LEAD INTOXICATION: THE EXTENT OF PROBLEM AND ITS MANAGEMENT

Abstract

Lead is the most common heavy metal toxin and its toxic effects had been recognized for more than 2,000 years. It causes oxidative damage by disturbing the balance between prooxidants and antioxidants in favour of prooxidants. Lead is extensively used in Pakistan, because of its cost effectiveness, easy availability and resistance to corrosion. Few studies on lead intoxication have so far been conducted in Pakistan, which reveal that blood lead levels of both general population as well as of the exposed groups are much above the internationally acceptable limits (10 μg/dl). The problem of lead intoxication can be fully controlled by removing it from the industry. However, like developing countries, use of lead in industry is on rise in Pakistan, causing toxicity to both general population as well as to the factory workers. Management of cases of lead intoxication relies on removing the stored lead in the body by chelation therapy. It involves oral or parenteral administration of chelating agents that form complexes with divalent cations including lead, and enhance their excretion by kidneys. The most common chelating agents used for the management of lead intoxication are Ethylene diamaine tetraacetate (EDTA), D-penicillamine, British Anti Lewisite (BAL), Dimercapto Succinic Acid (DMSA) and Dimercapto Propane Sulfonate (DMPS). However, chelation therapy has very high incidence of side effects inclucing death. Certain antioxidant agents, especially vitamins are being investigated to know if they can minimize the toxicity of lead by reducing the oxidative stress produced by lead. The results of vitamin C supplementation during lead exposure have revealed significant improvements and therefore need further evaluation to see if it can ameliorate the toxicity of lead in conditions of unavoidable exposure.