Thallium

Trace elements can be essential or toxic. Trace element toxicity can occur as a result of occupational exposure, environmental exposure or iatrogenic toxicity. Any organ can be affected: the central nervous system, liver, kidneys, muscles or circulatory system. All elements can be toxic in excess. Those most commonly associated with toxicity include: aluminium, lead, arsenic, cadmium, mercury and thallium. Thallium is a colourless, odourless, tasteless salt in solution which is highly toxic. Thallium is readily absorbed through the gut, inhalation and/or contact with the skin and thus has been used as a poison. Thallium acts by disrupting the binding of potassium to the Na+/K+/ATPase. It leads to the disruption of gradient formation important for the normal activity of nerve and muscle cells. Sources of thallium include: manufacturing processes, old rodent poisons/insecticides.

Symptoms include: nausea/vomiting, incontinence, abdominal pain, pancreatic damage, muscle weakness, headaches, neurological symptoms and coma. 2-3 weeks after the initial exposure, hair loss usually occurs. Many of the subsequent symptoms may be confused with Guillain-Barré syndrome, porphyria, SLE, botulism, radiation sickness or other poisoning.