Introduction
Human development is thought to follow a stepwise growth pattern. For example, motor skills, speech and weight are all quantified and observed closely during the stages of aging. However linear this process may seem there is still unpredictability that can arise during this delicate progression. For example, poisonings are a well-known pediatric problem, such as Tide Pods and acetaminophen toxicities seen yearly. Another example, has been identified by WHO as 1 of 10 chemicals of major public health concern and an environmental toxicity, lead. (2018) This is a worldwide pediatric problem due to the sequelae it can cause and the history it holds in public health contaminations of food and water.
Lead is a ubiquitous chemical element that holds no essential function in the human body. There have been strides made in the United States to eliminate exposures of lead, such as removing it from gasoline and paint. Yet, this preventable disease still has common sources that children are still exposed to that will be mentioned later.
While this toxicant is universal it is especially more harmful to young children because their absorption rates are 4 to 5 times greater compared to adults. (WHO, 2018) Lead is distributed throughout the body including the liver, brain, bones and kidneys and poses fatal threats to developing children. It can also harm the unborn child, due to mobilization of stored lead in bone during pregnancy.
Scope of the Issue
According to the American Academy of Pediatrics, there is no safe level of lead in the body and blood levels as low as 5 mcg/dL has lasting detriments in cognition, and behavioral difficulties. (2016) Children can present in numerous ways, including being asymptomatic. As levels rise symptoms can emerge which include non-specific complaints such as headaches, abdominal pain, decreased appetite and constipation.
Lead poisoning produces a variety of complications such as “loss of cognition, shortening of attention span, alteration of behavior, dyslexia, attention deficit disorder, hypertension, renal impairment, immunotoxicity and toxicity to the reproductive organs”. (WHO, 2018) More prevalent in the U.S are the subclinical long-term effects on the central nervous system. The impairment on cognition can be evaluated by IQ tests.
The most common test used to detect and screen for lead poisoning is blood level. The current recommendation according to the American Academy of Pediatrics and Bright Futures is a risk assessment at well child visits at 6, 9, 12, 18 and 24 months and 3 to 6 years old. (Detection of Lead Poisoning, 2016) A blood sample is given if the risk assessment is positive and universal screens are not appropriate at this time.
Children with high lead tooth levels have been shown to be more inattentive, hyperactive, higher dropout rates and reading disabilities. Attention dysfunction, and disruptive social behavior such as aggression and delinquency is seen with elevated bone levels. (Lead-Exposure-in-Children, 2016)
Etiology/Prevalence/Course
Lead is a historically common element that was a widely-used for plumbing, tableware, gas, paint and many more common items. Inorganic lead is the main culprit in lead poisoning compared to its organic counterpart. The inorganic type can still be found in ceramic glazed dishes, food cans, batteries, old paint, and toys. This element can enter the body through many modes such as ingestion, inhalation and transdermal absorption. Children are most susceptible to toxicity via ingestion because of natural curiosity and normal hand to mouth activities. (Badawy, 2017)
While there have been efforts to decrease lead exposure, there are still about 4 million households that have high levels of lead that children are exposed to. In the United States there are about 500,000 children from ages 1 to 5 with blood levels about 5 mcg/dL, a level that has prolonged health consequences. (CDC, 2018)
As lead is seen in older housing, deteriorating paint and urban soil, it is no surprise that those living in lower socioeconomic areas tend to be at higher risk for greater exposure. It has been shown nationwide that minorities are greatest afflicted with African American and Mexican American children with consistently elevated rates of blood level of lead than non-Hispanic White children. (Sampson & Winter, 2016)
This racial discrepancy was most especially highlighted during the Flint, Michigan water crisis in 2014. During this time, treatment of water was insufficient and allowed lead from the pipes to seep its way into drinking water. In Flint unemployment is high and much of the people are black with 4 out of 10 families living below the poverty line. (Bellinger, 2016) During this incident it is estimated that more than 6,000 children were exposed to high levels of lead through drinking water.
