2. • Introduction to lead
• What is lead poisoning
• Sources of exposure
• Classification of lead poisoning
• Who is at risk
• Pathophysiology
• Harmful effect of lead
• Signs and symptoms
• Diagnosis and Treatment
• Prevention conclusion Contents
3. • More industrial workers are exposed to lead than to any other toxic metal.
• Lead is widely used in a variety of industries because of its properties:
• Low boiling point
• Mixes with other metals easily to form alloys
• Easily oxidised
• anticorrosive
4. • All lead compounds are toxic:
• Lead arsenate
• Lead oxide
• Lead carbonate
• Lead sulphide is the least toxic.
Most dangerous
5. • Lead poisoning is a medical condition caused by increased levels of the heavy
metal lead in the body, and this can interfere with a variety of body processes and
causes toxicity to many organs and tissues.
• It’s also called plumbism, colica Pictonum or saturnism.
7. • Industrial Uses: Over 200 industries are counted where lead is used. Manufacture
of batteries, glass , ship building, printing, potteries rubber industry and several
others.
8. • Occupational exposure: is the main cause of lead poisoning in adults, as
in lead miners and smelters, plumbers glass manufacturers, construction
workers …etc.
• Paints: is the main cause of lead Poisoning in children. Many of the
children display pica, so even a small amount of a lead-containing product
can contain hundreds of milligrams of lead.
9. • Soil: is the main cause of lead poisoning in the agricultural areas. By eating
food grown in contaminated soil.
• Water: Lead from the soil or atmosphere can end up in surface water and
groundwater. It is also potentially dangerous to be present in drinking water.
11. • Hunting: Animals which are hunted are at high risk of exposure because of
the bullets which may contain lead.
• Breast feeding is also considered as an important route of lead exposure
because of the presence of the lead in the affected female milk.
12. Non- Occupational Sources:
• Greatest source – Gasoline.
• Thousands of tons of lead every year is exhausted from automobiles.
13. Depends on:-
• 1- The amount of lead in the blood and tissues.
• 2- The time of exposure. Lead poisoning may be acute (from intense
exposure of short duration) or chronic (from repeat low-level exposure over
a prolonged period).
14. Classification
• Acute poisoning:- In acute poisoning, typical neurological signs are pain,
muscle weakness.
• Gastrointestinal problems, such as diarrhoea, poor appetite, or weight loss.
Absorption of large amounts of lead over a short time can cause shock,
Hemolysis. Damage to kidneys can cause changes in urination such as
decreased urine output.
15. Classification
• Chronic poisoning :- usually presents with symptoms affecting multiple
systems, but is associated with three main types of symptoms:
• gastrointestinal, neuromuscular, and neurological. Signs of chronic exposure
include loss of short-term memory, depression, nausea, abdominal pain, loss
of coordination, and numbness and tingling in the extremities.
16. Who is at risk
• All children under the age of 6 years old.
• People living in old houses are at great risk.
• People working in industries.
• Pregnant woman & developing baby.
17. Normal levels of lead??
• Body stores avg in Adults: 150 to 400mg
• Blood: avg. 25 mcg/100ml
• Increase to 70mcg/100ml – clinical symptoms.
• Normally, 0.2 – 0.3 mg largerly from food and beverages.
• Children: Less than 10 micrograms/dL of lead in the blood
18. Mode of Absorption
INHALATIONAL:
• Most cases of industrial lead poisoning is due to inhalstional of fumes and
dust of lead or its compounds.
19. Mode of Absorption
INGESTION:
• Is of less common occurrence
• Small quantities of lead trapped in the Upper respiratory tract may be
ingested.
• Lead may also be ingested in food or drink through contaminated hands.
20. Mode of Absorption
SKIN
• Absorption through skin occurs only in respect of the organic compounds
of lead.
• Tetraethyl lead.
• Inorganic compounds are not absorbed through skin.
21. Mode of Absorption
• The main body compartments that store lead are the blood, soft tissues, and
bone; the half-life of lead in these tissues is measured in weeks for blood,
months for soft tissues, and years for bone.
• Lead in the bones, teeth, hair and nails is bound tightly and not available to
other tissues, and is generally thought not to be harmful.
22. • In adults, 94% of absorbed lead is deposited in the bones and teeth.
