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  1. 1. Lead Poisoning Presentor : Dr.Anurag Fursule Moderator : Dr. Malini www.dnbpediatrics.com
  2. 2. Introduction • Lead has no essential role in the human body. • Lead poisoning accounts for about 0.6% of the global burden of disease. (WHO, 2009). • entirely preventable. • one of the most common and best-recognized childhood diseases of toxic environmental origin. • Lead exposure is estimated to contribute to 6,00,000 new cases of children with intellectual disabilities every year, it says • Overall, 99 per cent of the affected children live in low and middle income countries.(BLL 10x-20x) www.dnbpediatrics.com
  3. 3. Public Health History • Blood Lead Level (BLL): CDC,AAP, and numerous other national and international Organizations consider a BLL of 10 μg/dL or greater as a level of concern for public health purposes. • BLL is the gold standard for determining health effects. • However, lead toxicity occurs below this threshold, and no safe level has been identified www.dnbpediatrics.com
  4. 4. • Between 1976 and 1980, more than 85% of preschool children in the USA had BLLs of 10 μg/dL or higher; 98% of African-American preschoolers fulfilled this criterion. • So govt took following measure :(1) the elimination of the use of tetraethyl leaded gasoline (2) the banning of lead-containing solder to seal food- and beverage-containing cans (3) the application of a federal rule that limited the amount of lead allowed in paint intended for household use to less than 0.06% by weight. www.dnbpediatrics.com
  5. 5. • Surveillance by the CDC has shown that the prevalence of elevated BLLs (≥ 10 ?g/dL) has declined markedly, and by 2004 it was below 1.5% in all preschoolers. • Risk factors: -preschool age -low socioeconomic status -living in older housing(built primarily before 1960; urban location) -African-American race -recent immigrants from less wealthy countries, including adoptees. www.dnbpediatrics.com
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  8. 8. Metabolism Hand to mouth activity of children Gut..good absorption if small particle size , in empty stomach , iron and calcium deficient diet Poor absorption if large paint chips, presence of iron and calcium After absorption: 1)Bones,teeth,hair : may reside for years 2)Blood: (a)RBC:97% (b) Serum: negligible but may enter cell & induce toxicity www.dnbpediatrics.com
  9. 9. • Lead binds to enzymes, particularly those with available sulfhydryl groups, changing the contour and diminishing function. •Inhibition of ferrochelatase •Accumalation of protoporhyrin •Hb synthesis inhibition •Competition with calcium •CBP have higher affinity for lead •Abnormal inter/intracellular signalling(e.g. Neurotransmittor release •Prevention of development of normal tertiary brain structure,normal neuronal pruning process •Permanent neuronal disability:ADHD www.dnbpediatrics.com
  10. 10. Clinical Symptoms • Fatal dose: lead acetate – 20gms lead carbonate – 30 gms • Fatal period: 1-2 days. • Acute lead poisoning: -rare -GI: metallic taste,diarrhea,constipation,intestinal colic -CNS: formication,convulsion,insomnia,coma -CVS: circulatory collapse -blood level > 150mg/dl www.dnbpediatrics.com
  11. 11. Chronic lead poisoning(plumbism) • Clinical features: • A. CNS (BLL>100mcg/dL) -worsening cerebral edema -raised ICP -headache -abnormal mentation -encephalopathy : mimics tuberculous meningitis -lethargy -CN palsy -papilledema -seizure -coma -Sudden death : RLN palsy, phrenic nerve palsy www.dnbpediatrics.com
  12. 12. • Neuromuscular effects and peripheral neuropathy : -Calf muscle pain -Easy fatigue ability -Paralysis of extensor muscle forearm and hand(dominant hand)(d/t interference with resynthesis of phosphocreatinine) -Wrist drop, rarely foot drop • Developmental dysfunction: -regression of milestone in children after 12-18 months of normal development -ADHD blood levels- 30-50 mg/dL -poor IQ www.dnbpediatrics.com
  13. 13. • Hematological : -initially polychromasia, polycythemia, reticulocytosis, basophilic stippling -hypochromic microcytic anemia -decreased osmotic fragility RBC • Renal -oligouria -hematuria -hyperuricemia -fanconi syndrome -cast in urine www.dnbpediatrics.com
  14. 14. • GI disturbance : -nausea , vomiting , anorexia -metallic taste -lead line on gum : burtonian line -abdominal colics. www.dnbpediatrics.com
  15. 15. Diagnosis • In emergency diagnosis of lead poisoning may be considered in presence of 2 or more of following: 1)Hypochromic : microcytic anemia 2)Abdominal x rays: radio opaque forign bodies in gut, bone x rays:broad dense bands at metaphyses. 3)glycosuria,aminoaciduria,hypophosphatemia 4)Coproprphyrinuria : 60-280mg/24hrs 5)Urinary ALA estimation: several fold increased 2mg/24 hrs 6)Raised ICP,CSF protein increased with mild pleocytosis. 7)Urine lead content: normally < 0.08mg/litre(lead mobilization test) www.dnbpediatrics.com
  16. 16. •Experimentally, the method of x-ray fluorescence (XRF) allows direct and noninvasive assessment of bone lead stores(measurable after years of exposure when blood level may still be low). •XRF methodology is not available for clinical use in children. www.dnbpediatrics.com