As previously mentioned there are many organ systems involved and various vague symptoms due to lead poisoning. However, more serious health problems can develop, such as encephalopathy, mental retardation, growth failure, nephropathy and gastrointestinal upset.
When levels are more than 100 mcg/dL, acute encephalopathy can occur and presents with vomiting, altered mental status, seizures, ataxia or coma. (Lowry, 2017)
Another neurological issue of impairment of intelligence is seen with a lower range of 10-20 mcg/dL, it is estimated that 0.25 to 0.5 of an IQ point is lost for each 1 mcg/dL increase of blood lead levels. (WHO, 2018) Exposure is also linked to abnormal social behavior, difficultly in coordination, and decreased decision making.
Lead levels in the blood and vitamin D are inversely related, thus having a negative impact on bone and teeth development. Levels more than 40 mcg/dL are associated with an increased risk of nephropathy (WHO, 2018). Children exposed to lead are at greater risk of developing hypertension and renal failure as adults.
Gastrointestinal effects include vomiting, abdominal pain, and constipation. The reproductive system can also be effected. In men, studies suggest toxicity is associated with abnormal and decreased sperm. (CDC, 2018) During pregnancy lead exposure can cause spontaneous abortion.
Treatments/Interventions
Besides lead blood level, there are other diagnostic tests that are used in certain cases. For example, on an abdominal radiograph lead flecks in the intestinal tract indicates recent ingestion of lead containing objects. Also, a peripheral blood smear shows basophilic stippling in red blood cells.
Asymptomatic patients, should optimize nutrition including calcium, vitamin C and iron to minimize absorption rate of lead. Other management for this population include annual blood tests until 6 years old. With higher levels of 45 mcg/dL other tests are warranted such as BUN, serum creatinine, urinalysis as well as treated with chelation therapy even without symptoms.
Symptomatic lead poisoning is a medical emergency and should have many tests done such as previously stated as well as chelation therapy. Those with encephalopathy may need protection of airway by intubation however a lumbar puncture to rule out meningitis should be used in caution due to increased intracranial pressure in these children. There is a risk of seizures especially those with encephalopathy, the first line treatment are benzodiazepines and maintenance of phenobarbital.
Chelation therapy can be lifesaving in the event of lead toxicity, therefore adequate fluid administration is necessary to maintain urine output and excretion of lead. The goal is to achieve the minimum output of 300-350 ml/m2 with IV fluids containing dextrose and half normal saline.
Before treatment is needed, lead toxicity can be prevented with simple steps that can be done daily. For example, washing hands and toys, removing shoes outdoors, don’t let children play in the soil, and receive healthy nutrition. (Sampson & Winter, 2016)
There have been government public health programs and advocacy for eliminating lead levels greater than 10 mcg/dL. CDC has a Childhood Lead Poisoning Prevention Program committed to this goal as well as focusing on race and social class as a public concern. (CDC, 2018)
Other programs include environment lead remediation that can be financially reimbursed through the Health Care Finance Administration. Also, as previously mentioned children in lower socioeconomic housing often are at greater risk, and with Medicaid they cover the cost of blood lead testing.
Summary
Development is a complex process that must be carefully examined through well visits and checkups. Monitoring growth, cognition and general complaints is necessary to determine if there is a larger underlying issue that should be resolved such as lead toxicity. Blood lead levels are important to obtain when children are at high risk such as lower socioeconomic housing or stratified as appropriate candidates.
Lead has a place in history for contaminating drinking water supply, however it still is prevalent among everyday items like ceramic dishes, batteries, soil and old paint. There is no function that lead plays in the human body and it has been well established that there is no safe level in the body. Even at low levels this element can cause lasting detrimental effects on intelligence. At higher levels, it can lead to encephalopathy, seizures and death.
Chelation therapy is indicated for life saving measures and must be used appropriately without contraindications. Prevention and education are essential keys during childhood as their absorption rates are higher compared to adults. Therefore, optimizing nutrition can lower absorption rates, especially vitamin C, calcium and iron. There have already been steps to eliminating lead in paint and gasoline, yet there are still committees and programs dedicated to further eradicate exposures as lead is a major health problem in the pediatric population.