• In children only store 70% in this manner, a fact which may partially account
for the more serious health effects on children.. Many other tissues store lead
are the brain, spleen, kidneys, liver, and lungs. It is removed from the body
very slowly, mainly through urine. Smaller amounts of lead are also
eliminated through the feces, hair, nails, and sweat.
23. • Distribution of lead:-
• 95% of ingested lead is excreted in faeces.
• Lead absorbed from gut enters the circulation 95% enters erythrocytes.
• Transported to liver and kidneys finally to bones
• Released during osteolysis ( during bone resorption ) to soft tissues.
• 4% brain, liver, kidneys.
• 1% blood.
• Crosses placenta, foetal BBB is open
24. • It probably exerts its toxic action – by combining wit SH groups of certain
enzymes.
• Ex: Porphyrin synthesis and carbohydrate metabolism.
• Also effects membrane permeability and potassium leakage from
erythrocytes exposed to lead.
25. • Harmful effect of lead:-
• 1- Lead also interferes with DNA transcription, enzymes that help in the synthesis
of vitamin D, and enzymes that maintain the integrity of the cell membrane.
• 2- Lead interferes with metabolism of bones and teeth.
• 3- Lead alters the permeability of blood vessels and collagen synthesis
• 4- Lead may also be harmful to the developing immune system, causing
production of excessive inflammatory proteins.
26. • 5- Lead exposure has also been associated with a decrease in activity of
immune cells such as PMN leukocytes.
• 6- Lead also interferes with the normal metabolism of calcium in cells and
causes it to build up within them.
• 7- Lead also inhibits the enzyme ferrochelatase, and in turn inhibits RBC
synthesis and leads to anemia.
• 8- Lead interferes with the release of neurotransmitters, glutamate, a
neurotransmitter important in many functions including learning.
27. Signs and symptoms
• Lead poisoning can cause a variety of symptoms and signs which vary
depending on the individual and the duration of lead exposure.
• Symptoms from exposure to organic lead, which is probably more toxic than
inorganic lead
28. Inorganic lead
• Abdominal colic
• Obstinate constipation
• Loss of appetite
• Blue line on the gums
• Stippling of red cells
• Anaemia
• Wrist drop
• Foot drop
29. • Renal system: The toxic effect of lead causes nephropathy and may cause Fanconi
syndrome.
• Cardiovascular system: Evidence suggests lead exposure is associated with high
blood pressure, coronary heart disease, heart rate variability, and death from stroke.
• Reproductive system: Lead affects both the male and female reproductive systems.
In men, when blood lead levels exceed 40 μg/dL, sperm count is reduced and
changes occur in volume of sperm, their motility, and their morphology.
33. Diagnosis
• History: lead exposure
• Clinical features: Loss of appetite ,Persistant headache,Abdominal
cramps,Vomiting ,Weight loss, Constipation, Anemia, Irritability, Learning
disabilities,Joint or muscular pains, blue lines on gums, Behavior problems.
• ( In children-hearing loss, delayed growth, drowsiness, clumsiness, or loss of
new abilities, especially speech skills)
34. • Laboratory tests:
• CPU- useful ścreening test (< 150 mcg/lt- in unexposed)
• Amino levulinic acid in urine (ALAU): >5mg/lt
• Lead in blood and urine:
In urine : over 0.8 mg/lt
In blood : 70 mcg/100ml
• Basophilic stipling of RBC- sensitive parameter.
35. Preventive Measures
• 1- Substitution : where possible lead compounds to be substituted by less
toxic materials
• 2- Isolation : all processes which give rise to harmful concentration of lead
dust or fumes should be enclosed and segregated.
• 3-Local exhaust ventilation: adequate ventilation to remove fumes and dust.
36. Preventive Measures
• 4- Personal protection: workers should be protected by approved respirators
• 5- Good house keeping: essential where lead dust is present.
Floors, benches, machines should be kept clean
wet sweeping.
37. Preventive Measures
• 6- Working atmosphere: 2mg per 10 cu. metres of air.
• 7- Periodic examinatioin of workers
• 8- Personal hygiene
• 9- Health education
38. Management
• Treatment for lead poisoning begins with removing the sources of lead and
providing balanced nutrition.
• Saline purge will remove unabsorbed lead from the gut.
• The use of d-penicillamine has been reported to be effective.
• CHELATION THERAPY Chelating agents like Ca-EDTA.
• Lead levels greater than 45 mcg/dL of blood - Ethylenediamine tetraacetic
acid (EDTA).
• Lead poisoning is notifiable and compensatable disease.
