Physician's Handbook on Childhood Lead Poisoning Prevention
Chapter Five
Medical Management of Children with Elevated Blood Lead Levels
Medical Management of Children with Elevated Blood Lead Levels
Case Management of Children Based on Identified Lead levels
Summary
- Confirm an elevated capillary blood lead level of equal to or greater than 15 μg/dL with a venous blood lead test.
- Erythrocyte protoporphyrin (EP) testing may help to determine if the elevated lead level is related to an acute or chronic exposure. An EP level will be elevated with chronic exposure especially when the blood lead level is over 35 μg/dL.
- Children with elevated blood lead levels should be tested for iron depletion or deficiency, as more lead is absorbed when iron stores are depleted. Serum ferritin is the best measure of iron status in children.
- Children with venous blood lead levels equal to or greater than 20 μg/dL should have a complete neurological and medical evaluation, including a developmental screening, nutritional assessment and detailed lead exposure history.
- For children with venous blood lead levels equal to or greater than 20 μg/dL, an environmental assessment should be performed. Notify the local health department of the child's blood lead level so that an environmental assessment can be performed and a public health nurse home visit can be made.
- Children with venous blood lead levels equal to or greater than 45 μg/dL should be chelated. If a child's blood lead level is equal to or greater than 45 μg/dL, notify the local health department within 24 hours of receipt of the blood lead level results so that public health follow-up activities can be initiated immediately.
- Children with venous blood lead levels equal to or greater than 70 μg/dL require emergency hospitalization and chelation. Admission to, or consultation with, a Regional Lead Poisoning Prevention Resource Center or other experienced facility is advised.
Medical Management of Children with Elevated Blood Lead Levels
This section of the manual will provide a discussion of the basic principles of management of children with elevated blood lead levels. The 1991 CDC Statement contains a great deal of information about chelating agents and how to use them.
Before embarking on an aggressive course of chelation, always repeat the blood lead level with a venous specimen. This is very important, especially with elevated capillary blood lead levels, as falsely high levels can occur due to contamination of a capillary specimen with lead dust from the skin. Specimens can be run on a STAT basis with less than a 24-hour turnaround by some laboratories when the result is urgently needed.
There are many things families can do to reduce ingestion, inhalation and absorption of environmental lead. Parents need to know the potential sources of lead in the home environment in order to identify sources in their home. They should understand the methods for controlling house dust which may be contaminated with lead. They should be advised of the need for frequent hand washing to reduce exposure to dust on fingers and close supervision to reduce mouthing behavior by the child. These behaviors will reduce ingestion and inhalation of lead. They should be advised of the benefits of appropriate calcium and iron nutrition to reduce absorption of ingested lead. Parent education can be reinforced at a public health nurse home visit by the local health department (see order form for parent information materials).
The clinical evaluation of children with elevated blood lead levels varies with the level found. Testing can be performed to differentiate between acute and chronic exposures. This information may be beneficial in determining if treatment for an acute exposure is indicated. A number of tests may be used to determine if lead exposure is acute or chronic. The erythrocyte protoporphyrin (EP) will be elevated with chronic exposure, especially when the blood lead level is over 35 μg/dL. EP over 150 μg/dL is almost always due to lead. EP 35-150 μg/dL may be due to elevated lead levels or iron deficiency. With chronic exposure, X-ray films will show areas of increased density at the metaphyseal plates of the distal femur, proximal tibia and fibula. Although they are called "lead lines," these areas of density are not the result of lead itself, but rather arise due to disruption of normal bone metabolism by lead. With acute ingestion of paint chips or other objects containing lead, abdominal X-ray films may show dense objects in the small intestine or colon.
Children should be assessed for iron depletion or deficiency, as lead is more readily absorbed when iron stores are depleted. Serum ferritin is the best measure of iron status in children. It will show iron depletion well before the serum iron, iron binding capacity and tests for anemia become abnormal. Children with iron depletion should be treated with supplemental iron.
Children with blood lead levels of > 20 μg/dL should have neurological and medical evaluations including developmental screening tests to identify possible developmental delay. Use of a screening test specifically designed to assess speech and language has been recommended as being a sensitive indicator in the toddler age and because lead has been shown to affect hearing. Children with abnormal screening tests for development or speech and language function should be referred to the local Early Intervention Program for a formal developmental assessment.
