LEAD POISONING- A SERIOUS THREAT TO HEALTH Lead poisoning is a type of metal poisoning caused by lead in the body.[2]The brain is the most sensitive.[2]Symptoms may include abdominal pain, constipation, headaches, irritability, memory problems, inability to have children, and tingling in the hands and feet.[1] It causes almost 10% of intellectual disability of otherwise unknown cause and can result in behavioral problems.[2] Some of the effects are permanent.[2] In severe cases anemia, seizures, coma, or deathmay occur.[1][2] Lead poisoning Synonyms Plumbism, colica pictorum, saturnism, Devon colic, painter's colic An X ray demonstrating the characteristic finding of lead poisoning in humans—dense metaphyseal lines. Specialty Toxicology Symptoms Intellectual disability, abdominal pain, constipation, headaches, irritability, memory problems, inability to have children, tingling in the hands and feet[1][2] Complications Anemia, seizures, coma[1][2] Causes Exposure to lead via contaminated air, water, dust, food, consumer products[2] Risk factors Being a child[2] Diagnostic method Blood lead level[2] Differential diagnosis Iron deficiency anemia, malabsorption, anxiety disorder, polyneuropathy[3] Prevention Removing lead from the home, improved monitoring in the workplace, laws that ban lead in products[2][4][5][6] Treatment Chelation therapy[4] Medication Dimercaprol, edetate calcium disodium, succimer[7] Deaths 853,000 (2013)[2] Exposure to lead can occur by contaminated air, water, dust, food, or consumer products.[2] Children are at greater risk as they are more likely to put objects in their mouth such as those that contain lead paint and absorb a greater proportion of the lead that they eat.[2] Exposure at work is a common cause of lead poisoning in adults with certain occupations at particular risk.[7]Diagnosis is typically by measurement of the blood lead level.[2] The Centers for Disease Control (US) has set the upper limit for blood lead for adults at 10 µg/dl (10 µg/100 g) and for children at 5 µg/dl.[8][9] Elevated lead may also be detected by changes in red blood cellsor dense lines in the bones of children as seen on X-ray.[4] Lead poisoning is preventable.[2] This includes by individual efforts such as removing lead-containing items from the home,[5] workplace efforts such as improved ventilation and monitoring,[6]and nationwide policies such as laws that ban lead in products such as paint and gasoline, reduce allowable levels in water or soil, and provide for cleanup of contaminated soil.[2][4] The major treatments are removal of the source of lead and the use of medications that bind lead so it can be eliminated from the body, known as chelation therapy.[4]Chelation therapy in children is recommended when blood levels are greater than 40–45 µg/dl.[4][10]Medications used include dimercaprol, edetate calcium disodium, and succimer.[7] In 2013 lead is believed to have resulted in 853,000 deaths.[2] It occurs most commonly in the developing world.[2]Those who are poor are at greater risk.[2]Lead is believed to result in 0.6% of the world's disease burden.[5] People have been mining and using lead for thousands of years.[4] Descriptions of lead poisoning date to at least 2000 BC,[4] while efforts to limit lead's use date back to at least the 16th century.[5]Concerns for low levels of exposure begin in the 1970s with there being no safe threshold for lead exposure.[2][4] Classification Classically, "lead poisoning" or "lead intoxication" has been defined as exposure to high levels of lead typically associated with severe health effects.[11] Poisoning is a pattern of symptoms that occur with toxic effects from mid to high levels of exposure; toxicity is a wider spectrum of effects, including subclinical ones (those that do not cause symptoms).[12] However, professionals often use "lead poisoning" and "lead toxicity" interchangeably, and official sources do not always restrict the use of "lead poisoning" to refer only to symptomatic effects of lead.[12] The amount of lead in the blood and tissues, as well as the time course of exposure, determine toxicity.[13] Lead poisoning may be acute (from intense exposure of short duration) or chronic (from repeat low-level exposure over a prolonged period), but the latter is much more common.[14] Diagnosis and treatment of lead exposure are based on blood lead level (the amount of lead in the blood), measured in micrograms of lead per deciliter of blood (μg/dL). Urine lead levels may be used as well, though less commonly. In cases of chronic exposure lead often sequesters in the highest concentrations first in the bones, then in the kidneys. If a provider is performing a provocative excretion test, or "chelation challenge", a measurement obtained from urine rather than blood is likely to provide a more accurate representation of total lead burden to a skilled interpreter.[15] The US Centers for Disease Control and Prevention and the World Health Organization state that a blood lead level of 10 μg/dL or above is a cause for concern; however, lead may impair development and have harmful health effects even at lower levels, and there is no known safe exposure level.[16][17]Authorities such as the American Academy of Pediatrics define lead poisoning as blood lead levels higher than 10 μg/dL.[18] Lead forms a variety of compounds and exists in the environment in various forms.[19] Features of poisoning differ depending on whether the agent is an organic compound (one that contains carbon), or an inorganic one.[20] Organic lead poisoning is now very rare, because countries across the world have phased out the use of organic lead compounds as gasoline additives, but such compounds are still used in industrial settings.[20] Organic lead compounds, which cross the skin and respiratory tract easily, affect the central nervous system predominantly.[20] Signs and symptoms Symptoms of lead poisoning. Lead poisoning can cause a variety of symptoms and signs which vary depending on the individual and the duration of lead exposure.[21][22]Symptoms are nonspecific and may be subtle, and someone with elevated lead levels may have no symptoms.[23]Symptoms usually develop over weeks to months as lead builds up in the body during a chronic exposure, but acute symptoms from brief, intense exposures also occur.[24] Symptoms from exposure to organic lead, which is probably more toxic than inorganic lead due to its lipid solubility, occur rapidly.