Lead toxicity w/new focus: Addressing low-level lead in Can children

Question 1

Symptoms of acute or subacute lead toxicity?

Answer 1

-Headache, abdominal pain, anemia, constipation, vomiting, clumsiness, somnolence, stupor, renal failure, seizures, possible death

Question 2

In 2003 the WHO estimated that ___% of mild intellectual disability worldwide is caused by lead exposure.

Answer 2

3.5%

Question 3

What is the current pediatric “level of concern” for BLL in Canada and USA?

Answer 3

5mcg/dL

Question 4

Most vulnerable population for lead exposure?

Answer 4

Children <3 years of age

Question 5

What are potential environmental sources of lead exposure in Canadian children - prenatally, and in infancy and childhood?

Answer 5

• Prenatally: exogenous lead exposures during pregnancy, as well as from maternal endogenous stores
• Infancy and childhood: ingestion, inhalation, and/or dermal absorption

Question 6

Preschool children can absorb approximately ___% of the lead they ingest, adults absorb about __%.

Answer 6

40, 10

Question 7

Where is approximately 70% of the body’s stored lead? When can it be re-released into the bloodstream?

Answer 7

Bones - can be re-released into the bloodstream during remodelling of bones during childhood, adolescence or old age, or in response to stress, pregnancy or malnutritioni

Question 8

Most common sources of lead exposure in young children?

Answer 8

• Food and water
• Household dust and soil
• Mouthing products that contain lead

Question 9

How does lead get into food?

Answer 9

• May accumulate in food grown in soil on previous industrial sites or next to old buildings or busy roads
• Can also be present in water or air, or introduced in other ways during growth, transportation, preparation and storage

Question 10

What has greatly reduced lead exposure through food in most countries, including Canada?

Answer 10

Banning the use of lead solder in food cans

Question 11

Why might Indigenous peoples be at risk?

Answer 11

If they hunt and eat a traditional diet, including meat from animals shot with lead bullets

Question 12

In older homes and neighbourhoods, tap water may be contaminated by lead pipes installed before ____ or repaired with lead solder used until the ____s.

Answer 12

1960, 1980s

Question 13

Consider blood lead testing for children who have:

Answer 13

• Lived in a house or apartment built before 1960 within the past 6 months, especially when water is supplied by lead piping or original paint is present, peeling or chipped, or the dwelling is under renovation
• A sibling, housemate, or playmate with a history of lead poisoning
• PICA or have eaten pain chips, or tend to mouth painted surfaces
• Emigrated or been internationally adopted from a country where population lead levels are higher than in Canada
• Any one of the above RFs, combined with a known or suspected neurodevelopmental disorder

Question 14

Most vulnerable subpopulations?

Answer 14

• Children who already carry a higher burden of lead in their bodies (e.g. infants born to mothers who have experienced exposures themselves or lacked divalent minerals (e.g. calcium, magnesium, iron, zinc) during pregnancy)
• Children exhibiting PICA or with a neurodevelpmental deficit such as ASD, especially if they tend to mouth objects
• In the US, African-American or other children living in poverty, because lead exposures from older or deteriorated housing may be combined with having poor nutrition
• Children with a mineral deficiency (e.g. calcium, iron, zinc) due to shared absorptive pathways

Question 15

Symptoms of low-level lead exposure?

Answer 15

• Often asymptomatic
• When symptoms present, usually subtle
• May include:
• cognitive delay or other neurodevelopmental signs e.g. inattention, hyperactivity, hearing impairment, poor balance, speech delay

Question 16

What investigations to consider in cases of suspected lead exposure? What else to do?

Answer 16

• Blood lead (venous sample)
• CBC
• Ferritin
• Calcium, protein, albumin

-Focused nutritional history and neurodevelopmental assessment with ongoing follow-up also recommended

Question 17

When an index case of lead exposure has been identified, consider activating a _____ for other household members or close contacts.

Answer 17

Pediatric Environmental Health History (PEHH)

Question 18

Gold standard to confirm recent lead exposure?

Answer 18

Elevated venous blood lead level

Question 19

Half life of lead in RBCs?

Answer 19

Approximately 45 days

Question 20

At what age to children’s BLLs typically peak?

Answer 20

2-3 years

Question 21

What can happen when exposure ceases?

Answer 21

BLLs can decline, but lead can move into other parts of the body, especially bone, rather than being excreted

Question 22

Can a current low BLL satisfactorily rule out lead as a contributing factor to symptoms?