For children with blood lead levels of > 20 μg/dL, an environmental assessment should be performed in order to identify the source of lead exposure, along with a public health nurse home visit to provide risk reduction counseling. The local health department's Childhood Lead Poisoning Prevention Program can advise pediatric care providers and families about how to obtain an environmental assessment. In most counties, the investigation will be done by local health department staff. In some smaller counties without full service health departments. The assessment will be done by staff at the State Department of Health's district offices. Local public health nurses may identify obvious lead hazards when they make a home visit to provide risk reduction education to the family.
The environmental staff of local health units are responsible for identifying lead hazards and making recommendations to the property owner regarding abatement of the hazard. Parents and primary care providers should also be informed of findings and follow-up visits to assure that timely abatement of hazards has occurred.
Once a child with elevated lead levels has been identified, exposure to lead must be avoided. When levels are > 20 μg/dL, it may be necessary to advise the family to move the child to another location which is free of lead while the home is inspected for lead and lead hazards are remediated. Some localities have developed "lead safe" housing resources for temporary placement of families who have children with lead poisoning. The local Childhood Lead Poisoning Prevention Program will know if such resources are available in the county. Assistance from county social services departments may be needed to obtain alternative housing for some patients with limited resources.
Some experts may use a lead mobilization test to determine which children with lead levels in the 20-44 μg/dL range will benefit from chelation. The lead mobilization test involves a single dose of a chelating agent and complete urine collection over the following eight hours. This will determine how much lead is excreted in response to the chelating agent.
It should be noted that during a lead mobilization test, iron deficiency can inhibit the amount of lead diuresed after a dose of the chelation agent EDTA. However, iron deficiency only leads to false lead mobilization tests around 35 mcg/dL. Reliable lead mobilization test results will be obtained at higher and lower blood lead levels even in the presence of iron deficiency. Since iron status may affect the outcome of the test, it should not be performed until the child is iron replete. Therefore, treatment in iron deficiency may result in unnecessary delay of treatment for lead poisoning.
It is strongly recommended that all children with lead levels 45 μg/dL or higher have chelation treatment. Pharmacology and clinical aspects of chelation are discussed in detail in the 1991 CDC statement and in review articles in the medical literature. Primary pediatric care providers caring for children in need of chelation should consult with experts in the field. Pediatric care providers may want to refer children to a facility with extensive experience in chelation. Regional Lead Resource centers have been established at eight teaching hospitals across the state to accept these referrals (see Appendix D).
Periodic follow-up of children with elevated blood lead levels is essential. At follow-up, pediatric care providers can assess nutrition, growth, development, compliance with recommended risk reduction practices, abatement or reduction of lead hazards in the home environment and providers can obtain repeat blood lead tests to determine if the lead level is rising or falling.
Case Management of Children Based on Identified Lead Levels
Classification of The Child With Confirmed Venous Lead Poisoning and Recommended Action
Class I: Blood lead level 9 μg/dL or below
No recommended action. Conduct follow-up with screening as indicated by age, history and risk assessment tool.
Class IIA: Venous Blood lead level 10-14 μg/dL
The recommended threshold of concern is a blood lead level of 10 μg/dL or greater in children. The range of error in blood lead testing is 2-4 μg/dL.
An environmental history is advisable. Provide family with risk reduction and nutrition education. Local health units will work with health care providers in these efforts. Follow-up blood lead tests are recommended every three to four months. If two consecutive lead tests are <10 μg/dL, retest in a year. No special medical evaluation or developmental assessment is necessary.
If large numbers of patients are found in this category, communitywide education, nutritional counseling and environmental intervention campaigns are prudent. Early detection and control can minimize intellectual deficits and behavioral disturbances (see order form for further information that can be provided to parents about risk reduction and nutrition).
Class IIB: Venous blood lead level 15-19 μg/dL
Take a careful environmental history about possible sources of lead exposure. Provide risk reduction and nutrition education, i.e., control of lead hazards in paint, dust, water and soil; avoidance of lead contamination in home renovations, occupations and hobbies; and the importance of proper nutrition.
Follow-up venous blood lead every three to four months. If the blood lead level remains 15-19 μg/dL on two consecutive tests, environmental investigation and intervention conducted by the local health unit should be considered. If three consecutive blood lead levels are <15 μg/dL, retest annually.
