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Toxicity, Mercury: Treatment & Medication
Updated: Jul 21, 2008
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
Treatment
Medical Care
The general management measures in Minamata disease are the same as in those of any other toxicologic exposure. After initial assessment and stabilization of the patient's condition, eliminate the patient's exposure to the source of the mercury. Provide general supportive measures, including monitoring, the performance of baseline laboratory studies, and the creation of a differential diagnosis.
Once the neurologic consequences of Minamata disease appear, they are, unfortunately, irreversible. The goal of medical management in Minamata disease is to reduce the total body burden of mercury and minimize further damage.
- Because mercury binds to the body's ubiquitous cellular sulfhydryl groups, chelating agents should be administered early in treatment. These agents are thought to competitively bind the mercury by using its thiol groups. Currently, the best agent for the treatment of Minamata disease is 2,3-dimercaptosuccinic acid (DMSA). Its toxicity is low, and animal trials have shown that it is superior to older chelating agents such as dimercaprol (BAL) and d-penicillamine (DPCN). Even in cases of inorganic mercuric salt exposure, DMSA is preferred over DPCN.
- GI decontamination may be useful only in acute recent ingestions. The absorption of organic forms of mercury, such as methyl mercury, is more than 90% in the GI tract. Inorganic mercuric salts (eg, mercuric chloride) are absorbed at a substantially lower rate of about 10%.
- Because of the high propensity for neurologic impairment, patients with acute mercury ingestion should undergo gastric lavage with solutions that contain proteins such as those from milk or egg whites.
- In addition, activated charcoal should be administered although it does not absorb heavy metals well in general. However, a 1948 in vitro study demonstrated that 1 g of activated charcoal could bind 800 mg of mercuric chloride.5
- Whole bowel irrigation, along with the administration of polyethylene glycol solution, has been shown to be useful in clearing residual mercury, as depicted on serial abdominal radiography.
- Hemodialysis is not effective in reducing the total-body mercury burden. However, acute renal failure can occur after inorganic mercuric salt ingestion, and hemodialysis may become necessary.
Surgical Care
- Surgery does not have a role in the treatment of Minamata disease; however, in other forms of mercury exposure, surgical intervention is occasionally warranted.
- Rare cases of mercury implantation into the soft tissue either accidentally or in suicide attempts are reported. In all such cases, early definitive surgical excisions of the mercury deposits result in good outcomes with minimal toxicity.
Consultations
- Clinical toxicologists are available for consultation through many regional poison control centers.
- Consultation with a toxicologist is advised in any patient in whom a significant toxicologic exposure to mercury or any other toxin is suspected.
Diet
- In some studies, the levels of mercury in shark, swordfish, and large tuna steaks exceeded the Food and Drug Administration (FDA) safety limit of 1 part per million; however, most other fish sold in the United States have clearly lower levels of approximately 0.3 part per million.
- Because of the high morbidity and mortality rates associated with methyl mercury poisoning, especially in utero, pregnant women and nursing mothers should avoid consuming larger fish because their mercury concentrations tend to be higher than those in smaller fish.
Medication
Chelating agents
These are administered early in treatment because mercury binds to the body's ubiquitous sulfhydryl groups. These agents are thought to compete with sulfhydryl groups in binding methyl mercury by using its thiol groups. Chelation has been used to increase the elimination of mercury; however, its effectiveness in preventing or treating neurologic toxicity has not been well evaluated.
Succimer (Chemet)
DMSA, metal chelator, and analog of dimercaprol. Best currently available agent for the treatment of Minamata disease. Has low toxicity. In animal trials, superior to older chelating agents.
Adult
10 mg/kg PO tid for 5 d
Pediatric
Administer as in adults
Do not administer concomitantly with edetate calcium disodium or penicillamine
Documented hypersensitivity
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in renal or hepatic impairment; prevent toxicity with adequate hydration
Dimercaprol (BAL)
Mixed in a peanut oil base. Excreted in urine and bile. May be given to patients with renal failure.
Adult
5 mg/kg IM once, followed by 2.5 mg/kg IM q8-12h for 1 d, then 2.5 mg/kg IM q12-24h until clinical improvement
Pediatric
Administer as in adults
Toxicity may increase when coadministered with selenium, uranium, iron, or cadmium
Documented hypersensitivity; G-6-PD deficiency; concurrent iron supplementation therapy
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
May be nephrotoxic; may cause hypertension; caution in oliguria or G-6-PD deficiency; may induce hemolysis in G-6-PD deficiency
Gastrointestinal decontaminants
These agents are empirically used to minimize systemic absorption of the toxin. They may be of benefit only if they are administered within 1-2 h of ingestion.
Activated charcoal (Actidose-Aqua, Liqui-Char)
Network of pores adsorbs 100-1000 mg of drug per gram of charcoal. Does not dissolve in water.
Adult
50-100 g PO
Pediatric
Infants: 1 g/kg PO
Children: 2 g/kg PO
May inactivate ipecac syrup if used concomitantly; decreases effectiveness of coadministered medications; do not mix with sherbet, milk, or ice cream (decreases adsorptive properties)
Documented hypersensitivity; poisoning or mineral acid or alkali overdose
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Induce emesis before administration; after emesis with ipecac syrup, patient may not tolerate activated charcoal for 1-2 h; can administer in early stages of gastric lavage; without sorbitol, gastric lavage returns are black
Polyethylene glycol (Colovage, CoLyte, GoLYTELY, NuLytely)
Laxative with strong electrolyte and osmotic effects that has cathartic actions in GI tract.
Adult
240 mL (8 oz) PO/NG q10min to total 4 L or until rectal effluent is clear
Pediatric
25-40 mL/kg/h PO/NG for 4-10 h or until rectal effluent is clear
Reduces effectiveness and absorption of oral medications
Documented hypersensitivity; colitis, megacolon, bowel perforation, gastric retention, GI obstruction
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in ulcerative colitis and hot loop polypectomy
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References
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Mayo Clinic Health Letter. Mercury in fish: concerns shouldn't dampen your appetite. 1996 Apr.
Morgan JN, Berry MR, Graves RL. Effects of commonly used cooking practices on total mercury concentration in fish and their impact on exposure assessments. J Expo Anal Environ Epidemiol. Jan-Mar 1997;7(1):119-33. [Medline].
Sue, Young-Jin. Mercury. In: Goldfrank LR, Flomenbaum NE, Lewin NA, eds. Goldfrank's Toxicologic Emergencies. 1319-29.
Uchino M, Tanaka Y, Ando Y, Yonehara T, Hara A, Mishima I, et al. Neurologic features of chronic minamata disease (organic mercury poisoning) and incidence of complications with aging. J Environ Sci Health B. Sep 1995;30(5):699-715. [Medline].
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Further Reading
Keywords
mercury toxicity, mercury intoxication, mercury poisoning, methyl mercury intoxication, methyl mercury toxicity, methyl mercury poisoning, Minamata disease, mercurials, fish protein, autism, hearing loss, anxiety, respiratory distress, dermatitis, gastroenteritis, swordfish, shark, large tuna
