Related Subjects:
| Sideroblastic Anaemia
| Splenectomy
π About
- Sideroblastic anaemia is a rare form of anaemia characterised by ineffective erythropoiesis and the presence of ring sideroblasts in the bone marrow.
- Sideroblasts are erythroblasts (immature RBCs) with iron-loaded mitochondria encircling the nucleus (seen with Prussian Blue stain).
- Iron is available but cannot be incorporated into haem β leading to anaemia + systemic iron overload.
βοΈ Pathophysiology / Aetiology
- Final step in haem synthesis (ferrochelatase inserts Fe2+ into protoporphyrin IX) is impaired.
- Alcohol: interferes with pyridoxal-5β-phosphate (B6), a cofactor for ALAS (aminolevulinic acid synthase).
- Lead: inhibits ferrochelatase and ALA dehydratase.
- Hereditary forms: ALAS2 mutation (X-linked), ferrochelatase deficiency.
- Iron overload results from ineffective erythropoiesis, sometimes leading to hepatosplenomegaly.
π©Ί Clinical Presentation
- Fatigue, weakness, pallor.
- Flow murmurs (high-output state due to anaemia).
- Hepatosplenomegaly from iron deposition.
- History: alcohol, drugs (isoniazid, pyrazinamide), family history.
π§ͺ Causes of Sideroblastic Anaemia
Cause | Mechanism | Examples |
Acquired β Toxins | Disrupt haem synthesis | Alcohol, Lead |
Acquired β Drugs | Block B6 metabolism | Isoniazid, Pyrazinamide |
Myelodysplastic syndromes (MDS) | Ineffective erythropoiesis | Refractory anaemia with ring sideroblasts (RARS) |
Hereditary | Genetic enzyme defects | ALAS2 mutation, ferrochelatase deficiency |
π Investigations
- Blood film: dimorphic picture (mix of microcytic & normocytic cells).
- Hypochromic microcytic anaemia common.
- Bone marrow biopsy: ring sideroblasts with perinuclear iron granules (Prussian Blue).
- Iron studies: β serum iron, β ferritin, β transferrin saturation.
- Consider LFTs and genetic testing if hereditary suspected.
βοΈ Management
- Address underlying cause: stop alcohol, remove toxins/drugs.
- Pyridoxine (B6) trial: particularly in hereditary/ALAS2-related cases.
- Supportive: blood transfusions (but β iron overload risk).
- Iron overload: consider iron chelation (e.g., deferoxamine).
- In severe/refractory cases: erythropoietin (EPO) or haematopoietic stem cell transplantation.
π References
- BNF β Anaemia management
- NICE CKS β Anaemia (non-iron deficiency)
- Hoffbrandβs Essential Haematology