Case Definition: Mercury (Elemental)

Clinical description

Inhalational exposure is the most typical route of elemental mercury toxicity. Acute toxicity might result in fever, fatigue, and clinical signs of pneumonitis. Chronic exposure results in neurologic, dermatologic, and renal manifestations. Signs and symptoms might include neuropsychiatric disturbances (e.g., memory loss, irritability, or depression), tremor, paresthesias, gingivostomatitis, flushing, discoloration and desquamation of the hands and feet, and hypertension (1-6).

Laboratory criteria for diagnosis

• Biologic: A case with an elevated urinary or whole blood mercury concentration. A urinary mercury concentration ≥ 10 ug/L or a total whole blood mercury concentration ≥ 10 ug/L is an unusual level of exposure for a person with no known occupational exposure to mercury. Fish consumption can elevate total whole blood mercury concentrations. (1-2)

- OR-

• Environmental: Detection of mercury in environmental samples. (7-10)

Case classification

• Suspected: A case in which a potentially exposed person is being evaluated by healthcare workers or public health officials for poisoning by a particular chemical agent, but no specific credible threat exists.
• Probable: A clinically compatible case in which a high index of suspicion (credible threat or patient history regarding location and time) exists for elemental mercury exposure, or an epidemiologic link exists between this case and a laboratory-confirmed case.
• Confirmed: A clinically compatible case in which laboratory tests have confirmed exposure.

The case can be confirmed if laboratory testing was not performed because either a predominant amount of clinical and nonspecific laboratory evidence of a particular chemical was present or the etiology of the agent is known with 100% certainty.

Additional resources

1. Sue, YJ. Chapter 96 - Mercury. In: Nelson LS, Lewin NA, Howland MA, Hoffman RS, Goldfrank LR, Flomenbaum NE, eds. Goldfrank's Toxicologic Emergencies. 9th ed. New York, NY: McGraw-Hill; 2011:1299-1307
2. Baselt RC. Disposition of Toxic Drugs and Chemicals in Man. 9th ed. Biomedical publications. Seal Beach, California, 2011.
3. CDC. Current trends acute and chronic poisoning from residential exposures to elemental mercury--Michigan, 1989-1990. MMWR 1991;40:393-5.
4. CDC. Elemental mercury poisoning in a household--Ohio, 1989. MMWR 1990;39:424-5.
5. Agency for Toxic Substances and Disease Registry. Toxicologic profile for mercury. Atlanta, GA: Agency for Toxic Substances and Disease Registry, Division of Toxicology; 1999.
6. Caravati EM, Erdman AR, Christianson G, Nelson LS, Woolf AD, Booze LL, Cobaugh DJ, Chyka PA, Scharman EJ, Manoguerra AS, Troutman WG; American Association of Poison Control Centers. Elemental mercury exposure: an evidence-based consensus guideline for out-of-hospital management. Clin Toxicol. 2008 Jan; 46 (1): 1-21.
7. NIOSH. NIOSH manual of analytical methods [online]. 2003. [cited 2013 Apr 5]. Available from URL: http://www.cdc.gov/niosh/docs/2003-154/.
8. OSHA. Sampling and analytical methods [online]. 2010. [cited 2013 Apr 5]. Available from URL: http://www.osha.gov/dts/sltc/methods/index.html.
9. FDA. Food: Laboratory methods [online]. 2013. [cited 2013 Apr 5]. Available from URL: http://www.fda.gov/Food/FoodScienceResearch/LaboratoryMethods/default.htm.
10. EPA. Selected analytical methods: chemical methods query [online]. 2013. [cited 2013 Apr 5]. Available from URL: http://www.epa.gov/sam/searchchem.htm.