CRC CLINIC NEUROVIR PDF

Preface

Despite our increasingly detailed knowledge of the nature of viruses, improvements in hygiene, effective vaccines for many viral illnesses, and the relatively recent emergence of antiviral therapies, viral disorders of the central nervous system remain a very real threat to human populations. In some regions of sub-Saharan Africa, for example, more than one in three people have been infected with HIV, and as many as one-half of those infected will suffer from neurological disorders. In the early 1900s, mankind dreaded influenza, which unexpectedly felled millions, and feared the Parkinson-like illness referred to as von Economo's encephalitis, which arose as a consequence of a still-unknown viral infection. New viral disorders with devastating effects on the nervous system, such as HIV and Nipah virus, have been recognized.

The spread of infections today occurs rapidly across geographical and political boundaries, unlike any ever before experienced by mankind. Diseases that had been believed to be confined to isolated regions of the world are now being reported in unexpected locales, such as West Nile virus, which in a few short years has spread across the continental United States. These emerging illnesses have undoubtedly arisen as a consequence of the greater social intercourse between once-isolated communities, as predicted by Hans Zinsser in his 1934 classic Rats, Lice and History. They represent a significant threat to public health. This threat was recognized and articulated by Juvenal before the dawn of the common era: ‘‘This plague has come upon us by infection, and it will spread still further, just as in the fields the scab of one sheep or the mange of one pig destroys an entire herd'' (Satires, II.78). These emerging illnesses are superimposed on the common and uncommon endemic and epidemic viral illnesses of the central nervous system. Similarly, in this era of bioterrorism, the potential for the re-emergence of old scourges such as smallpox has arisen. Concomitant with this potential re-emergence is the risk of neurological complications arising from the re-instituted vaccination programs. Fortunately, we have greatly surpassed the era of descriptive medicine. Today, we understand the mechanisms by which viruses enter the body and the nervous system and how they replicate within cells, and we have, in many instances, developed effective means of harnessing this knowledge to halt the spread of viruses in the community or in the individual patient.

While we have made significant progress in controlling parasitic and bacterial infections, viral infections continue to dazzle mankind. The nervous system is susceptible to a large number of viral infections that manage to effectively penetrate the blood–brain barrier or bypass it by invading the peripheral nerves and then traveling to the central nervous system along the nerve trunks. Viral infections can also remain latent in nervous system tissue for extended periods of time—sometimes spanning several years—and then become activated at an opportune moment, invading distant sites within the nervous system.

The presentations of any viral disorder of the central nervous system can try the diagnostic acumen of even the most skilled and knowledgeable physician. The infectious etiology can be mistaken for any of a number of other processes, including those of autoimmune, neurodegenerative, vascular, or metabolic/toxic nature. Clinical Neurovirology is intended to assist the clinician in understanding the basic science of neurovirology and negotiate the diagnostic and therapeutic maze associated with viral CNS disorders. Although particular emphasis is placed on retroviruses, herpesviruses, and arboviruses, this book is designed to deal with a broad range of viral infections of the CNS. Additionally, the consequences of viral CNS infection, such as autoimmune demyelinating disorders and behavioral changes, are addressed. The clinical presentations (both common and uncommon), the measures that are most effective in establishing the diagnosis, and the available therapies (both established and experimental) are addressed in each chapter.

Major developments have recently occurred in the treatment of viral infections of the brain—particularly with the retroviruses, herpesviruses, and arboviruses—and several new antiviral drugs are currently under development; this book provides a detailed discussion of these new and future therapeutic approaches. We hope that this book has a broad appeal to neurologists, infectious disease specialists, internists, family practitioners, pediatricians, physicians-in-training, and all others who confront these patients.