  17. 17. • Screening • Interpretation of Blood Lead Levels: -A screening value at or above 2 mcg/dL is consistent with exposure and requires a second round of testing for a diagnosis and to determine the appropriate intervention. • A confirmed venous BLL of 45 mcg/dL or higher requires prompt chelation therapy. www.dnbpediatrics.com
  18. 18. Erythrocyte Protoporphyrin • Because BLLs reflect recent ingestion or redistribution from other tissues but do not necessarily correlate with the body burden of lead or lead toxicity in an individual child, tests of lead effects also may be useful. • After several weeks of lead accumulation and a BLL higher than 20 mcg/dL, increases in EP values to more than 35 mcg/dL may occur. • An elevated EP value that cannot be attributed to iron deficiency or recent inflammatory illness is both an indicator of lead effect and a useful means of assessing the success of the treatment; the EP level will begin to fall a few weeks after successful interventions that reduce lead ingestion and increase lead excretion. • Because EP is light sensitive, whole blood samples should be covered in aluminum foil (or equivalent) until analyzed. www.dnbpediatrics.com
  19. 19. Treatment www.dnbpediatrics.com
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  22. 22. • Bone stores cannot be depleted easily • cognitive/behavioral effects of lead may be irreversible • So mainstay in treatment it is to prevent exposure. • The main components in the effort to eliminate lead poisoning are : 1. identification and elimination of environmental sources of lead exposure 2. behavioral modification to reduce nonnutritive hand-to-mouth activity 3. dietary counseling to ensure sufficient intake of the essential elements calcium and iron www.dnbpediatrics.com
  23. 23. Preventing Lead Poisoning • The Centers for Disease Control suggest the following guidelines: • Parents should ask a doctor to test their child, if there is concern about children being exposed to lead. • If you live in a house or apartment built before 1978, talk to your state or local health department about testing paint and dust from your home for lead. This is especially important if young children live with you or visit you. • Wash your children's hands after they play outside, before eating and going to bed. • Restrict where your children play. Don't let them play near major roadways or bridges • Prepare meals that are high in iron and calcium. A nutritious diet helps prevent lead absorption in your children's bodies. www.dnbpediatrics.com
  24. 24. • Damp-mop floors, damp-wipe surfaces, and frequently wash a child’s hands, pacifiers and toys to reduce exposure to lead. • Use only cold water from the tap for drinking, cooking and for making baby formula. Hot water is more likely to contain higher levels of lead. Most of the lead found in household water usually comes from the plumbing in a house, not from the local water supply. • Avoid using home remedies (such as azarcon, greta, pay-loo-ah) and cosmetics (such as kohl, alkohl) that contain lead. • Take basic steps to decrease your exposure to lead (for example, by showering and changing clothes after finishing the task), if you remodel buildings built before 1978, or if your work or hobbies involve working with lead-based products. www.dnbpediatrics.com
  25. 25. Chelation Therapy • Indications: 1. lead encephalopathy 2. nonencephalopathic children, it prevents symptom progression and further toxicity 3. A child with a venous BLL 45 mcg/dL or higher should be treated. www.dnbpediatrics.com
  26. 26. • Principles of treatment: 1. Children with BLLs of 44-70 mcg/dL may be treated with a single drug, preferably DMSA 2. BLLs of 70 mcg/dL or greater require two-drug treatment a. with encephalopathy: Edetate + BAL b. without encephalopathy : edetate + DMSA/BAL 3. These drugs also may increase lead absorption from the gut and should be administered to children in lead-free environments. 4. Repeat chelation is indicated if the BLL rebounds to 45 mcg/dL or higher. 5. Children with initial BLLs higher than 70 mcg/dL are likely to require more than one course 6. A minimum of 3 days between courses is recommended to prevent treatment-related toxicities, especially in the kidney. www.dnbpediatrics.com
  27. 27. • With successful intervention, BLLs decline, with the greatest fall in BLL occurring in the first 2 mo after therapy is initiated. • Subsequently the rate of change in BLL declines slowly so that by 6-12 mo after identification, the BLL of the average child with moderate lead poisoning (BLL >20 mcg/dL) will be 50% lower. • Children with more markedly elevated BLLs may take years to reach the CDC threshold of concern, 10 mcg/dL, even if all sources of lead exposure have been eliminated, behavior has been modified, and nutrition has been maximized. • Early screening remains the best way of avoiding and therefore obviating the need for the treatment of lead poisoning www.dnbpediatrics.com
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