α-Lipoic acid (ALA) has been shown to be protective against acute mercury poisoning in several mammalian species when it is given soon after exposure; correct dosage is required, as inappropriate dosages increase toxicity. Although it has been hypothesized that frequent low dosages of ALA may have potential as a mercury chelator, studies in rats have been contradictory. Glutathione and N-acetylcysteine (NAC) are recommended by some physicians, but have been shown to increase mercury concentrations in the kidneys and the brain.Chelation therapy can be hazardous if administered incorrectly. In August 2005, an incorrect form of EDTA (edetate disodium) used for chelation therapy resulted in hypocalcemia, causing cardiac arrest that killed a five-year-old autistic boy. Other
Experimental animal and epidemiological study findings have confirmed the interaction between selenium and methylmercury. Instead of causing a decline in neurodevelopmental outcomes, epidemiological studies have found that improved nutrient (i.e., omega-3 fatty acids, selenium, iodine, vitamin D) intakes as a result of ocean fish consumption during pregnancy improves maternal and fetal outcomes. For example, increased ocean fish consumption during pregnancy was associated with 4-6 point increases in child IQs. Prognosis
Some of the toxic effects of mercury are partially or wholly reversible provided specific therapy is able to restore selenium availability to normal before tissue damage from oxidation becomes too extensive. Autopsy findings point to a half-life of inorganic mercury in human brains of 27.4 years. Heavy or prolonged exposure can do irreversible damage, in particular in fetuses, infants, and young children.
Concerns that the prescription was having ill effects on the emperors health and sanity were waved off by the imperial alchemists, who cited medical texts listing a number of the emperors conditions (including itching, formication, swelling, and muscle weakness), today recognized as signs and symptoms of mercury poisoning, as evidence that the elixir was effectively treating the emperors latent ailments. Xuānzong became irritable and paranoid, and he seems to have ultimately died in 859 from the poisoning. The phrase mad as a hatter is likely a reference to mercury poisoning among milliners (so-called "mad hatter disease"), as mercury-based compounds were once used in the manufacture of felt hats in the 18th and 19th century. (The Mad Hatter character of Alice in Wonderland was, it is presumed, inspired by an eccentric furniture dealer named Theophilus Carter. Carter was  not a victim of mad hatter disease although Lewis Carroll would have been familiar with the phenomenon of dementia that occurred among hatters.) In 1810, two British ships, HMS Triumph and HMS Phipps, salvaged a large load of elemental mercury from a wrecked Spanish vessel near Cadiz, Spain. The bladders containing the mercury soon ruptured. The element spread about the ships in liquid and vapor forms. The sailors presented with neurologic compromises: tremor, paralysis, and excessive salivation as well as tooth loss, skin problems, and pulmonary complaints. In 1823 William Burnet, MD published a report on the effects of mercurial vapor. Triumphs surgeon, Henry Plowman, had concluded that the ailments had arisen from inhaling the mercurialized atmosphere.