Children 6 to 10 years old in the same community are observed by the local physician to be doing poorly in school, which has been attributed to behavioral problems. Their parents state that these children have poor appetites, complain of nausea, and have frequent headaches. On physical examination, they have decreased sensation to touch over the lower extremities. They exhibit loss of fine motor control of movement and have a slightly ataxic gait. A representative CBC shows hemoglobin of 11.8 g/dL, hematocrit of 35.2%, MCV of 82 mm3, platelet count of 282,300/ mm3, and WBC count of 4745/ mm3. Examination of the peripheral blood smear shows basophilic stippling of the RBCs. Excessive chronic ingestion of which of the following substances is most likely to explain these findings?
Lead poisoning is mainly manifested by neurologic disorders, particularly in children. Lead absorption is enhanced by zinc deficiency; zinc is a trace metal. Lead inhibits heme incorporation into hemoglobin, leading to increased amounts of zinc protoporphyrin with anemia. Cadmium is a heavy metal associated with toxicity to the gastrointestinal tract, kidneys, and lungs. Copper is a trace metal that is unlikely to cause toxicity from environmental sources, although copper accumulation can occur with Wilson disease. Acute iron poisoning is associated with gastrointestinal, renal, and CNS toxicities. Nickel jewelry may cause skin rash; inhaled nickel produces respiratory problems.
Cadmium
Copper
Iron
Lead
Blood