Lead is an extremely poisonous heavy metal that can cause serious health effects in people of any age. However, lead poisoning has a more pronounced effect on growing children. Lead exposure in people of all ages is associated with a higher risk of health problems such as hypertension and kidney damage, but the main avenue for lead toxicity is through the nervous system.
The central nervous system of children is still rapidly developing, so they are more susceptible to the toxic effects of lead. In children, exposure to high levels of environmental lead can cause permanent brain damage and associated developmental problems. Acute poisoning with high levels of lead can cause seizures and coma, and can be fatal because of its effect on the nervous system. Exposure to lower levels of lead over time can lead to a higher risk of developing learning disorders, attention deficit disorder, a lower IQ and impaired hearing, along with other problems. In adults, lead poisoning can lead to cognitive difficulties and memory problems.
Lead poisoning also affects the peripheral nervous system. This disrupts how the brain interacts with the rest of the body. Lead poisoning can cause muscle weakness and loss of sensation due to nerve damage. Pain, tingling and numbness in the limbs are symptoms of peripheral nerve damage.
It is not known exactly how lead affects the nervous system, but there may be multiple ways in which it has a toxic effect. Lead can disrupt the function of neurotransmitters in the nervous system, impairing the communication between neurons. Lead may also impair calcium transport, which has a negative effect on cellular process in the nervous system and elsewhere in the body. It also disrupts the synthesis of heme groups, which are a part of the hemoglobin molecule that carries oxygen in red blood cells and in other enzymes in the body. There may also be other reasons for the negative effects of lead on various systems of the body.
It is important to reduce the exposure of children to environmental lead. Lead used to be a component of most house paint and gasoline, but it was banned in the United States. Lead exposure can still occur through paint in old houses or imported toys that have lead in the metal or paint.