A three year old child was evaluated for abdominal pain and anorexia by a physician. CBC reveals Hgb of 9.8 g/dL and basophilic stippling of the RBCs.
The physician should order further tests to check for poisoning from?
Patient presents slightly anemic with a hemoglobin of 9.8 g/dL (Reference children: 11.0-14.5 g/dL). Basophilic stippling is residual ribosomal RNA that can be seen on a wrights stain. It can be observed in some Myelodysplastic disorders, sideoblastic anemia, megaloblastic anemia, arsenic poisoning, and thalassemia.
The correct answer is lead poisoning. Lead interferes with heme synthesis. It inhibits ALA dehydratase otherwise known as porphobilinogen synthase (PBG) which stops heme synthesis. Other findings consistent with lead poisoning would be a microcytic, and hypochromic RBC.
Elevated lead levels in a whole blood lead test is diagnostic. Urine D-ALA and RBC zinc protoporphyrin are also useful assays.
Children are at more of risk for lead poisoning because they are in a continuous state of growth and development and lead is absorbed at a faster rate than in adults. The classical signs in children are loss of appetite, abdominal pain, vomiting, weight loss, constipation, anxiety, kidney failure, irritability, growth retardation, and behavior problems. Sometimes permanent intellectual disability can be seen. As you can see lead poisoning can affect multiple organ systems.
Lead can come from from anywhere, the most common exposure route in adults is occupational exposure. Lead can also be found in food if the food is grown in soil that is high in lead. It can be found in paint, in the soil, and in water sources.
BOC Study Guide 5th Edition, ASCP, pgs. 115,138