[25] Poisoning by organic lead compounds has symptoms predominantly in the central nervous system, such as insomnia, delirium, cognitive deficits, tremor, hallucinations, and convulsions.[20] Symptoms may be different in adults and children; the main symptoms in adults are headache, abdominal pain, memory loss, kidney failure, male reproductive problems, and weakness, pain, or tingling in the extremities.[26] Early symptoms of lead poisoning in adults are commonly nonspecific and include depression, loss of appetite, intermittent abdominal pain, nausea, diarrhea, constipation, and muscle pain.[27] Other early signs in adults include malaise, fatigue, decreased libido, and problems with sleep.[21] An unusual taste in the mouth and personality changes are also early signs.[28] In adults, symptoms can occur at levels above 40 μg/dL, but are more likely to occur only above 50–60 μg/dL.[21]Symptoms begin to appear in children generally at around 60 μg/dL.[5]However, the lead levels at which symptoms appear vary widely depending on unknown characteristics of each individual.[29] At blood lead levels between 25 and 60 μg/dL, neuropsychiatric effects such as delayed reaction times, irritability, and difficulty concentrating, as well as slowed motor nerve conduction and headache can occur.[30] Anemia may appear at blood lead levels higher than 50 μg/dL.[27] In adults, abdominal colic, involving paroxysms of pain, may appear at blood lead levels greater than 80 μg/dL.[22] Signs that occur in adults at blood lead levels exceeding 100 μg/dL include wrist drop and foot drop, and signs of encephalopathy (a condition characterized by brain swelling), such as those that accompany increased pressure within the skull, delirium, coma, seizures, and headache.[31] In children, signs of encephalopathy such as bizarre behavior, discoordination, and apathy occur at lead levels exceeding 70 μg/dL.[31] For both adults and children, it is rare to be asymptomatic if blood lead levels exceed 100 μg/dL.[22] Acute poisoning In acute poisoning, typical neurological signs are pain, muscle weakness, numbness and tingling, and, rarely, symptoms associated with inflammation of the brain.[26] Abdominal pain, nausea, vomiting, diarrhea, and constipation are other acute symptoms.[32] Lead's effects on the mouth include astringency and a metallic taste.[32]Gastrointestinal problems, such as constipation, diarrhea, poor appetite, or weight loss, are common in acute poisoning. Absorption of large amounts of lead over a short time can cause shock (insufficient fluid in the circulatory system) due to loss of water from the gastrointestinal tract.[32] Hemolysis (the rupture of red blood cells) due to acute poisoning can cause anemia and hemoglobin in the urine.[32] Damage to kidneys can cause changes in urination such as decreased urine output.[32]People who survive acute poisoning often go on to display symptoms of chronic poisoning.[32] Chronic poisoning Chronic poisoning usually presents with symptoms affecting multiple systems,[20] but is associated with three main types of symptoms: gastrointestinal, neuromuscular, and neurological.[26]Central nervous system and neuromuscular symptoms usually result from intense exposure, while gastrointestinal symptoms usually result from exposure over longer periods.[32]Signs of chronic exposure include loss of short-term memory or concentration, depression, nausea, abdominal pain, loss of coordination, and numbness and tingling in the extremities.[28][unreliable medical source?] Fatigue, problems with sleep, headaches, stupor, slurred speech, and anemia are also found in chronic lead poisoning.[26] A "lead hue" of the skin with pallor and/or lividity is another feature.[33][34] A blue line along the gum with bluish black edging to the teeth, known as a Burton line, is another indication of chronic lead poisoning.[35]Children with chronic poisoning may refuse to play or may have hyperkineticor aggressive behavior disorders.[26]Visual disturbance may present with gradually progressing blurred vision as a result of central scotoma, caused by toxic optic neuritis.[36] Effects on children As lead safety standards become more stringent, fewer children in the US are found to have elevated lead levels. A woman who has elevated blood lead levels during pregnancy is at greater risk of a prematurely birth or with a low birth weight.[37] Children are more at risk for lead poisoning because their smaller bodies are in a continuous state of growth and development.[38] Lead is absorbed at a faster rate compared to adults, which causes more physical harm than to older people. Furthermore, children, especially as they are learning to crawl and walk, are constantly on the floor and therefore more prone to ingesting and inhaling dust that is contaminated with lead.[39] The classic signs and symptoms in children are loss of appetite, abdominal pain, vomiting, weight loss, constipation, anemia, kidney failure, irritability, lethargy, learning disabilities, and behavioral problems.[40] Slow development of normal childhood behaviors, such as talking and use of words, and permanent intellectual disability are both commonly seen. Although less common, it is possible for fingernails to develop leukonychia striata if exposed to abnormally high lead concentrations.[41] By organ system Lead affects every one of the body's organ systems, especially the nervous system, but also the bones and teeth, the kidneys, and the cardiovascular, immune, and reproductive systems.[42]Hearing loss and tooth decay have been linked to lead exposure,[43] as have cataracts.[44] Intrauterine and neonatal lead exposure promote tooth decay.[45][46][47][48][49][50][51] Aside from the developmental effects unique to young children, the health effects experienced by adults are similar to those in children, although the thresholds are generally higher.[52] Kidneys Kidney damage occurs with exposure to high levels of lead, and evidence suggests that lower levels can damage kidneys as well.[53] The toxic effect of lead causes nephropathy and may cause Fanconi syndrome, in which the proximal tubular function of the kidney is impaired.[54] Long-term exposure at levels lower than those that cause lead nephropathy have also been reported as nephrotoxic in patients from developed countries that had chronic kidney disease or were at risk because of hypertension or diabetes mellitus.[55]Lead poisoning inhibits excretion of the waste product urate and causes a predisposit

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