Contemporary neurology series最新文献

The EEG in normal aging and in dementia due to a variety of diseases has been described. In dementia due to degenerative diseases, metabolic disorders, normal pressure hydrocephalus, and deficiency states, the diffuseness of the abnormalities observed has been emphasized; whereas with cerebrovascular disease and with intracranial massess, the focal nature of the changes has been stressed. Although a normal EEG does not rule out the diagnosis of dementia especially in its early stages, the EECG can nevertheless be a significant instrument in the identification or organic processes when the diagnosis is uncertain, in differentiating diffuse from focal cerebral lesions, and in following the course of the disease. Because electroencephalography is easily performed, is safe, and can be frequently repeated, it should be considered one of the more useful tools in the clinical evaluation of patients with dementia.

Leprosy is the cause of the commonest peripheral neuropathy. The predilection of Mycobacterium leprae for nerve tissue accounts for the clinical features that are most dreaded and most characteristic of the disease. Were it not for the progressive destruction of peripheral nerve trunks and the consequences of this, leprosy would largely remain a cutaneous condition of cosmetically unsightly hypopigmented or erythematous areas and aggregations of nodular thickenings. The neurologic damage in leprosy is confined to postganglionic changes. The central nervous system is protected, although rarely in experimental situations organisms have been reported in cerebral tissues.

The concept of the sea as a source of noxious agents is perhaps not a familiar one to clinical neurologists, judging by the lack of reference to these agents in standard textbooks. Chemical, physiologic, and pharmacologic laboratories are increasingly investigating the properties of marine toxins, finding in them compounds with interesting and novel structures or unusual physiologic effects. Such substances are seen as possible agents for biologic and, more particularly, physiologic research, and as possible sources of new pharmaceuticals. These include hormone-like substances and antiviral or antitumor agents. Despite these specialized developments, which are in large measure a consequence of the technological advances of the present century, the clinician is at times directly concerned with the effects of marine toxic substances. For example, in Japan, puffer fish or tetrodotoxic poisoning is one of the major causes of deaths from food poisoning. Another marine toxin that has caused many explosive outbreaks of food poisoning. with many deaths in various parts of the world, comes from clams or mussels. This toxin, saxitoxin, is produced by species of marine protozoa including Gonyaulax, and is concentrated in filter-feeding molluscs. These two examples were of significant interest in medicine long before the technologic developments of the twentieth century. In the last few decades, entirely new problems of marine intoxication have arisen as a result of marine pollution from the disposal of industrial wastes in the sea. The most striking example of a man-made marine intoxication has been the outbreak of Minamata disease. In Minamata, Japan, the disposal of mercury-contaminated industrial wastes from a plastics factory into an enclosed bay, followed by human consumption of the contaminated fishes, crabs, or shellfish, led to many instances of acute cerebral degeneration. With the increasing exploration of the sea for both pleasure and economic exploitation, which is a feature of the second half of the twentieth century, it may be expected that the frequency and variety of human intoxications by marine creatures will be increased. This chapter reviews the neurologic effects of noxious substances of marine biologic origin. The subject is now developing so rapidly that overall surveys, such as this, of the general animal life of theocens will soon be beyond the scope of a single review. Nevertheless, it is hoped that the references given will enable the interested reader to pursue particular aspects further.

Angiostrongyliasis is an infectious disease caused by nematode parasites of the genus Angiostrongylus. The rat lung worm Angiostrongylus cantonensis, primarily a parasite of rodents, is largely responsible for human cases of eosinophilic meningitis, or meningoencerphalitis, which occurs on many Pacific islands and in Southeast Asia. The disorder, which frequently occurs in epidemic extent, is caused by invasion of the central nervous system by developing larvae of the parasite. The infection is most frequently due to ingestion of food containing the infective, third-state, larvae. Meningitic and ocular forms of the disease have been recognized. The disease has been described or referred to under a variety of synonyms. The terms eosinophilic meningitis, eosinophilic meningoencephalitis, and epidemic eosinophilic meningitis were first used to describe the disease before its etiology was known. These terms, however, lack specificity, because the eosinophilic meningitic syndrome may accompany many other parasitic as well as nonparasitic diseases of the central nervous system. Nevertheless, they are still being widely used, since in most cases only the epidemiology of the disease points to the etiologic role of A. cantonensis. Direct clinical or laboratory evidence of the etiologic agent is usually not established because reliable tests are not yet available. The term angiostrongylosis, or angiostrongyliasis, if used without the adjective, also may give rise to confusion, since the same term is applied to the pulmonary infection of dogs by A. vasorum and might be used for infection by any other Angiostrongylus species. Even the term cerebral or ocular angiostrongyliasis may prove in the future to have similar disadvantages. The scientifically correct term angiostrongyliasis cantonensis has been used recently. It is sufficiently specific and formed in analogy to the names of other parasitic diseases of man, like schistosomiasis japonica, schistosomiasis mansoni, schistosomiasis haematobia. For the murine infection, as well as for the disease produced experimentally in animals, the term angiostrongylosis cantonensis ought to be reserved because of the preferential use by veterinarians of the ending osis for designation of pathological changes produced in animals by parasites. After the recent discovery of A. costaricensis, another rat parasite causing human disease in Costa Rica, it becomes necessary to distinguish between angiostrongyliasis cantonensis (eosinophilic meningitis) and angiostrongyliasis costaricensis (intra-abdominal eosinophilic granulomatosis). A potential disadvantage of these terms may be encountered in case of a systemic revision or reclassification of the parasite. This has happened at intervals. A. cantonensis was named Pulmonema cantonensis by its discoverer and later was described under the name Haemostrongylus ratti.

Kuru is a progressive, invariably fatal cerebellar degeneration which occurs in a limited area of the New Guinea Highlands. The word kuru is derived from a term in the Fore language meaning to shake from fear, and it stems from the trembling which is a conspicuous symptom. Few neurologic diseases have attracted the attention of specialists in so many disciplines. No rare disease can have aroused more interest among the laity. Apart from an extensive scientific and anthropological literature, kuru has been the source of inspiration to journalists and travel writers, and it even occupies a prominent position in the plot of a popular novel. The facts concerning kuru are no less remarkable than the mythology that has grown up around it.