Cause:Inhalation of inorganic Hg or vaporized Hg; ingestion of Hg, inorganic mercuric/ous ions or salts, or organic mercurials (eg, methyl, alkyl)
Inorganic: In miners, hatters, mirror makers, mercury factory or lab workers
Organic: Fish are major converters to methyl Hg when exposed to inorganic Hg, eg, in Minamata Bay; mercurial fungicides; low levels found in all fish may not impair childhood development (Jama 1998;280:701 vs 737). Organic Hg preservatives in interior latex paint, now removed (Nejm 1990;323:1096)
No measurable injury from amalgam Hg dental fillings even in children by RCTs (Jama 2006;295:1775, 1784, 1835)
Sx:
Hg vapor inhalation: acutely chemical pneumonitis, gingivostomatitis, noncardiac pulmonary edema; chronically neuropsych sx, tremor, acrodynia
Inorganic salt ingestion: gradual onset (mos-yrs) abdominal pain, gi bleeding, nausea, vomiting, diarrhea, shock, renal failure, CNS toxicity including erethism (shyness, decreased attention, decreased memory, decreased intellect)
Organic (see case report of fatal minor spill exposure of Dartmouth chemistry prof—Nejm 1998;338:1672): Rapid onset (day-mo), dysarthria, ataxia, leg cramps, restricted visual fields, muscle weakness, personality changes, desquamative rash, occasional gastroenteritis
Si:Inorganic: Fine tremor of face and tongue, may progress to coarse
Lab:
Chem:for elemental and inorganic exposures: whole blood urine levels followed by 24-h urine collection for Hg (>100-200 µg/L significant) and creatinine
Organic: blood Hg; urine as above; and hair analysis, but commercial lab heavy metal results unreliable (Jama 2001;285:67)
Xray:Head CT may show brain atrophy in chronic exposure
Rx:
of elemental: succimer may help
of inorganic: BAL until enteritis resolves, the succimer
of organic: succimer, possibly vitamin E as an antioxidant