Ferritin should be obtained to assess for iron deficiency. No other special medical evaluation or developmental assessment is recommended. These lead levels are generally asymptomatic, however, make sure other children under the age of six years in the dwelling have been tested for lead.
Class III: Venous blood lead level 20-44 μg/dL
A confirmatory venous blood lead level must be done within one week. With a confirmed blood lead level in this range, the patient needs a full medical evaluation including a detailed environmental and behavioral history. Physical examination should include a neurological examination, evaluation of language development and a formal developmental screening test. A serum ferritin level should be obtained to assess for iron deficiency.
If the primary care physician has limited experience with lead poisoning, he/she may wish to refer to the Regional Lead Poisoning Prevention Resource Centers (see appendix D) for evaluation to determine if lead mobilization test (LMT) or chelation therapy is needed. Some authorities recommend conducting a lead mobilization test (LMT) for children with lead levels between 25-44 μg/dL to determine the need for chelation therapy.
For children with a blood lead level equal to or greater than 20 ug/dL, further medical evaluation and environmental investigations to identify the source of lead are required. Environmental investigators are provided or arranged by the local health unit. Free telephone consultation for treatment and patient management issues is provided by Regional Lead Resource Centers. (See appendix D) Remediation of environmental hazards is managed by the local health unit. Children with venous blood lead levels of 20 ug/dL or greater must receive a developmental assessment since children with elevated blood lead levels are at risk of developmental delay. Children under three years of age should be referred to the local Early Intervention Program. Children over three years of age should be provided with a developmental assessment. The results of the assessment should be provided to the local health unit's Childhood Lead Poisoning Prevention Program. If the provider is unable to administer a developmental assessment, a request for assistance should be made to the local lead program. A list of local Childhood Lead Poisoning Prevention Programs is available. (See appendix G).
The patient and family need risk reduction education, nutritional counseling and an environmental investigation. Refer to local health unit for an environmental investigation and collaborate with the local health unit on appropriate follow-up activities (see appendix G for local lead programs). Obtain follow-up venous blood level within three to four months or more often as indicated. Make sure other children under the age of six years in dwelling have been tested for lead.
Class IV: Venous blood lead level 45-69 μg/dL
Do a confirmatory venous blood lead and begin medical treatment within 48 hours. If the confirmed blood lead level is in this range, the patient needs urgent medical care, including a medical evaluation with detailed history, physical examination and tests for iron deficiency.
These patients will need pharmacologic therapy; Succimer (DSMA) may be used for oral chelation therapy provided the child resides in a lead safe environment. Dimercaprol and calcium disodium thylenediamine tetra acetate (BAL & EDTA) parenterally are used for children with symptomatic lead poisoning. When a child is hospitalized, the child must not be discharged to a lead environment. Refer to a Regional Lead Resource Center with staff experienced in dealing with lead toxicity. (See appendix D.) Refer child to the local health unit's Program whenever the child is below 36 months of age. For referral to the Early Intervention Program, see appendix H for a list of the local early intervention officials. If the child is three to five years of age and the developmental screening test suggests developmental problems, the child should be referred to the local school district's committee for preschool special education.
.Class V: Venous Blood Lead Level 70 μg/dL and above
Do a confirmatory venous blood lead level immediately. If the blood lead level is > 70 μg/dL, the patient requires emergency hospitalization and chelation. Admission to or consultation at a Regional Lead Poisoning Prevention Center (see appendix E) or other experienced facility is advised. When a child is hospitalized, the child must not be discharged into a lead environment. Alternative housing should be provided.
Prior to discharge, these patients need a full medical evaluation, detailed history and thorough physical examination (including neurological examination and complete developmental assessment) and testing for iron deficiency. Refer the child to the Infant Child Health Assessment Program. A child suspected of having a developmental delay or disability should be referred to the Early Intervention Program. If the developmental assessment determines that the infant or toddler has special needs, then the Early Intervention Program (see appendix I) will develop a plan with the family to provide needed services.
Collaborate with local health units on appropriate follow-up activities and referrals, see appendix H for local lead programs. Refer to local health department for an immediate environmental investigation. Patient and family need risk reduction education and nutritional counseling.
Lead encephalopathy is almost always associated with blood lead concentrations >100 μg/dL, although it has been reported at levels as low as 70 μg/dL.
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