Synopsis
Recognise defective mitochondrial haem synthesis, distinguish inherited, clonal and reversible acquired causes, interpret ring sideroblasts correctly, and treat the driver while preventing transfusional iron injury.
- Sideroblastic anaemia describes ineffective erythropoiesis in which iron accumulates within mitochondria encircling erythroblast nuclei as ring sideroblasts on marrow iron staining.
- It is a morphological mechanism rather than one disease: causes include inherited ALAS2-related disease, myelodysplastic neoplasms, alcohol, medicines, copper deficiency and lead toxicity.
- The mean cell volume may be low, normal or high; a dimorphic film and raised ferritin or transferrin saturation can suggest iron-loaded ineffective erythropoiesis.
Key red flags
New severe cytopenias, circulating blasts, infection or bleeding needs urgent myeloid-neoplasm assessment rather than routine nutritional follow-up.
Investigation priorities
Define cell size, dimorphism and other cytopenias.
Management branches
Persistent anaemia has atypical indices, dimorphism or unexpectedly high iron stores.
- Review count trajectory, reticulocytes, film and iron measures and stop reflex iron prescribing until true deficiency is demonstrated.
- Take a detailed alcohol, medicine, zinc, surgery, occupation and family history, then test copper and lead where exposure makes them plausible.
Key medicines
PyridoxineA haematologist may supervise an oral therapeutic trial, commonly 50–200 mg daily depending on suspected mechanism, with a defined blood-response review and lowest effective maintenance dose.
Copper replacementUse an oral or intravenous elemental-copper regimen selected by severity and absorption, with specialist monitoring of copper, zinc, counts and neurological response.