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In hospital and emergency neurology, the clinical analysis of unresponsive and comatose patients becomes a practical necessity. There is an urgent need to determine the disease underlying a diminished state of consciousness and the direction in which it is evolving in order to protect the brain against irreversible damage. When called upon, the physician must therefore be prepared to implement a rapid, systematic investigation of the comatose patient and prompt action that allows little time for deliberate, leisurely investigation.

Some idea of the dimensions of the problem of coma can be obtained from published statistics. Eighty years ago, in two large municipal hospitals, it was estimated that 3 percent of all admissions to the emergency wards were for diseases that had caused coma. Alcoholism, cerebral trauma, and cerebrovascular diseases were the most common, accounting for 82 percent of the comatose patients admitted to the Boston City Hospital (Solomon and Aring). Epilepsy, drug intoxication, diabetes, and severe infections were the other major causes for admission. It is perhaps surprising to learn that contemporary figures from large city hospitals differ only slightly, with intoxication, stroke, and cranial trauma standing as the “big three” of coma-producing conditions. For example, in the series collected by Plum and Posner (Table 16-1) a majority was the result of exogenous (drug overdose) and endogenous (metabolic) intoxications and hypoxia, 25 percent of cases proved to have cerebrovascular disease, and intracranial masses—such as tumors, abscesses, and hemorrhages—made up about one-third of cases. Subarachnoid hemorrhage, meningitis, and encephalitis accounted for another 5 percent. Common in some series, although obvious and often transient, is coma that follows seizures or resuscitation from cardiac arrest.


The terms consciousness, confusion, stupor, unconsciousness, and coma have been endowed with so many different ...

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