Answer 22

No.

Question 23

Children with BLL higher than ____mcg/dL (___mcmol/L) should be investigated thoroughly, and any identified exposure sources should be mitigated as soon as possible.

Answer 23

5, 0.24

Question 24

To convert mcmol/L to mcg/dL?

Answer 24

Multiply by 20.72

Question 25

What is the safe threshold for lead?

Answer 25

There isn’t one.

Question 26

PEHH criteria for Home/Child care/school?

Answer 26

• Neighbourhood established in the 1960s or before, especially if supplied by lead water pipes or if lead solder was used for piping or plumbing fixtures
• Buildings constructed in the 1980s or earlier, if lead paints are present and especially if exposed areas were painted before 1960
• Building where child spends times is in a poor state of repair
• Proximity to current or past industrial or waste site
• Proximity to a busy roadway (<30 yards distant) or an airfield, where small-engine planes approach or take off

Question 27

PEHH criteria for consumer products?

Answer 27

• Costume jewelry
• Candles (e.g., lead in wicks)
• Imported painted toys, wax crayons, mini-blinds, vinyl items (e.g., toys, containers, lunch boxes), painted reusable bags
• Cosmetics (e.g., kohl)

Question 28

PEHH criteria for food?

Answer 28

• Imported sugar, candy and baking supplies
• Food prepared with, served or stored in containers made of pewter or ceramic (especially with a leaded glaze), or leaded crystal
• Foods, particularly vegetables in the Brassica family, grains and other foods that may accumulate lead (e.g., dandelion greens growing along busy roadways, or cabbages or kale grown by the foundation of an old home or in untested inner-city soil)
• Wild game shot with lead bullets

Question 29

PEHH criteria for occupation and hobby-related?

Answer 29

• Battery manufacturing and recycling
• Radiator repair, welding
• Lead mining and smelting
• Brass and bronze foundry work
• Demolition and renovations
• Hunting, marksmanship, military (e.g., a firing range)
• Pottery glazing
• Leaded glass

Question 30

PEHH criteria for family factrs?

Answer 30

• Mother may have been exposed to lead before or during pregnancy
• Previously lived in a country or region with higher population lead levels
• Sibling or other close contact with lead exposure

Question 31

When is chelation therapy indicated?

Answer 31

High BLLs, and must be conducted by a physician expert in this area

Question 32

Potential long-term consequences of both acuute and low-dose chronic lead exosures?

Answer 32

• Hypertension
• Vascular disease
• Renal impairment
• Aberrant behaviour

Question 33

Management of lead toxicity if BLL 5-14mcg/dL?

Answer 33

1. Review lab results with the child’s family.
2. Perform routine health maintenance, including neurodevelopmental screening, and assess nutrition.
3. Take a careful PEHH to identify potential sources of exposure. Provide preliminary advice about reducing or eliminating exposure source(s).
4. Contact local public health authority for guidance.
5. Re-test venous BLL at 1 to 3 months to ensure the child’s lead level is not rising. If it is stable or decreasing, retest in 3 months.
6. Provide nutritional counselling related to calcium and iron. Recommend having a fresh fruit with every meal because iron absorption quadruples when taken with vitamin C-containing foods. Encourage the consumption of iron-enriched foods (e.g., cereals, meats). Ensure iron sufficiency with adequate laboratory testing (CBC, ferritin, CRP) and treatment. Consider starting a multivitamin with iron.
7. Complete a full neurodevelopmental assessment and follow-up. Lead’s effects on development may manifest over years.

Question 34

Management of lead toxicity if BLL 15-44mcg/dL?

Answer 34

1. Perform steps as for BLLs 5 to 14 mcg/dL.
2. Confirm the BLL with repeat venous sample at 1 to 4 weeks.
3. Additional, specific evaluation of the child, such as abdominal x-ray should be considered based on the PEHH. Gut decontamination may be considered if ingested foreign objects are visualized on x-ray.
4. Contact your local Poison Centre for assistance.
5. Chelation is not typically recommended for asymptomatic patients.

Question 35

Management of lead toxicity iif BLL >44mcg/dL?

Answer 35

1. Follow guidance for BLLs 15 to 44 mcg/dL.
2. Confirm the BLL with repeat venous testing at 48 hours.
3. Consider hospitalization and/or chelation therapy in consultation with your local Poison Control Centre. Mitigating lead exposures at home, identifying other possible sources, assessing the family’s social situation, and chronicity of the exposure will influence management.