Thallium poisoning: a review.

Thallium poisoning is one of the most complex and serious toxicities known to man. The symptomatology of its toxicity is usually nonspecific due to the multi-organ involvement. The initial symptoms of thallium poisoning may include fever, gastrointestinal problems, delirium, convulsions and coma. Symptoms may appear rapidly, but more commonly the acute toxicity subsides to be replaced by a gradual development of mild gastrointestinal disturbances, polyneuritis, encephalopathy, tachycardia, skin eruptions, stomatitis, atrophic changes of the skin, nail changes (Mee's lines), and skin hyperesthesia (mainly in the soles of the feet and the tibia). Degenerative changes of the heart, liver and kidney, subarchanoid hemorrhage, bone marrow depression, and increased radiopacity of the liver may also occur. Development of psychotic behavior with hallucinations and dementia has also been reported. In humans the most characteristic sign of thallium toxicity is alopecia which usually appears in cases when death is delayed for 15-20 days. Other signs and symptoms may develop at any stage of toxicity. The current therapy for thallium poisoning is the use of prussian blue and potassium chloride. Potassium therapy is probably the single most effective agent in the treatment of thallium poisoning. Further research, however, is needed to find an optimal antidote for thallium.