Lead poisoning may occur in children or adults due to accidental or occupational ingestion. In children, the following are the main sources of lead poisoning:Chewing of lead-containing furniture items, toys or pencils.Eating of lead paint flakes from walls.In adults, the sources are as follows:Occupational exposure to lead during spray painting, recycling of automobile batteries (lead oxide fumes), mining, and extraction of lead.Accidental exposure by contaminated water supply, house freshly coated with lead paint and sniffing of lead-containing petrol (hence unleaded petrol introduced as fuel).Lead is absorbed through the gastrointestinal tract or lungs. The absorbed lead is distributed in two types of tissuesa) Bones, teeth, nails and hair representing a relatively harmless pool of lead. About 90% of absorbed lead accumulates in the developing metaphysis of bones in children and appears as areas of increased bone densities ('lead lines') on X-ray. Lead lines are also seen in the gingiva. b) Brain, liver, kidneys and bone marrow accumulate the remaining 10% lead which is directly toxic to these organs.It is excreted kidneys. Lead toxicity occurs in the following organs predominantly:1. Nervous system: The changes are as under:In children, lead encephalopathy; edema of the brain, flattening of gyri and compression of ventricles.In adults, demyelinating peripheral motor neuropathy which typically affects radial and peroneal nerves resulting in wristdrop and footdrop respectively.2. Hematopoietic system: The changes in the blood are quite characteristic:Microcytic hypochromic anemia due to inhibition of two enzymes: delta-aminolevulinic acid dehydrogenase required for haem synthesis, and through inhibition of ferroketolase required for incorporation of ferrous iron into the porphyrinring.Prominent basophilic stippling of erythrocytes. 3. Kidneys: Lead is toxic to proximal tubular cells of the kidney and produces lead nephropathy characterized by the accumulation of intranuclear inclusion bodies consisting of the lead-protein complex in the proximal tubular cells.4. Gastrointestinal tract: Lead toxicity in the bowel manifests as acute abdomen presenting as lead colic. Signs and symptoms of lead poisoning in children include: Developmental delay Learning difficulties Irritability Loss of appetite Weight loss Sluggishness and fatigue Abdominal pain Vomiting Constipation Hearing loss Seizures Eating things, such as paint chips, that aren't food (pica) Signs and symptoms in adults might include: High blood pressure Joint and muscle pain Difficulties with memory or concentration Headache Abdominal pain Mood disorders Reduced sperm count and abnormal sperm Miscarriage, stillbih or premature bih in pregnant women HARSH MOHAN Textbook of pathology 6th edition pg no 240-241