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Mercury poisoning (also known as hydrargyria or mercurialism) is a type of metal poisoning and a medical condition caused by exposure to mercury or its compounds. Mercury (chemical symbol Hg) is a heavy metal occurring in several forms. All of these, except elemental liquid mercury (for which intravenous injection of a comparable volume can be nonlethal〔) produce toxicity or death with less than a gram. Elemental mercury does cause damage by blocking blood vessels. Mercury's zero oxidation state Hg0 exists as vapor or as liquid metal, its mercurous state Hg+ exists as inorganic salts, and its mercuric state Hg2+ may form either inorganic salts or organomercury compounds; the three groups vary in effects. Toxic effects include damage to the brain, kidneys and lungs.〔 Mercury poisoning can result in several diseases, including acrodynia (pink disease),〔 Hunter-Russell syndrome, and Minamata disease.〔 Symptoms typically include sensory impairment (vision, hearing, speech), disturbed sensation and a lack of coordination. The type and degree of symptoms exhibited depend upon the individual toxin, the dose, and the method and duration of exposure. ==Signs and symptoms== Common symptoms of mercury poisoning include peripheral neuropathy, presenting as paresthesia or itching, burning, pain, or even a sensation that resembles small insects crawling on or under the skin (formication); skin discoloration (pink cheeks, fingertips and toes); swelling; and desquamation (shedding or peeling of skin). Mercury irreversibly inhibits selenium-dependent enzymes (see below) and may also inactivate S-adenosyl-methionine, which is necessary for catecholamine catabolism by catechol-o-methyl transferase. Due to the body's inability to degrade catecholamines (e.g. epinephrine), a person suffering from mercury poisoning may experience profuse sweating, tachycardia (persistently faster-than-normal heart beat), increased salivation, and hypertension (high blood pressure). Affected children may show red cheeks, nose and lips, loss of hair, teeth, and nails, transient rashes, hypotonia (muscle weakness), and increased sensitivity to light. Other symptoms may include kidney dysfunction (e.g. Fanconi syndrome) or neuropsychiatric symptoms such as emotional lability, memory impairment, and / or insomnia. Thus, the clinical presentation may resemble pheochromocytoma or Kawasaki disease. An example of desquamation (skin peeling) of the hand and foot of a child with severe mercury poisoning acquired by handling elemental mercury is (this photograph ) in Horowitz, ''et al.'' (2002). 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「Mercury poisoning」の詳細全文を読む スポンサード リンク
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