2025 – PAGE 287 – HEMATOLOGY & ONCOLOGY
BETA THALASSEMIA
Beta thalassemia is much more important and refers to defects in the genes responsible for production of the beta chains. Like alpha thalassemia, other types of hemoglobin persist in the blood in order to assist with carrying oxygen. You will find elevated levels of fetal hemoglobin (Hgb F) and Hgb A2. Levels of Hgb A1 will be low. There are two genes that are responsible, but there can be THREE forms of beta thalassemia: trait/minor, intermedia, and major/Cooley’s.
- BETA THALASSEMIA TRAIT (AKA BETA THALASSEMIA MINOR): Only one gene is defective. Patients are asymptomatic and may have a mild microcytosis.
- BETA THALASSEMIA INTERMEDIA: Both genes are affected, and there will be a very obvious microcytosis, but it’s not as severe as MAJOR. Patients are able to maintain their hemoglobin in the 6–9 range and may only require an occasional transfusion after an illness.
- BETA THALASSEMIA MAJOR (AKA COOLEY’S ANEMIA): Both genes are affected, and patients have a SEVERE microcytic anemia within the first year of life. They need frequent transfusions and are a setup for complications, often related to hemochromatosis, organomegaly, and gallstones. Patients can also have bone thickening and arterial and venous clots. Blood smears will show microcytosis, target cells, and basophilic stippling. HEMOCHROMATOSIS (AKA HEMOSIDEROSIS) is the deposition of iron into various organs, causing problems such as heart failure, liver failure, and renal disease. It can be hereditary or due to chronic transfusions for other problems, such as beta thalassemia major. Consider this diagnosis in any patient with symptoms of congestive heart failure. Look for other signs, such as polyuria. Treat with DESFEROXIME (“de-iron” – “de-ferrous”).
- PEARLS: If tested on a thalassemia, it will likely be beta thalassemia major. However, if the MCV is low (60–70) and out of proportion with a MILD anemia, pick a thalassemia that is NOT beta thalassemia major. Beta thalassemia major causes SEVERE anemia. Look for microcytosis and target cells on a blood smear.
- IMAGE: www.pbrlinks.com/COOLEYSANEMIA1 (target cells, hypochromia, microcytosis)
- IMAGE: www.pbrlinks.com/COOLEYSANEMIA2 (Basophilic Stippling)
(DOUBLE TAKE) LEAD TOXICITY
Lead toxicity often arises because kids love lead’s sweet taste. Sources of lead toxicity are paint in old homes and dust from home renovations. Because lead blocks iron from being incorporated into heme, lead toxicity can look very much like iron-deficiency anemia (MICROcytic). To differentiate this from iron deficiency, look for BASOPHILIC STIPPLING of RBCs, constipation, neurologic issues and LEAD LINES (obtain imaging of long bones). Check a lead level at 12 and 24 months of age. Even mild elevations (a level of 5–20) can cause neurologic problems with learning and behavior. For mild elevations, make changes in the home and educate the family. For levels > 45, CHELATION therapy is needed for lead poisoning with edetate disodium calcium (EDTA), dimercaprol or d-penicillamine. Always confirm an elevated capillary sample with a VENOUS sample because these are more reflective of RECENT exposure.
PEARL: Iron levels should be normal and TIBC should be normal or low.
IMAGE: (Lead Lines) – www.pbrlinks.com/LEADTOXICITY1
IMAGE: (Basophilic Stippling) – www.pbrlinks.com/LEADTOXICITY2
IMAGE: (Lead Lines) – www.pbrlinks.com/LEADTOXICITY3
MNEMONIC: The treatment for lead is “LEADetate.”