ESSENTIALS OF DIAGNOSIS
Psychic and physical dependence
Intoxication and withdrawal
Medical and neurologic complications
Definitions of alcoholism vary. At its broadest, the term includes any kind of “problem drinking” (ie, applying not only to persons who are psychically or physically dependent on ethanol but also to those who, even if abstinent most of the time, get into trouble when they drink). In addition to dependence per se, neurologic problems associated with ethanol include intoxication, withdrawal, and an array of specific neurologic disorders.
In the United States, 7% of all adults and 19% of adolescents are problem drinkers. Ethanol-related deaths exceed 100,000 each year, accounting for 5% of mortality in the United States.
Ethanol affects many central nervous system (CNS) neurotransmitters, but its most important pharmacologic action is to inhibit glutamatergic excitatory transmission and to facilitate GABAergic inhibitory transmission. These effects probably contribute to the clinical features of intoxication, withdrawal, and long-term toxicity.
ESSENTIALS OF DIAGNOSIS
Stupor or coma
Acute ethanol poisoning causes more than 1000 deaths per year in the United States. An additional 2500 deaths are attributable to ethanol taken with other drugs, usually sedatives.
Ethanol is a CNS depressant, and early symptoms of intoxication often reflect cerebral disinhibition rather than stimulation. A number of factors influence the severity of intoxication, including the setting and the degree of a subject’s tolerance, and the correlations of Table 33–1 are broad generalizations. A blood ethanol concentration (BEC) of 500 mg/dL would be fatal in 50% of individuals. Death comes from respiratory depression.
Table 33–1.Blood ethanol concentration and symptoms. ||Download (.pdf) Table 33–1. Blood ethanol concentration and symptoms.
|Blood Ethanol Concentration (mg/dL) ||Symptoms |
|50–150 ||Euphoria or dysphoria; disinhibition; impaired concentration and judgment |
|150–250 ||Slurred speech, ataxic gait, diplopia, nausea, tachycardia, drowsiness, labile mood |
|300 ||Stupor alternating with combativeness, heavy breathing, vomiting |
|400 ||Coma |
|500 ||Respiratory depression, death |
The term pathologic intoxication refers to sudden excitement with irrational or violent behavior, sometimes with delusions and hallucinations, after even small doses of ethanol. Episodes last minutes or hours, and on awakening the subject is amnestic for what happened. The term alcoholic blackout refers to amnesia for periods of intoxication during which the subject appears fully conscious.
Stupor or coma in an alcoholic is too often dismissed as intoxication without consideration of potentially life-threatening alternatives. These include cerebral trauma, meningitis, hemorrhagic stroke, hypoglycemia, Wernicke encephalopathy, seizures, hepatic encephalopathy, and concomitant drug use.