Iron-restricted microcytic anemia vs Globin or heme-synthesis microcytic anemia
How to tell Iron-restricted microcytic anemia and Globin or heme-synthesis microcytic anemia apart when a board question makes them look alike.
Iron deficiency is ferritin-low/TIBC-high; chronic disease is ferritin-high/TIBC-low; thalassemia is globin problem; sideroblastic/lead are heme-synthesis problems with iron present.
Side by side
Iron deficiency has low ferritin, high TIBC, high RDW, koilonychia, pica, and chronic blood loss; anemia of chronic disease has low iron with low TIBC and normal/high ferritin.
Thalassemia has low MCV with normal iron and target cells; sideroblastic anemia has ring sideroblasts and high iron; lead poisoning has basophilic stippling and neurologic/GI clues.
Iron deficiency lacks substrate for heme; inflammation traps iron in macrophages through hepcidin, limiting iron availability.
Thalassemia reduces globin synthesis; sideroblastic anemia traps iron in mitochondria; lead inhibits heme synthesis enzymes.
Low ferritin and high TIBC support iron deficiency; high ferritin with low TIBC supports anemia of chronic disease.
Normal iron studies with abnormal electrophoresis support thalassemia; ring sideroblasts/high iron support sideroblastic anemia; basophilic stippling supports lead.
The trap
All are microcytic, so iron studies, RDW, smear, and exposure history decide the cause.
The repair move
For microcytosis, do not stop at low MCV; sort iron stores, inflammation, globin production, and heme synthesis.
Try a free question
CoreA patient has microcytic anemia, low ferritin, high TIBC, increased RDW, pica, and occult gastrointestinal blood loss. Which diagnosis is most likely?
Show answer and explanation
Answer: A. Iron deficiency anemia. Low ferritin with high TIBC and chronic blood loss points to iron deficiency anemia.
Why the other choices are tempting
- B. Anemia of chronic disease has low TIBC and normal or high ferritin.
- C. Thalassemia trait usually has normal iron studies and target cells.
- D. Sideroblastic anemia has ring sideroblasts and increased iron.
- E. Lead poisoning has exposure clues, neurologic/GI symptoms, and basophilic stippling.
Flashcards
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What iron studies point to iron deficiency anemia?
Low ferritin with high TIBC points to iron deficiency anemia.
What iron studies point to anemia of chronic disease?
Low serum iron with low TIBC and normal or high ferritin points to anemia of chronic disease.
Quick answers
What is the fastest way to tell Iron-restricted microcytic anemia from Globin or heme-synthesis microcytic anemia?
Iron deficiency is ferritin-low/TIBC-high; chronic disease is ferritin-high/TIBC-low; thalassemia is globin problem; sideroblastic/lead are heme-synthesis problems with iron present.
What is the key clue for Iron-restricted microcytic anemia?
Iron deficiency has low ferritin, high TIBC, high RDW, koilonychia, pica, and chronic blood loss; anemia of chronic disease has low iron with low TIBC and normal/high ferritin.
What is the key clue for Globin or heme-synthesis microcytic anemia?
Thalassemia has low MCV with normal iron and target cells; sideroblastic anemia has ring sideroblasts and high iron; lead poisoning has basophilic stippling and neurologic/GI clues.
What is the common trap with Iron-restricted microcytic anemia vs Globin or heme-synthesis microcytic anemia?
All are microcytic, so iron studies, RDW, smear, and exposure history decide the cause.