Mercury occurs in three different forms (elemental, inorganic, and organic), each with its own clinical pattern of poisoning. Elemental mercury (“quicksilver”) is found in old thermometers and sphygmomanometers. Elemental mercury poisoning is associated with inhalation of volatilized mercurial ions, which may occur after vacuuming or heating. Manifestations include cough, fevers, chills, and dyspnea. Acute interstitial pneumonitis may occur and may progress to severe lung injury and death. Inorganic mercury poisoning usually occurs from the ingestion of the mercurial salts. Initial presentation is acute caustic gastroenteritis that may be hemorrhagic. Renal failure is a prominent finding in these patients. Organic mercury poisoning occurs from ingestion of short-chain alkyl mercurial compounds. Methylmercury distributes into brain tissue and causes neurologic disease such as ataxia, paresthesias, visual difficulties, movement disorders, and speech difficulties. Methylmercury is also a known teratogen.
Subcutaneous Mercury. Lateral radiograph of an ankle demonstrating elemental mercury in the tissues. The patient had a barometer break into his skin. (Photo contributor: Saralyn R. Williams, MD.)
Management and Disposition
After an ingestion of a mercurial substance, a radiograph may demonstrate radiopaque material in the GI tract. If elemental mercury was injected intravenously, mercurial emboli may be seen in the lungs. Local injection in the skin may demonstrate mercury deposition in the soft tissues. Ingestion of elemental mercury rarely results in significant absorption. For inhalational injury due to elemental mercury, respiratory support may be required. Ingestion of inorganic mercury may lead to early cardiovascular collapse as a result of the severe volume depletion. Fluid resuscitation and electrolyte management are critical. Chelation with dimercaprol (BAL) may be initiated early, and when the patient is able to take oral medications, the chelator may be switched to succimer. For organic mercury poisoning, oral succimer is the first-line agent.
Mercurial Emboli. Appearance of mercurial emboli in the pulmonary vascular tree on chest x-ray. Although this may be seen from intentional intravenous mercury injection, this patient absorbed the mercury intravenously following an accident involving multiple shattered thermometers. (Photo contributor: John Worrell, MD.)
Mercury Salts. Mercury salts were used as topical antiseptics. Ingestion of inorganic mercury is caustic to the gastrointestinal tract and causes rapid renal failure. (Photo contributor: Matthew D. Sztajnkrycer, MD, PhD.)
Elemental mercury toxicity has occurred when it is heated and used to extract gold from jewelry.
“Mad as a hatter” is a phrase used to describe the delirium from anticholinergic poisoning; however, the phrase is derived from the erethism and hatter’s shakes from mercury exposure during the felt-hat manufacturing process in the late 19th and early 20th centuries....