Book Review

Metabolic Brain Dysfunction in Systemic Disorders

N Engl J Med 1993; 328:1858June 24, 1993

Article

Metabolic Brain Dysfunction in Systemic Disorders
Edited by Allen I. Arieff and Robert C. Griggs. 477 pp., illustrated. Boston, Little, Brown, 1992. $115. ISBN: 0-316-05067-9

Optimal brain function requires a stable metabolic environment. Extracerebral systems provide the necessary nutrients, remove metabolic products, and protect the brain from sudden metabolic perturbations. It is not surprising, therefore, that conditions such as liver or kidney failure, the ingestion of toxic substances, or the presence of inherited or acquired metabolic disorders frequently results in brain dysfunction and encephalopathy. Arieff and Griggs (an internist and neurologist, respectively), both of whom have a longstanding interest in disorders of the nervous system, have invited an international group of specialists to contribute chapters as an aid to physicians from both internal medicine and neurology in the diagnosis and treatment of medical conditions that can adversely affect the nervous system.

An introductory chapter, by the editors themselves, appropriately deals with neurologic diagnosis in patients who have metabolic encephalopathy as well as with general aspects of brain metabolism, the function of the blood-brain barrier, and acid-base regulation in the central nervous system. Prognosis and factors influencing prognosis are covered coherently by Levy in chapter 2, which concludes by highlighting areas for future investigation. The chapters that follow describe in detail the deleterious effects on brain function of hypoxia, ischemia, hyponatremia, and hypernatremia, as well as hypophosphatemia, hypothermia, and hyperthermia. In each case, systemic disorders associated with these conditions are described and approaches to their diagnosis and treatment are summarized.

The potentially disastrous effects of systemic disease on brain function are clearly illustrated in four well-written chapters dealing with the central nervous system dysfunction that accompanies complications of diabetes (both hyperglycemia and hypoglycemia), liver disease, and kidney failure. In these chapters, the current understanding of pathogenetic mechanisms and the treatment of associated metabolic encephalopathies are discussed in a clear and concise manner. A discussion of neurologic abnormalities associated with endocrine disorders by one of the editors deals with pathogenetic and therapeutic aspects of adrenal, thyroid, and gonadal dysfunction. The neurologic manifestations of immunologically mediated disease are described in a separate chapter (by Giang and Schiffer), with systemic lupus erythematosus as a model.

Recent years have witnessed an exponential increase in the number of reports of neurologic complications of the acquired immunodeficiency syndrome (AIDS). Complications such as viral infections of the central nervous system (caused by both the human immunodeficiency virus and other viruses), including AIDS-dementia complex, nonviral opportunistic infections, cancers, and disorders involving the spinal cord and peripheral nerves, are described in a chapter by Wachter. Other viral infections of the nervous system, including those due to slow viruses, are described in a chapter by Greenlee. Three chapters are devoted to central nervous system disorders commonly encountered in the oncology clinic. In a well-written chapter on the neurologic complications of chemotherapeutic agents, Dawson describes syndromes such as diffuse necrotizing encephalopathy, acute cerebellar ataxia, and peripheral neuropathy. Other chapters describe both acute and delayed central nervous system manifestations of radiotherapy (vascular changes and myelopathies) and paraneoplastic syndromes that commonly antedate the discovery of cancer by several months. The application of new noninvasive techniques, such as magnetic resonance imaging and positron-emission tomography, in the diagnosis of metabolic encephalopathies that accompany viral infections such as herpes simplex, as well as those encountered in neurosarcoidosis and in systemic lupus erythematosus, is discussed in the appropriate chapters.

The book ends with well-written chapters on metabolic encephalopathy resulting from the ingestion of drugs and toxins (by Benowitz) and cerebral manifestations of genetic diseases such as phenylketonuria and urea-cycle disorders (by Anderson and Rosenberg).

The book contains some repetitions and imbalances (for example, a whole chapter is devoted to hepatic encephalopathy but less than a page of text to the other major neurologic complication of alcoholism, the Wernicke-Korsakoff syndrome). It is surprising that so little space is devoted to nutritional deficiencies (in particular, vitamin deficiencies) and their central nervous system consequences. Such shortcomings are inevitable in a multiauthored monograph, but they detract little from the otherwise thorough treatment of this important and highly prevalent group of central nervous system disorders. The editors target physicians from both internal medicine and neurology. There can be no doubt that both groups will find the book of inestimable value.

Roger F. Butterworth, Ph.D.
Hopital Saint-Luc, Montreal, QC H2X 3J4, Canada