Lead Poisoning ✅

Question 1

How can childhood exposure to lead occur in developed countries?

Answer 1

• Environmental sources in the home, e.g. leaded paint
• Lead contaminated dust and soil
• Water contaminated by lead pipes

Question 2

Is significant toxicity from lead common in developed countries?

Answer 2

No, it’s rare

Question 3

Where is lead a much more significant problem?

Answer 3

In the developing world

Question 4

What is the most common source of lead poisoning in the developing world?

Answer 4

Lead-glazed ceramics

Question 5

Why is lead glazed ceramics a leading cause of lead poisoning in the developing world?

Answer 5

Their production is often a home-based industry in which children are actively employed

Question 6

What are the other sources of lead in developing countries?

Answer 6

• Leaded petrol
• Groundwater contamination from mining, smelting, and battery factories
• Exposure to other occupational sources through parents

Question 7

What are the toxic effects of lead related to?

Answer 7

Dose

Question 8

What is a normal concentration of lead in the blood?

Answer 8

<0.5

Question 9

What is the effect of blood lead concentrations of 0.5-1?

Answer 9

Developmental and growth delay

Question 10

What is the effect of blood lead concentrations of 1-2?

Answer 10

Haemoglobin begins to fall

Question 11

What is the effect of blood lead concentrations of 2-3?

Answer 11

Nerve conduction velocity impeded

Question 12

What is the effect of blood lead concentrations of 3-4?

Answer 12

Overt anaemia

Question 13

What is the effect of blood lead concentrations of 4-5?

Answer 13

Severe CNS toxicity

Question 14

What is the effect of blood lead concentrations of 5-6?

Answer 14

Increasing risk of death

Question 15

Why is the potential for adverse effects of environmental lead in children higher than in adults?

Answer 15

• Smaller body size leads to greater per unit body weight exposure
• Young children are orally exploratory, making them more likely to ingest lead-containing dust and soil
• Physiological update rates of lead are higher in children than adults
• Potential for adverse developmental effects

Question 16

What are the pools of lead distribution in the body?

Answer 16

• Blood
• Skin and muscle
• Bone and dentine

Question 17

What % of lead distributes into the blood?

Answer 17

2%

Question 18

Where is lead mostly found within the blood?

Answer 18

Bound to the erythrocyte membrane

Question 19

What % of lead distributes to the skin and muscles?

Answer 19

2-3%

Question 20

What % of lead distributes to bone and dentine?

Answer 20

95%

Question 21

What is the biological half life of lead distributed to bone and dentine?

Answer 21

20-30 years

Question 22

What systems are affected by the toxic effects of lead?

Answer 22

• Haematological
• Neurological
• Renal

Question 23

How does lead affect the haematological system?

Answer 23

By affecting enzymes essential for the production of haem

Question 24

What enzymes essential for the production of haem are affected by lead?

Answer 24

• 5-aminolaevulinic acid dehydratase (ALAD)

- Ferrochelatase

Question 25

What is the result of leads effect on enzymes essential for the production of haem?

Answer 25

- Anaemia | - Elevated plasma concentrations of 5-aminolaevulinic acid (ALA) and zinc protoporphyrin (ZPP)

Question 26

What are the features of the anaemia caused by lead poisoning?

Answer 26

- Microcytic | - Hypochromic

Question 27

How might lead poisoning manifest neurologically?

Answer 27

Cognitive impairment

Question 28

When might lead poisoning manifest with cognitive impairment?

Answer 28

- As a result of chronic low-level lead exposure | - Acute encephalopathy

Question 29

What is the mechanism of neurotoxicity in lead poisoning?

Answer 29

Unknown

Question 30

How might lead poisoning affect the kidneys?

Answer 30

Acute severe lead exposure may give rise to proximal tubular dysfunction resulting in glycosuria and aminoaciduria

Question 31

What kidney pathology might result from chronic lead exposure?

Answer 31

Interstitial nephritis

Question 32

What is the most important initial aspect of the management of lead poisoning?

Answer 32

Removal of the child from the source of exposure

Question 33

What is required in order to remove the child from the source of lead exposure?

Answer 33

A comprehensive environmental assessment

Question 34

What is used in the treatment of lead poisoning?

Answer 34

Chelating agents

Question 35

What is the purpose of chelating agents in lead poisoning?

Answer 35

To enhance the elimination of lead

Question 36

How do chelating agents enhance the elimination of lead?

Answer 36

They form water-soluble complexes with lead, preventing its binding to cell components

Question 37

What happens to complexes produced with lead by chelating agents?

Answer 37

They are excreted in the urine

Question 38

What are the most widely used chelating agents in lead poisoning?

Answer 38

- IV sodium calcium edetate (EDTA) | - Oral succimer (2,3-dimercaptosuccinic acid, DMSA)