A disorder of children acquired by swallowing or inhaling lead, which is present in the environment in paint, car exhaust fumes, and air and water contaminated with industrial waste. High levels of lead in the blood result in brain, liver, and kidney damage, and lead is deposited in the bones, affecting their growth. There is mounting evidence that even low levels of lead can impair childhood development and lower IQ.
Lead poisoningClassifications and external resources
| ICD-10 | T56.0 |
|---|---|
| ICD-9 | 984.9 |
Lead poisoning is a medical condition, also known as saturnism, plumbism or painter's colic, caused by increased blood serum lead levels.
History
Lead was first mined in Asia Minor (today Turkey) about 6500 BC.
Lead toxicity was first recognized as early as 2000 BC. Gout, prevalent in affluent Rome, is thought to be the result of lead, or leaded, eating and drinking vessels. Lead sugar (lead acetate) was used to sweeten wine, and the gout that resulted from this was known as saturnine gout.
Julius Caesar's engineer, Vitruvius, who also served his successor Caesar Augustus, reported, "Water is much more wholesome from earthenware pipes than from lead pipes. For it seems to be made injurious by lead, because white lead paint is produced from it;
Chinese alchemists found that lead could be rendered harmless by soaking it in blood and firing it, when this process was repeated several times it provided a protective coat that lead could not pass.
Today, most exposure in developed countries is the result of occupational hazards, leaded paint, and leaded gasoline (which continues to be phased out in most countries).
Symptoms and effects
The symptoms of lead poisoning include neurological problems, such as reduced IQ, nausea, abdominal pain, irritability, insomnia, excess lethargy or hyperactivity, headache and, in extreme cases, seizure and coma.
In humans, lead toxicity often causes the formation of a bluish line along the gums, which is known as the "Burton's line".
A direct link between early lead exposure and extreme learning disability has been confirmed by multiple researchers and child advocacy groups.
Biological role
Lead has no known biological role in the body.
Most lead poisoning symptoms are thought to occur by interfering with an essential enzyme Delta-aminolevulinic acid dehydratase, or ALAD. Lead poisoning is sometimes mistaken for porphyria but the distinction is that lead poisoning usually causes anemia while true porphyria does not.
An article on Lead Encephalopathy on Emedicine states: "Lead also interferes with excitatory neurotransmission by glutamate, which is the transmitter at more than half the synapses in the brain and is critical for learning. The glutamate receptor thought to be associated with neuronal development and plasticity is the N-methyl-D-aspartate (NMDA) receptor, which is blocked selectively by lead.
However, a Johns Hopkins report by Tomas Guilarte stated "It has been known for some time that lead is a potent inhibitor of the NMDA receptor, a protein known to play an important role in brain development and cognition. In this study we demonstrate that lead exposure decreased the amount of NMDA receptor gene and protein in a part of the brain called the hippocampus." They found that children who had been exposed to high levels of lead in the womb were more than twice as likely to go on to develop schizophrenia.
Occurrence
Outside of occupational hazards, the majority of lead poisoning occurs in children under age twelve. The main sources of poisoning are from ingestion of lead contaminated soil (this is less of a problem in countries that no longer have leaded gasoline) and from ingestion of lead dust or chips from deteriorating lead-based paints.
Lead has also been found in drinking water. It can come from plumbing and fixtures that are either made of lead or have trace amounts of lead in them.
Lead can also be found in some imported cosmetics such as Kohl, from the Middle East, India, Pakistan, and some parts of Africa, and Surma from India. There are also risks of elevated blood lead levels caused by folk remedies like Azarcon which contains 95 percent lead and is used to "cure" empacho. For more information about less common causes of elevated blood lead levels, see footnote.
Measurement
One measure of lead in the body is the blood lead level (BLL), measured in micrograms of lead per deciliter of blood (μg/dL). However, BLL measures current exposure to lead, but lead may also be incorporated into bone from prior exposures that will not show in BLLs until this bone-lead becomes "mobilized" through pregnancy or fracture healing.
The average person has less than 10 micrograms per deciliter, or 100 parts per billion, ppb, of lead in their blood serum. People who have been exposed to an unusual amount of lead will have lead serum levels higher than 200 ppb—most clinical symptoms of lead poisoning begin at around 100 ppb.
Treatment
Although the most important part of treating lead poisoning is decreasing exposure to lead, there are some forms of chelation therapy that can be used to reduce existing BLL levels:
DMSA EDTA British anti-LewisiteAdditionally, vitamin C (ascorbic acid), is also thought to act as a weak chelating agent, and high serum levels of vitamin C have been associated with a decreased prevalence of elevated blood lead levels.
There are also homeopathic remedies that purport to cure lead poisoning. Asa Herschoff, MD claims that Alumina helps antidote and eliminate lead from the body, and can help mental confusion, memory loss, dullness, lethargy and loss of identity, as well as high blood pressure and kidney disease.
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