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Toxicity, Mercury: Differential Diagnoses & Workup

Author: David K Tan, MD, FAAEM, Director, Fellowship in Emergency Medical Services, Assistant Professor of Emergency Medicine, Division of Emergency Medicine, Barnes Jewish Hospital at Washington University School of Medicine
Coauthor(s): Michael E Mullins, MD, Assistant Professor, Department of Emergency Medicine, Washington University School of Medicine
Contributor Information and Disclosures

Updated: Jul 21, 2008

Differential Diagnoses

Schizophrenia and Other Psychoses
Substance Abuse: Cocaine
Toxicity, Hallucinogens - PCP

Other Problems to Be Considered

Stroke
Illicit drug use
Parkinson disease

Workup

Laboratory Studies

History and physical examination findings consistent with mercury poisoning are helpful, but blood, urine, and (sometimes) tissue analyses are required to confirm the diagnosis of mercury intoxication. In most laboratories, mercury quantification is not performed on a routine basis; therefore, contact the laboratory to verify the specific collection and precautionary protocols before blood and urine samples are collected.

  • Blood analysis
    • Methyl mercury concentrates in RBCs. Consequently, a direct determination of the blood mercury concentrations is essential.
    • The normal range of mercury concentrations in whole blood is 0-10 mcg/L. Early signs and symptoms may occur with concentrations greater than 35 mcg/L.
    • The severity of mercury poisoning is not always correlated with the blood concentration because of the redistribution of mercury in the tissues, specifically those of the central nervous system.
  • Urinalysis
    • The detection of mercury in the urine demonstrates that exposure has occurred; however, it does not indicate the severity of mercury poisoning.
    • Methyl mercury is primarily excreted through the feces; the urinary excretion of mercury is minimal.
    • Chelated mercury is excreted primarily through the kidneys. Therefore, urinary assays are useful in monitoring chelation therapy.

Other Tests

  • Neuropsychiatric and nerve conduction studies may be helpful.
  • Hair analysis can be performed to detect mercury, but its routine use in clinical management is controversial. Proponents state that the concentrations found in organs at autopsy are correlated with concentrations found in scalp hairs. Opponents claim that the concentrations in hair represent past exposure and also that hair can simply absorb mercury from the environment.

Histologic Findings

  • Necrosis of the proximal tubules is a common direct renal toxic effect.

More on Toxicity, Mercury

Overview: Toxicity, Mercury
Differential Diagnoses & Workup: Toxicity, Mercury
Treatment & Medication: Toxicity, Mercury
Follow-up: Toxicity, Mercury
References
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References

  1. Harada M. Minamata disease: methylmercury poisoning in Japan caused by environmental pollution. Crit Rev Toxicol. 1995;25(1):1-24. [Medline].

  2. Amin-zaki L, Majeed MA, Clarkson TW, Greenwood MR. Methylmercury poisoning in Iraqi children: clinical observations over two years. Br Med J. Mar 11 1978;1(6113):613-6. [Medline].

  3. Feng X, Li P, Qiu G, Wang S, Li G, Shang L, et al. Human exposure to methylmercury through rice intake in mercury mining areas, Guizhou province, China. Environ Sci Technol. Jan 1 2008;42(1):326-32. [Medline].

  4. Madsen KM, Lauritsen MB, Pedersen CB, et al. Thimerosal and the occurrence of autism: negative ecological evidence from Danish population-based data. Pediatrics. Sep 2003;112(3 Pt 1):604-6. [Medline]. [Full Text].

  5. Andersen AH. Experimental studies on the pharmacology of activated charcoal; III. Acta Pharmacol. 1948;4:275-84.

  6. Cercy SP, Wankmuller MM. Cognitive dysfunction associated with elemental mercury ingestion and inhalation: a case study. Appl Neuropsychol. 2008;15(1):79-91. [Medline].

  7. Davis LE, Kornfeld M, Mooney HS, et al. Methylmercury poisoning: long-term clinical, radiological, toxicological, and pathological studies of an affected family. Ann Neurol. Jun 1994;35(6):680-8. [Medline].

