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Thallium

As Be Cd Cr Co Cu F Pb Hg Ni Tl

When ingested, thallium is a systemic poison that can produce multiple organ toxicity involving the gastrointestinal, neurologic, and cardiovascular systems. Among the distinctive effects of thallium poisoning are hair loss and painful, usually ascending, peripheral neuropathy such as extreme pain, paresthesia, and weakness in distal extremities. In 1973, the Wprld Health Organization recommended that thallium sulfate use as a rodenticide be discontinued because of its toxicity, and use in the United States for this purpose has been banned since 1975. Approximately 60 to 70% of thallium production is nowadays used in the electronics industry, with the remainder being used in manufacturing pharmaceuticals and glass.  (reference)

Prussian blue, a pigment discovered in the 1700s, is often used as a sequestering agent for certain heavy metal ions and as an antidote to thallium poisoning. In 2003, the U.S. Food and Drug Administration approved the use of Prussian blue in 500 mg capsules as safe and effective for treatment of known or suspected internal contamination with thallium (radioactive or nonradioactive) or radioactive cesium.

Deliberate contamination of food during production and preparation is rare, but instances of intentional thallium poisoning have been reported. Differences in clinical findings and case-fatality rates might be related to dosing and timing of ingestion, vehicles used, such as soft drinks, marzipan candy, and coffee, or formulation of the poisons.

Multiple government agencies and private sector health-care providers assisted and worked with each other, within and between countries, during the response to this incident. Such coordination and cooperation is critical for immediate, effective response to such events, whether they arise from unintentional or intentional circumstances. The sudden appearance of the characteristic signs and symptoms of hair loss and painful peripheral neuropathy in patients should prompt clinical consideration of thallium poisoning. Because of historical precedents, investigation should include assessment for criminal intent.  

Toxic Elements: Arsenic, Beryllium, Cadmium, Chromium, Cobalt, Copper, Fluorine, Lead, Mercury, Nickel, Thallium

References

1. Saddique A, Peterson CD. Thallium poisoning: a review. Vet Hum Toxicol 1983;25:16--22.
2. National Library of Medicine. Hazardous Substances Data Bank. Thallium, elemental. Toxnet. Bethesda, MD: US National Library of Medicine; 2008. Available at http://toxnet.nlm.nih.gov.
3. Mercurio Zappala M, Hoffman RS. Thallium. In: Flomenbaum NE, Goldfrank LR, Hoffman RS, Howland MA, Lewin NA, Nelson LS, eds. Goldfrank's toxicologic emergencies. 8th ed. New York, NY: McGraw-Hill; 2006:1364.
4. World Health Organization. Safe use of pesticides: 20th report of WHO expert committee on insecticides. WHO Tech Rep Ser 1973;513:40.
5. Lide DR, ed. CRC handbook of chemistry and physics. 76th ed. Boca Raton, FL: CRC Press Inc.; 1995--1996.
6. Torok TJ, Tauxe RV, Wise RP, et al. A large community outbreak of salmonellosis caused by intentional contamination of restaurant salad bars. JAMA 1997;278:389--95.
7. Kolavec SA, Kimura A, Simons SL, Slutsker L, Barth S, Haley CE. An outbreak of Shigella dysenteriae type 2 among laboratory workers due to intentional food contamination. JAMA 1997;278:396--8.
8. Desenclos JC, Wilder MH, Coppenger GW, et al. Thallium poisoning: an outbreak in Florida, 1988. South Med J 1992;85:1203--6.
9. Meggs WJ, Hoffman RS, Shih RD, Weisman RS, Goldfrank LR. Thallium poisoning from maliciously contaminated food. J Toxicol Clin Toxicol 1994;32:723--30.
10. Rusyniak DE, Furbee RB, Kirk MA. Thallium and arsenic poisoning in a small midwestern town. Ann Emerg Med 2002;39:307--11.

Thallium poisoning: an outbreak in Florida

In October 1988, five of seven members of a Florida family were poisoned with thallium, constituting the largest outbreak of acute thallium poisoning in the United States since thallium was banned as a rodenticide in 1972. Three patients had an acute severe neuropathy with respiratory depression; one died. The other two had no symptoms. No cases were identified among nonhousehold relatives or friends, or in the community. Of the more than 100 environmental specimens collected at the family household and tested by atomic spectroscopy, three empty and four unopened glass soft drink bottles of the same lot number yielded thallium in a concentration fatal to humans. All family members who consumed the soft drink were poisoned (5/5) as compared with none of those who did not (0/2). Because poisoning was clustered to the family and police investigators provided evidence that the poisoning was deliberately targeted to the family, it was assumed that no other soft drink bottles contained thallium, and it was decided not to recall all soft drink bottles with the same lot number. A year later a neighbor of the family was arrested and convicted of the murder.