sideroblastic anemia
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Introduction
A group of disorders characterized by ringed sideroblasts in nucleated erythroid precursors in the marrow.
Etiology
- hereditary
- rare, sex-linked hereditary defect of gamma-aminolevulinic acid synthase
- acquired:
- refractory anemia with ringed sideroblasts
- heavy alcohol ingestion
- pharmaceutical agents
- nutritional/toxins
- excess zinc intake
- copper deficiency
- lead poisoning
Pathology
- >10% of normoblasts contain iron-laden mitochondria that surround the nucleus & appear as pathognomonic rings when stained with Prussian blue
- the final step in heme synthesis (insertion of iron) occurs in the mitochondria
- iron overload in hereditary form may be severe
Laboratory
- complete blood count
- peripheral smear
- hypochromic, microcytic anemia
- often shows dimorphic population of erythrocytes
- macrocytic erythrocytes with basophilic stippling that stain positive for iron[2]*
- serum iron levels are elevated
- % transferrin saturation is generally high (30-80%)
- serum ferritin levels are generally elevated (50-300 ug/L)
- bone marrow biopsy
* MKSAP17 classifies sideroblastic anemia as macrocytic anemia
Management
- pyridoxine 100-200 mg PO QD
- hereditary forms often respond
- acquired forms less frequently respond
- stop offending agents
More general terms
More specific terms
- acquired idiopathic sideroblastic anemia
- refractory anemia with ringed sideroblasts (RARS)
- sideroblastic anemia with spinocerebellar ataxia
- X-linked sideroblastic anemia
Additional terms
References
- ↑ Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 1725
- ↑ Jump up to: 2.0 2.1 Medical Knowledge Self Assessment Program (MKSAP) 11, 16, 17. American College of Physicians, Philadelphia 1998, 2012, 2015
- ↑ Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 643, 2157