Iron deficiency anemia vs Lead poisoning and sideroblastic anemia
How to tell Iron deficiency anemia and Lead poisoning and sideroblastic anemia apart when a board question makes them look alike.
Iron deficiency is iron missing; lead and sideroblastic anemia are heme-synthesis problems with iron present or misused.
Side by side
Iron deficiency anemia causes microcytosis with low ferritin, high TIBC, high RDW, pica, koilonychia, and chronic blood loss or poor intake.
Lead poisoning causes microcytosis, abdominal pain, neurocognitive symptoms, coarse basophilic stippling, and heme enzyme inhibition; sideroblastic anemia causes ring sideroblasts with increased iron.
Iron stores are depleted, leaving insufficient substrate for heme synthesis.
Lead inhibits ALA dehydratase and ferrochelatase; sideroblastic anemia traps iron in mitochondria because heme synthesis is impaired.
Low ferritin, high TIBC, low serum iron, high RDW, and response to iron support iron deficiency.
Blood lead level and basophilic stippling support lead poisoning; high iron/ferritin and ring sideroblasts support sideroblastic anemia.
The trap
All can be microcytic, so ferritin/TIBC, basophilic stippling, and ring sideroblasts decide the cause.
Watch it explained
The repair move
For microcytic anemia, ask whether iron is absent, poisoned, or trapped in three steps: (1) low ferritin plus high TIBC plus low serum iron plus high RDW equals iron deficiency (replace iron orally; search for occult gastrointestinal blood loss with colonoscopy in adults to rule out colorectal cancer); (2) basophilic stippling on the smear plus ring sideroblasts on marrow plus elevated blood lead level equals lead poisoning (lead inhibits ferrochelatase and ALA dehydratase, causing protoporphyrin accumulation; in children watch for encephalopathy and chronic learning issues; in adults watch for wrist drop and abdominal colic; treat with chelation: succimer in children, EDTA plus dimercaprol if severe); (3) ring sideroblasts on Prussian blue stain of marrow plus high ferritin plus high serum iron plus low TIBC equals sideroblastic anemia (give pyridoxine / B6 for X-linked inherited form; remove offending toxin for acquired form: alcohol, isoniazid, chloramphenicol, lead; treat underlying myelodysplastic syndrome if present).
Try a free question
CoreA menstruating patient has fatigue, pica, koilonychia, microcytosis, low ferritin, high TIBC, high RDW, and low serum iron. Which diagnosis is most likely?
Show answer and explanation
Answer: A. Iron deficiency anemia. Low ferritin with high TIBC and pica points to iron deficiency anemia.
Why the other choices are tempting
- B. Lead poisoning needs exposure clues and basophilic stippling.
- C. Sideroblastic anemia has ring sideroblasts and increased iron stores.
- D. Thalassemia trait has globin-chain defects with often normal iron studies.
- E. Anemia of chronic disease has low TIBC and normal or high ferritin.
Flashcards
Tap a card to flip it.
What iron studies point to iron deficiency?
Low ferritin with high TIBC points to iron deficiency anemia.
What smear clue points to lead poisoning?
Coarse basophilic stippling in the right exposure setting points to lead poisoning.
Quick answers
What is the fastest way to tell Iron deficiency anemia from Lead poisoning and sideroblastic anemia?
Iron deficiency is iron missing; lead and sideroblastic anemia are heme-synthesis problems with iron present or misused.
What is the key clue for Iron deficiency anemia?
Iron deficiency anemia causes microcytosis with low ferritin, high TIBC, high RDW, pica, koilonychia, and chronic blood loss or poor intake.
What is the key clue for Lead poisoning and sideroblastic anemia?
Lead poisoning causes microcytosis, abdominal pain, neurocognitive symptoms, coarse basophilic stippling, and heme enzyme inhibition; sideroblastic anemia causes ring sideroblasts with increased iron.
What is the common trap with Iron deficiency anemia vs Lead poisoning and sideroblastic anemia?
All can be microcytic, so ferritin/TIBC, basophilic stippling, and ring sideroblasts decide the cause.