Preface

The first three editions of Harrison's Neurology in Clinical Medicine were unqualified successes. Readers responded enthusiastically to the convenient, attractive, expanded, and updated stand-alone volume, which was based upon the neurology and psychiatry sections from Harrison's Principles of Internal Medicine. Our original goal was to provide, in an easy-to-use format, full coverage of the most authoritative information available anywhere of clinically important topics in neurology and psychiatry, while retaining the focus on pathophysiology and therapy that has always been characteristic of Harrison's.

This new fourth edition of Harrison's Neurology in Clinical Medicine has been extensively updated to highlight recent advances in the understanding, diagnosis, treatment, and prevention of neurologic and psychiatric diseases. Readers will find expanded coverage of the neurodegenerative diseases, highlighting advances in their classification and management, and delineating the new understanding of mechanisms responsible for the deposition and spread of pathogenic protein aggregates in these disorders. Neuroimmunology is another dynamic and rapidly changing field of neurology, and the new edition of Harrison's provides extensive coverage of progress in this area, including a timely summary of advances in understanding paraneoplastic syndromes, autoimmune encephalitis, and neuromyelitis optica, as well as a practical guide to navigating the large number of treatment options now available for multiple sclerosis. The chapter on cerebrovascular diseases has also been extensively revised to reflect the exciting new opportunities for acute treatment and prevention of ischemic and hemorrhagic stroke. Sleep disorders and migraine are additional areas in which important advances are highlighted in the new edition. Many illustrative neuroimaging figures appear throughout the section, and an updated and expanded atlas of neuroimaging findings is also included. We have been extremely pleased with the warm reception that greeted the high-definition video presentations introduced in the last edition of Harrison's, and in the fourth edition we have added to the collection new videos illustrating sleep disorders and examination of the comatose patient.

For many physicians, neurologic diseases represent particularly challenging problems. Acquisition of the requisite clinical skills is often viewed as time-consuming, difficult to master, and requiring a working knowledge of obscure anatomic facts and laundry lists of diagnostic possibilities. The patients themselves may be difficult, as neurologic disorders often alter an individual's capacity to recount the history of an illness or to even recognize that something is wrong. An additional obstacle is the development of independent neurology services, departments, and training programs at many medical centers, reducing the exposure of trainees in internal medicine to neurologic problems. All of these forces, acting within the fast paced environment of modern medical practice, can lead to an overreliance on unfocused neuroimaging tests, suboptimal patient care, and unfortunate outcomes. Because neurologists represent less than 1% of all physicians, the vast majority of neurologic care must be delivered by nonspecialists who are often generalists and usually internists.

The old adage that neurologists “know everything but do nothing” has been rendered obsolete by advances in molecular medicine, imaging, bioengineering, and clinical research. Examples of new therapies include intravenous and endovascular recanalization in acute ischemic stroke, intensive monitoring of brain pressure and cerebral blood flow for brain injury, effective therapies for immune-mediated neurologic disorders, new designer drugs for migraine, the first generation of rational therapies for neurodegenerative diseases, neural stimulators for Parkinson's disease, drugs for narcolepsy and other sleep disorders, and control of epilepsy by surgical resection of small seizure foci precisely localized by functional imaging and electrophysiology. The pipeline continues to grow, stimulated by a quickening tempo of discoveries generating opportunities for rational design of new diagnostics, interventions, and drugs.

The founding editors of Harrison's Principles of Internal Medicine acknowledged the importance of neurology but were uncertain as to its proper role in a textbook of internal medicine. An initial plan to exclude neurology from the first edition (1950) was reversed at the eleventh hour, and a neurology section was hastily prepared by Houston Merritt. By the second edition, the section was considerably enlarged by Raymond D. Adams, whose influence on the textbook was profound. The third neurology editor, Joseph B. Martin, brilliantly led the book during the 1980s and 1990s as neurology was transformed from a largely descriptive discipline to one of the most dynamic and rapidly evolving areas of medicine. With these changes, the growth of neurology coverage in Harrison's became so pronounced that Harrison suggested the book be retitled, The Details of Neurology and Some Principles of Internal Medicine. His humorous comment, now legendary, underscores the depth of coverage of neurologic medicine in Harrison's befitting its critical role in the practice of internal medicine.

The editors are indebted to our authors, a group of internationally recognized authorities who have magnificently distilled a daunting body of information into the essential principles required to understand and manage commonly encountered neurologic problems. Thanks also to Dr. Elizabeth Robbins who has served for more than 20 years as managing editor of the neurology section of Harrison's; she has overseen the complex logistics required to produce a multiauthored textbook, and has promoted exceptional standards for clarity, language, and style. Finally, we wish to acknowledge and express our great appreciation to our colleagues at McGraw-Hill. This new volume was championed by James Shanahan and impeccably managed by Kim Davis.

We live in an electronic, wireless age. Information is downloaded rather than pulled from the shelf. Some have questioned the value of traditional books in this new era. We believe that as the volume of information, and the ways to access this information, continue to grow, the need to grasp the essential concepts of medical practice becomes even more challenging. One of our young colleagues recently remarked that he uses the Internet to find facts, but that he reads Harrison's to learn medicine. Our aim has always been to provide the reader with an integrated, organic summary of the science and the practice of medicine rather than a mere compendium of chapters, and we are delighted and humbled by the continuing and quite remarkable growth in popularity of Harrison's at a time when many “classics” in medicine seem less relevant than in years past. We are of course cognizant of the flexibility in information delivery that today's readers seek, and so we have also made the fourth edition of Harrison's Neurology in Clinical Medicine available in a number of eBook formats for all major devices, including the iPad (available via the iBookstore).

It is our sincere hope that you will enjoy using Harrison's Neurology in Clinical Medicine, Fourth Edition, as an authoritative source for the most up-to-date information in clinical neurology.