Lead exposure and poisoning prevention — formative SAQs

SAQ 1 (10 marks)

Parents of a 2-year-old live in a 1950s house. They have been sanding paint. A capillary blood lead is 8 micrograms/dL. The child is asymptomatic. [1]

1. What is the next laboratory step and why? (2) [1]
2. List five exposure sources you must cover in the history. (3) [1] [2]
3. Outline your management plan for the next month, including what you will not promise. (5) [2] [4] [6]

Model answer

Confirm with venous whole blood lead. Capillary samples can be contaminated by surface lead and should not alone drive major decisions. [1]

Sources: deteriorated paint/dust (including renovation), water plumbing, soil, take-home occupational dust, traditional cosmetics/remedies, and pica for non-food items. [1] [2]

Management: stop unsafe sanding; arrange environmental assessment/remediation pathways; educate on wet cleaning and hand washing; assess iron status and diet (iron/calcium support); developmental surveillance; public-health notification as required; retest venous BLL on schedule; test other young household members. Do not promise that any level is fully safe, and do not offer chelation as an IQ-restoring treatment — prevention and source control are the core. [2] [4] [6]

SAQ 2 (10 marks)

A 3-year-old has venous blood lead 52 micrograms/dL after paint-chip pica. The child is irritable with abdominal pain but no seizures. [1]

1. Why is this level managed differently from a BLL of 6 micrograms/dL? (2) [1]
2. What immediate environmental and clinical steps are required before or with any drug therapy? (4) [1] [2]
3. What did the TLC trial teach about succimer and cognition? (4) [6] [8]

Model answer

BLL ≥45 micrograms/dL enters the range where specialist consideration of chelation is standard in CDC-aligned guidance, and symptoms raise urgency. Lower elevations still need source control but usually not chelation. [1]

Remove the child from ongoing exposure; consider abdominal imaging for retained radiopaque material and decontamination if indicated; full clinical assessment; public-health/environmental response; iron assessment; hospital or specialist toxicology involvement for chelation decisions; never chelate while the child returns to the same uncontrolled hazard. [1] [2]

TLC randomised young children with BLL 20–44 micrograms/dL to succimer versus placebo: blood lead fell with succimer, but neuropsychological outcomes were not lastingly improved. Chelation is not a cognitive rescue; primary prevention remains essential. [6] [8]