Labs CBC: hypochromic, microcytic anemia with basophilic stippling Hyperuricemia. UA: increased urinary coproporphyria and aminolevulinic acid. Blood lead and free erythrocyte protoporphyrin levels elevated; glycosuria; hypophosphatemia.
Imaging XR, long bones: broad bands of increased density at metaphysis.
Gross Pathology Marked edema of brain; peripheral nerve segmental demyelin-ization.
Acid-fast intranuclear inclusion bodies in renal tubular cells, hepatocytes, and osteoclasts; bone marrow biopsy shows sideroblastic picture.
Treatment Separation from source of exposure; chelation therapy with
CaEDTA or dimercaprol (IM), or by DMSA (succimer) or penicillamine (oral).
Discussion Lead poisoning may be caused by gasoline, eating flaking wall paint (as occurs in pica), or using clay utensils with leaded glaze. Poisoning is more common in summer due to sun exposure with increased circulating porphyrins. Lead binds to disulfide groups, causing denaturation of enzymes, and inhibits ferrochelatase and ^-aminolevulinic acid dehydratase, thereby interfering with iron utilization in heme synthesis.
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