Mercury Poisoning

Key Features

• Acute mercury poisoning usually occurs by

  • Ingestion of inorganic mercuric salts

  • Inhalation of metallic mercury vapor

• Some organic mercury compounds (eg, dimethyl mercury) are extremely toxic by any route

• Other organic mercury compounds in fish (eg, ethyl mercury) can lead to elevated mercury levels with long-term intake

Clinical Findings

• Mercury salts

  • Metallic taste

  • Burning sensation in the throat

  • Discoloration and edema of oral mucous membranes

  • Abdominal pain

  • Vomiting

  • Bloody diarrhea

  • Shock

• Acute kidney injury from nephrotoxicity

• Inhalation of high concentrations of metallic mercury vapor may cause acute fulminant chemical pneumonia

• Chronic mercury poisoning causes

  • Weakness

  • Ataxia

  • Intention tremors

  • Irritability

  • Depression

• Exposure to alkyl (organic) mercury derivatives from highly contaminated fish or fungicides used on seeds has caused

  • Ataxia

  • Tremors

  • Convulsions

  • Catastrophic birth defects

Treatment

ACUTE POISONING

• No specific treatment exists for mercury vapor pneumonitis

• Ingestion of liquid metallic mercury: small amounts usually pass unabsorbed through the GI tract

• Treat oliguria and anuria if they occur to maintain urinary output

• For acute ingestion of mercuric salts

  • Remove ingestion by gastric lavage

  • Administer activated charcoal 60–100 g in aqueous slurry orally or via gastric tube (unproved efficacy)

  • Give dimercaprol (British anti-Lewisite, BAL) at once, 10% solution in oil, 3–5 mg/kg intramuscularly every 4–6 hours for 2 days

  • Consider succimer (DMSA), 10 mg/kg orally every 8 hours for 5 days and then every 12 hours for 2 weeks, unless patient has severe gastroenteritis

  • Unithiol (DMPS) can be given orally or parenterally but is not commonly available in the United States; it can be obtained from some compounding pharmacies

  • Contact a poison control center or medical toxicologist for assistance

CHRONIC POISONING

• Remove from exposure

• Neurologic toxicity is not considered reversible with chelation, although some recommend a trial of succimer or unithiol