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Lead Toxicity
Initial Check

Course: WB2832
CE Original Date: June 12, 2017
CE Renewal Date: June 12, 2019
CE Expiration Date: June 12, 2021
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This Initial Check will help you assess your current knowledge about lead toxicity. To take the Initial Check, read the case below, and then answer the questions that follow.

Case Study

A father brings his 2-year-old boy into a pediatrician's office for a routine well-child visit. The boys lives with his parents and an older sister in a rented apartment.

The pediatrician examines the boy and finds no abnormalities. The boy's growth and development indicators are within normal limits for his age.

Three years later, concerned that her child is hyperactive, the mother brings the same child, now 5 years old, to your office (his previous pediatrician recently retired).

At a parent-teacher conference last week, the kindergarten teacher said that the boy seems impulsive and has trouble concentrating. They recommended evaluation by a physician as well as by the school psychologist. The mother states that her son has always seemed restless and easily distracted, but that these first 6 months in kindergarten have been especially difficult.

He has also complained recently of frequent intermittent abdominal pains and constipation. The mother gave him acetaminophen for stomach pains with little change. She has also been giving him a fiber laxative, which has reduced the frequency and severity of constipation. She wonders if the change to attending kindergarten has played a role in his increased complaints.

Family history reveals that the boy's parents are divorced. He lives with his older sister, mother, and maternal grandparents in an older suburb of your community. The parents divorced when the boy was three years old. The father works in retail at a local shopping center. The child visits with his father one weekend a month, which is working out fine. However, he seems to be fighting more with his sister, who has been diagnosed with attention deficit hyperactivity disorder (ADHD) and is repeating first grade. Since the mother moved in with her parents after her divorce 2 years ago, she has worked with the grandfather in an automobile radiator repair shop, where her children often come to play after school. She has recently been laid off and has expressed worry about increasing financial dependence on her parents as the children grow older. She also worries that the grandfather, who has gout and complains increasingly of abdominal pain, may become even more irritable when he learns that she is pregnant from the father of her son. Her third child is due in 61/2 months. The father has no lead exposure risk factors.

When you inquire about the home, she explains that it was built in the 1960s. Her father bought it 30 years ago at a good price, as it is on a busy street close to the center of town. She has no idea of the type of pipes they have or the source of drinking water. They don't use any kind of water filtration system. The yard is bare. She doesn't see her father doing any improvements to the house due to his economic situation.

You ask about smoking habits and learn that the mother smokes up to a pack of cigarettes a day, sometimes in front of the children at home. The grandfather also smokes, but seldom in front of the children.

On chart review, you see that the previous pediatrician examined the boy for his preschool physical 1 year ago. A note describes a very active 4 year old who could dress himself without help but could not correctly name the primary colors. His vision was normal, but hearing acuity was below normal according to a hearing test administered for his preschool physical. The previous doctor noted that the boy's speech and language abilities were slightly delayed. Immunizations are up to date.

Further history on last year's visit indicated adequate diet, with no pica behavior. Hemoglobin 10 g/dL and low ferritin. Hematocrit was diminished at 30%. Peripheral blood smear showed hypochromia and microcytosis. There was no evidence of blood loss, and stool examination was negative for occult blood. The diagnosis was "mild iron deficiency anemia," and elemental iron 5 milligrams/kilograms (mg/kg) per 24 hours (divided 3 times daily without food) was prescribed. The family failed to keep several follow-up appointments, but the child did apparently complete the prescribed 3-month course of iron supplements. He received no medications and had no known allergies. No psychological studies, learning, speech or behavioral evaluations were performed.

On physical examination today, you note that the boy is in the bottom 10th percentile for height and weight. The previous year he was plotted at the 20th percentile. His attention span is very short, making him appear restless. He has difficulty following simple instructions. Except for hearing acuity below normal, slightly delayed language, and social skills, the boy has reached most important developmental milestones.

Initial Check Questions

  1. What information (if taken at his age 2 well child visit) would have assisted with prevention and early identification of lead exposure risks?
    1. Smoking status of parents.
    2. Age and condition of boy's primary residence.
    3. Occupations of family members.
    4. Drinking water source and delivery system.
    5. B and D.
    6. All of the above.
  2. What should be included in this boy's problem list?
    1. Delayed language ability, slightly impaired hearing.
    2. Short stature, history of hypochromic, microcytic anemia (treated with iron supplementation), abdominal pain, constipation.
    3. Possible attention deficit hyperactivity disorder, school and family stressors, lead exposure risk.
    4. A and C.
    5. All of the above.
  3. What test would you order to confirm or rule out your diagnosis?
    1. Capillary blood lead level (finger stick).
    2. Abdominal radiograph.
    3. Venous blood lead level (BLL).
    4. Erythrocyte protoporphyrin (EP)/zinc protoporphyrin (ZPP) level.
  4. Which other family member is most vulnerable for effects of lead exposure at this time?
    1. The mother.
    2. The older sister.
    3. The unborn baby.
    4. The grandfather.

