provide timely and provocative commentary on a hypothetical case involving this month's topic of infectious diseases.
Finally, I urge you not to neglect the patient management problem and the multiplechoice questions. The latter have been designed, in this case by Drs Eduardo Bennaroch and Julie Hammack, to enhance and consolidate the learning experience. Read on; I believe you will find this an intriguing and exciting issue of Continuum.
Aaron E. Miller, MD