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Introduction to lead What is lead poisoning Classification of lead poisoning Sources of exposure Who is at risk Pathophysiology Harmful effect of lead Signs and symptoms Diagnosis Treatment Prevention conclusion Contents
Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. It is sometimes found free in nature, Although lead makes up only about 0.0013% of the earth's crust, it is not considered to be a rare element since it is easily mined and refined. Introduction about Lead
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, colicaPictonum or saturnism What is lead poisoning???
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). How is it classified??
Acute poisoning:- In acute poisoning, typical neurological signs are pain, muscle weakness. Gastrointestinal problems, such as diarrhea, 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.
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.
What are the Normal levels of lead?? Adults: Less than 20 micrograms/dL of lead in the blood Children: Less than 10 micrograms/dL of lead in the blood
How can the human be exposed to lead?? 1- Occupational exposure:- is the main cause of lead poisoning in adults, as in lead miners and smelters, plumbers glass manufacturers, construction workers …etc. 2- 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.
3- Soil:- is the main cause of lead poisoning in the agricultural areas. By eating food grown in an contaminated soil. 4- Water:- Lead from the soil or atmosphere can end up in surface water and groundwater. It is also potentially in drinking water.
5- Lead containing products:- Like plastic toys, bottles, cans……etc. 6- 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.
All children under the age of 6 years old. People living in old houses are at great risk. People work in industries. Pregnant woman & developing baby. Who is at high risk?
Lead may be taken in through direct contact with mouth, nose, and eyes, and through breaks in the skin. Organic lead can be absorbed through the skin to a limit extend while The main sources of absorption of inorganic lead are from ingestion and inhalation. 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. Physiopathology
In adults, 94% of absorbed lead is deposited in the bones and teeth, but 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.
Distribution of lead:- 95% long bones. Binds into matrix. Released during osteolysis. 4% brain,liver, kidneys. 1% blood. Crosses placenta, foetal BBB is open
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.
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.
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 due to its lipid solubility, occur rapidly. Poisoning by organic lead compounds has symptoms predominantly in the central nervous system, such as insomnia, delirium, cognitive deficits, tremor, hallucinations, and convulsions. Symptoms may be different in adults and children
the main signs and symptoms in adults are :- 1- headache 2-memory loss 3- male reproductive problems 4- weakness, pain in the extremities 5- malaise 6- problems with sleep.
The classic signs and symptoms in children are:- 1- loss of appetite 2- vomiting 3- weight loss 4- constipation 5- anemia 6- Irritability 7- learning disabilities 8- behavior problems. 9- Children may also experience hearing loss, delayed growth, drowsiness, clumsiness, or loss of new abilities, especially speech skills
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. Complications
A pregnant woman's elevated blood lead level can lead to miscarriage, prematurity, low birth weight. Nervous system: Lead affects the peripheral nervous system (especially motor nerves) and the central nervous system. Peripheral nervous system effects are more prominent in adults and central nervous system effects are more prominent in children. Lead causes the axons of nerve cells to degenerate and lose their myelin coats. Lead also causes bone and teeth decay.
Blood film examination may reveal basophilic stippling of red blood cells Exposure to lead also can be evaluated by measuring erythrocyte protoporphyrin (EP) in blood samples Examination of hair, nails are also introduced. Fecal and urine examination. Diagnosis
Presence of lines called lead lines at the metaphysis in the long bones of growing children, especially around the knees.
Treatment Treatment for lead poisoning begins with removing the sources of lead and providing balanced nutrition. CHELATION THERAPY Chelating agents are used for severe lead poisoning.
EDTA THERAPY Doctors treat lead levels greater than 45 mcg/dL of blood with a chemical called ethylenediaminetetraacetic acid (EDTA). Depending on your lead level, you may need more than one treatment. - In such severe cases, however, it may not be possible to reverse damage that has already occurred.
Prevention In most cases, lead poisoning is preventable; the way to prevent it is to prevent exposure to lead. Prevention strategies can be divided into individual (measures taken by a family), preventive medicine (identifying and intervening with high-risk individuals), and public health (reducing risk on a population level). 1- Substitution.
2- Isolation 3- Good house keeping 4- Periodic examination of workers
5- Working atmosphere 6- Personal hygiene 7- Health education
8- Local exhaust ventilation 9- Personal protection
Lead is a relatively rare element. Known as one of the top six primary pollutants which is also a metal, we should take precautions to make sure we don’t come in contact with lead. Exposure to lead causes lead poisoning, which depending on the level of exposure leads to diseases, brain damage, kidney damage, death, and even more. Lead poisoning can be prevented and detected as well. To prevent children from coming in contact with lead, parents or guardians should make sure they play in safe, clean areas and they do not put old toys, paint, or any metals in their mouths. Adults should be careful at workplaces such as car battery plants, radiator shops, construction trades, or jobs that handle ammunition because work clothes or materials that are brought home may be contaminated with lead. These are just some of the many ways that humans can come in contact with lead and that we should avoid. In many cases, there are no visible symptoms of elevated blood-lead levels or lead poisoning. The only way to be completely sure if one has lead poisoning is with a quick and easy blood test. The main treatment for lead poisoning is to stop the exposure as soon as possible or in some cases medications are used to lower blood-lead levels. Conclusion
REFERENCES:- http://www.slideshare.net/glejelen/lead-poisoning-6851059, by Glejelen, on 2nd, march, 2011 http://www.lead.org.au/ BBLP.ppt 3.2Mb, by Dr. Ben Balzer, on 6th, sep. 2000 http://www.mayoclinic.com/health/lead-poisoning/FL00068, by myoclinic staff, on 12th, march 2011 http://en.wikipedia.org/wiki/Lead_poisoning Park’s textbook of preventive and social medicine