injuries poisoning
Lead Poisoning
Diagnosis of Lead Poisoning
Lead levels in capillary or whole blood X-rays of abdomen Sometimes x-rays of long bones in children with suspected chronic exposure Lead poisoning is suspected in patients with characteristic symptoms. However, because symptoms are often nonspecific, diagnosis of lead poisoning is often delayed. Evaluation includes complete blood count and measurement of serum electrolytes, bloodureanitrogen (BUN), serum creatinine, plasma glucose, and whole blood lead levels (PbBs). An abdominal x-ray should be taken to look for lead particles, which are radiopaque. X-rays of long bones are taken in children. Horizontal, metaphyseal lead bands representing lack of bone remodeling and increased calcium deposition in the zones of provisional calcification in children’s long bones are somewhat specific for poisoning with lead or other heavy metals but are insensitive. Normocytic or microcytic anemia suggests lead toxicity, particularly when the reticulocyte count is elevated or red blood cell basophilic stippling occurs; however, sensitivity and specificity are limited. Diagnosis is definitive if PbB is≥5 mcg/dL (0.24 micromol/L). Because measuring PbB is not always possible and can be expensive, other preliminary or screening tests for lead poisoning can be used. Capillary blood testing for lead is accurate, inexpensive, and quick. All positive tests should be confirmed with PbB. The erythrocyte protoporphyrin (also called zinc protoporphyrin or free erythrocyte protoporphyrin) test is often inaccurate and now is seldom used. 3.5 mcg/dL (0.17 micromol/L) should be assessed clinically and, if necessary, with testing for nutritional and vitamin deficiencies (eg, Iron Deficiency , Provocative urine metal testing for lead and other metals in which chelation agents (eg, dimercaptosuccinic acid, dimercaptopropane sulfonic acid, calcium disodium edetate) are given to the patient and then urinary levels of excreted metals are measured has not been scientifically validated, has no shown benefit, and may be harmful in the assessment and treatment of patients in whom there is concern for metal poisoning. 