|
Alcohol intoxication (also known as drunkenness or inebriation) is a physiological state (that may also include psychological alterations of consciousness) induced by the ingestion of ethanol (alcohol). Alcohol intoxication is the result of alcohol entering the bloodstream faster than it can be metabolized by the liver, which breaks down the ethanol into non-intoxicating byproducts. Some effects of alcohol intoxication (such as euphoria and lowered social inhibitions) are central to alcohol's desirability as a beverage and its history as one of the world's most widespread recreational drugs. Despite this widespread use and alcohol's legality in most countries, many medical sources tend to describe any level of alcohol intoxication as a form of poisoning due to ethanol's damaging effects on the body in large doses; some religions consider alcohol intoxication to be a sin while others utilize it in sacrament. Symptoms of alcohol intoxication include euphoria, flushed skin and decreased social inhibition at lower doses, with larger doses producing progressively severe impairments of balance, muscle coordination (ataxia), and decision-making ability (potentially leading to violent or erratic behavior) as well as nausea or vomiting from alcohol's disruptive effect on the semicircular canals of the inner ear and chemical irritation of the gastric mucosa. Sufficiently high levels of blood-borne alcohol will cause coma and death from the depressive effects of alcohol upon the central nervous system. == Pathophysiology == Alcohol is metabolized by a normal liver at the rate of about of spirits (roughly a typical drink-size serving of beer, wine, or spirits) every 90 minutes. An "abnormal" liver with conditions such as hepatitis, cirrhosis, gall bladder disease, and cancer are likely to result in a slower rate of metabolism. Ethanol is metabolised to acetaldehyde by alcohol dehydrogenase (ADH), which is found in many tissues, including the gastric mucosa. Acetaldehyde is metabolised to acetate by acetaldehyde dehydrogenase (ALDH), which is found predominantly in liver mitochondria. Acetate is used by the muscle cells to produce acetyl-CoA using the enzyme acetyl-CoA synthetase, and the acetyl-CoA is then used in the citric acid cycle.〔Smith, C., Marks, Allan D., Lieberman, Michael, 2005, ''Marks' Basic Medical Biochemistry: A Clinical Approach'', 2nd Edtn, Lippincott Williams & Williams, USA, p. 458〕 It takes roughly 90 minutes for a healthy liver to metabolize a single ounce, approximately one hour per standard unit. Ethanol's acute effects are due largely to its nature as a central nervous system depressant, and are dependent on blood alcohol concentrations: * 20–79 mg/dL – Impaired coordination and euphoria * 80–199 mg/dL – Binge drinking: Ataxia, poor judgement, labile mood. The National Institute on Alcohol Abuse and Alcoholism (NIAAA) defines the term "binge drinking" as a pattern of drinking that brings a person’s blood alcohol concentration (BAC) to 0.08 g/dL or above. * 200–299 mg/dL – Marked ataxia, slurred speech, poor judgement, labile mood, nausea and vomiting * 300–399 mg/dL – Stage 1 anaesthesia, memory lapse, labile mood * 400+ mg/dL – Respiratory failure, coma As drinking increases, people become sleepy, or fall into a stupor. After a very high level of consumption, the respiratory system becomes depressed and the person will stop breathing. Comatose patients may aspirate their vomit (resulting in vomitus in the lungs, which may cause "drowning" and later pneumonia if survived). CNS depression and impaired motor co-ordination along with poor judgement increases the likelihood of accidental injury occurring. It is estimated that about one third of alcohol-related deaths are due to accidents (32%), and another 14% are from intentional injury.〔The World Health Organisation (2007) Alcohol and Injury in Emergency Departments〕 In addition to respiratory failure and accidents caused by effects on the central nervous system, alcohol causes significant metabolic derangements. Hypoglycaemia occurs due to ethanol's inhibition of gluconeogenesis, especially in children, and may cause lactic acidosis, ketoacidosis, and acute renal failure. Metabolic acidosis is compounded by respiratory failure. Patients may also present with hypothermia. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Alcohol intoxication」の詳細全文を読む スポンサード リンク
|