The
recent discovery of unacceptably high levels of lead in toys
being sold in the United States has focused the media spotlight
directly on the issue of lead poisoning during the past year.
Physicians, who have been focused on the issue of lead poisoning
for decades, were also disappointed by the fact that many
of our children's toys have been found to be tainted with
lead. With parents clamoring for more information on how to
prevent lead poisoning in their children, this is the perfect
time to educate the public on the dangers of this toxin.
Lead
is a naturally occurring element in our environment. In an
ideal world, the lead level in our blood would be immeasurably
low. The rise of industrialization in the United States, which
began in the late 19th century, had the negative consequence
of increasing the level of lead present in our environment.
The toxin may be found in a broad range of items including
lead-soldered cans, lead-soldered plumbing, herbal and folk
medications and imported toys. The two most common sources
of lead in today's environment are (1) paint chips or dust
from deteriorating lead paint and (2) lead residues present
in dirt along industrial thoroughfares from the combustion
of lead-containing gasoline. With these two sources in mind,
federal legislation was passed in the late 1970s to ban the
use of lead-containing paint and lead-containing gasoline
in the United States. These legislative measures have led
to a dramatic decrease in the mean blood lead level of children
less than five years of age from 16 micrograms/deciliter in
the late 1970s to a present-day mean BLL of 3 micrograms/deciliter,
a decrease of approximately 80% over three decades.
It
is estimated that roughly 300,000 children are currently at
high-risk of exposure to harmful lead levels. These children
tend to live in homes that were built before 1978 (the year
that lead paint was banned), particularly those older homes
that have been neglected. These dilapidated homes often have
paint that is peeling and chipping from walls and windowsills.
Children at high-risk of lead poisoning also tend to live
in older industrial neighborhoods, where lead dust is present
in the dirt in which children play. Children 5 years of age
and younger are more likely to have elevated blood lead levels.
They tend to spend more time crawling and tend to engage in
more hand-to-mouth behavior with household objects. This leads
to an increased likelihood of ingestion lead-containing dust
and paint chips, as these chips are reportedly chewy and have
a sweet taste.
The
signs and symptoms of lead poisoning vary greatly; with the
majority of children with elevated blood lead levels are asymptomatic.
Young children tend to have a blood-brain barrier that allows
lead to pass into brain tissue. At greatly elevated blood
lead levels, children may experience symptoms such as headaches,
clumsiness, clumsiness, malaise, and even convulsions. Developmental
delays may also be noted. The child's gastrointestinal system
may be affected, causing symptoms such as vomiting, abdominal
pain, and constipation. Anemia (low hemoglobin level) is also
a common finding in those affected by lead toxicity. Patients
with lead poisoning who are symptomatic usually have very
high blood lead levels and must be treated by a toxicologist
at a major children's hospital emergently. However, because
the damaging effects of lead on the child's brain and nervous
system are irreversible, it is preferable to detect lead toxicity
before the child's blood lead levels become greatly elevated.
Lead
toxicity is diagnosed by simply sending a blood sample to
the laboratory and determining the lead level present in the
blood. Any blood lead level greater than 10 micrograms/deciliter
is considered toxic. Given the fact that the majority of children
with lead toxicity will be asymptomatic, it is recommended
that every child have their blood lead level tested at 12
months of age and again at 24 months of age. All children
who have been adopted from a foreign country should also have
their blood lead level checked at their initial office visit,
as many countries have less stringent regulations governing
the use of lead in paints and other household products when
compared to the United States. Some pediatricians target patients
from certain zip codes or neighborhoods for screening, while
excluding children who live in newer homes and affluent suburbs.
This practice can lead to an under diagnosis of lead poisoning,
as many children may spend time at a caregiver's home that
contains lead in the environment. I would recommend screening
every child, regardless of perceived risk, by measuring a
blood lead level at least once at age 12 months. Further testing
may then occur depending upon the results of this test and
other risk factors.
Those
patients who are found to have an elevated blood level will
need to have their homes and daycare settings investigated
by the county health department. If an elevated level of lead
is found in these settings, all children should be removed
from the lead-contaminated structure until lead abatement
can be completed. Landlords who have dilapidated rental properties
containing dangerous levels of lead can be forced by the courts
to successfully remove lead from their properties. If they
fail to comply with the request of the local courts, large
fines and criminal charges may result.
Medical
treatment of severe lead poisoning (generally defined as a
lead level greater than 45 micrograms/deciliter) includes
the admission of the affected child to a children's hospital
for full evaluation and chelation. Chelation is a term that
describes the use of certain injectable medications to help
cleanse the blood of lead. This procedure should be performed
under the supervision of a pediatric toxicologist or other
physician who is skilled in providing chelation therapy. Unfortunately,
even successful chelation will not reverse the damaging neurologic
effects of lead poisoning.
Due
to the irreversible nature of the damage caused by this insidious
toxin, it behooves us to embrace the goal of creating lead-free
environments for all children in our country. We have made
great strides during the past 30 years, with the average blood
lead level in American toddlers falling dramatically due to
successful legislative efforts. Early detection of lead toxicity
via universal screening of children during toddlerhood will
be helpful. However, continued promotion of a lead-free environment
for children will hopefully eliminate the scourge of lead
poisoning from our pediatric population.