  8. Eisler R. Mercury hazards from gold mining to humans, plants, and animals. Rev Environ Contam Toxicol. 2004;181:139-98. [Medline].

  9. Grandjean P, Weihe P, White RF, Debes F. Cognitive performance of children prenatally exposed to "safe" levels of methylmercury. Environ Res. May 1998;77(2):165-72. [Medline].

  10. Isik S, Güler M, Oztürk S, Selmanpakoglu N. Subcutaneous metallic mercury injection: early, massive excision. Ann Plast Surg. Jun 1997;38(6):645-8. [Medline].

  11. Knobeloch LM, Ziarnik M, Anderson HA, Dodson VN. Imported seabass as a source of mercury exposure: a Wisconsin case study. Environ Health Perspect. Jun 1995;103(6):604-6. [Medline].

  12. Magos L. Three cases of methylmercury intoxication which eluded correct diagnosis. Arch Toxicol. Nov 1998;72(11):701-5. [Medline].

  13. Malm O. Gold mining as a source of mercury exposure in the Brazilian Amazon. Environ Res. May 1998;77(2):73-8. [Medline].

  14. Mayo Clinic Health Letter. Mercury in fish: concerns shouldn't dampen your appetite. 1996 Apr.

  15. 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].

  16. Sue, Young-Jin. Mercury. In: Goldfrank LR, Flomenbaum NE, Lewin NA, eds. Goldfrank's Toxicologic Emergencies. 1319-29.

  17. 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].

  18. Yotsuyanagi T, Yokoi K, Sawada Y. Facial injury by mercury from a broken thermometer. J Trauma. May 1996;40(5):847-9. [Medline].

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Further Reading

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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

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Contributor Information and Disclosures

Author

David K Tan, MD, FAAEM, Director, Fellowship in Emergency Medical Services, Assistant Professor of Emergency Medicine, Division of Emergency Medicine, Barnes Jewish Hospital at Washington University School of Medicine
David K Tan, MD, FAAEM is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and National Association of EMS Physicians
Disclosure: Nothing to disclose.

Coauthor(s)

Michael E Mullins, MD, Assistant Professor, Department of Emergency Medicine, Washington University School of Medicine
Michael E Mullins, MD is a member of the following medical societies: American Academy of Clinical Toxicology and American College of Emergency Physicians
Disclosure: Johnson & Johnson stock ownership None; Savient Pharmaceuticals stock ownership None

Medical Editor

William T Zempsky, MD, Associate Director, Assistant Professor, Department of Pediatrics, Division of Pediatric Emergency Medicine, University of Connecticut and Connecticut Children's Medical Center
William T Zempsky, MD is a member of the following medical societies: American Academy of Pediatrics
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc
Disclosure: Pfizer Inc Stock Investment from broker recommendation; Avanir Pharma Stock Investment from broker recommendation

Managing Editor

Jeffrey R Tucker, MD, Assistant Professor, Department of Pediatrics, Division of Emergency Medicine, University of Connecticut and Connecticut Children's Medical Center
Jeffrey R Tucker, MD is a member of the following medical societies: American Academy of Clinical Toxicology, American Academy of Pediatrics, and Massachusetts Medical Society
Disclosure: Merck Salary Employment

CME Editor

Daniel Rauch, MD, FAAP, Director, Pediatric Hospitalist Program, Associate Professor, Department of Pediatrics, New York University School of Medicine
Daniel Rauch, MD, FAAP is a member of the following medical societies: Ambulatory Pediatric Association, American Academy of Pediatrics, and Society of Hospital Medicine
Disclosure: Baxter Honoraria Consulting; Pfizer Honoraria Consulting

Chief Editor

Timothy E Corden, MD, Associate Professor of Pediatrics, Co-Director, Policy Core, Injury Research Center, Medical College of Wisconsin; Associate Director, PICU, Children's Hospital of Wisconsin
Timothy E Corden, MD is a member of the following medical societies: American Academy of Pediatrics, Phi Beta Kappa, Society of Critical Care Medicine, and Wisconsin Medical Society
Disclosure: Nothing to disclose.

 
 
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