Initial Check Answers

  1. What information (if taken at his age 2 well child visit) would have assisted with prevention and early identification of exposure risks?

    The best choice is Answer F. All of the above.

    Two of the obvious sources of lead suggested in the case study are leaded paint at home (paint flakes, household dust, and soil) and fumes and dust from solder at the radiator repair shop. However, smoke from cigarettes is also a source of lead that can be an important exposure (first, second or third-hand) to children. He or she could have explained the need to quit smoking not only in front of the children, but in the home, as tobacco and its toxins adhere to the furniture, clothing and walls (third hand smoking). Other information that would have assisted with prevention and early identification of lead exposure risks is the drinking water source and delivery system, as well as the occupations of the mother and father.

    You can ask questions about the age of the family's house, when it was most recently painted, and the condition of the paint to get a preliminary sense of the potential extent of this exposure pathway. If the house was built before 1978, the child may be exposed to higher lead content paint chips, lead-contaminated soil, or lead in dust in the home.

    Additionally, you should determine if the boy ever had pica (a compulsive eating of non-food items, to be distinguished from normal hand-to-mouth behavior of children). Pica is more common in children ages 2 to 5, so it is likely that this is a present behavior. You can also ask about the length, type, and precise location of the boy's play at the radiator shop.

    More information for this answer can be found in the "Clinical Assessment - Diagnostic Tests and Imaging" section.

  2. What should be included in this boy's problem list?

    The best choice is Answer E: All of the above.

    History suggests

    • Delayed language ability,
    • Slightly impaired hearing,
    • Short stature,
    • Possible attention deficit disorder,
    • Anemia, and
    • Abdominal pain.

    The child is also experiencing passive exposure to his mother's cigarette smoke and family disruption and possible stress related to his parents' divorce, or possibly to attending kindergarten.

    More information for this answer can be found in the "Clinical Assessment - Signs and Symptoms" section.

  3. What test would you order to confirm or rule out your diagnosis?

    The best choice is Answer B. Venous blood lead level (BLL).

    To confirm lead poisoning, the best test is a venous BLL. Capillary blood draws (finger-sticks) are not considered reliable for diagnosis purposes. A venous or a screening capillary BLL is usually the first test drawn, instead of the EP/ZPP. Erythrocyte protoporphyrin (EP), commonly assayed as zinc protoporphyrin (ZPP), is not sufficiently sensitive at lower BLLs and therefore is not as useful a screening test for lead exposure in children.

    If the BLL is below 25 µg/dL, then a serum ferritin level and other iron studies can be used to determine if iron deficiency anemia exists.

    More information for this answer can be found in the "Clinical Assessment - Diagnostic Tests and Imaging" section.

  4. Which other family member is most vulnerable for effects of lead exposure at this time?

    The best choice is Answer C. The unborn baby.

    While the mother may be at risk, the unborn baby has the highest risk of neurodevelopmental problems. The mother has recently been laid off, ending the ongoing occupational exposure for her and her unborn child. However, her lead body burden can continue to expose the unborn child because the bone lead from all sources is mobilized during pregnancy and passed to the fetus through the mother's blood. The unborn baby is also at risk if the mother currently smokes or has smoked in the past. In addition, the baby will be at risk to potential home-based sources when he or she begins to move around and mouth objects. Prenatal exposure and exposure at a very young age to lead can damage development of the brain.

    Additional sources of exposure for the children include possibly playing at the radiator repair shop after school, and, since the grandfather still works there, take-home exposure if he brings contaminated clothes or shoes into the house. This is especially important for the pregnant mother, whose occupational exposure has ended but who may still be exposed by the take-home exposure from her father's clothes/shoes. The person handling these clothes and doing the laundry may also be exposed.

    The grandfather may be exposed, as he shows irritability and abdominal pain. If this source is removed (using "lead safe" practices or switching jobs) he should recover. You should, however, suggest that he should be tested and talk to his physician about it. The older sister might be at risk from exposure in the home or radiator repair shop, although because she is older she will probably ingest less lead through hand-to-mouth behavior at this time. However, her history also suggests she may have been exposed as a younger child as well.

    More information for this answer can be found in the "Who Is at Risk of Lead Exposure?","What Are U.S. Standards for Lead Levels?" and "What Are Possible Health Effects from Lead Exposure?" sections.

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