Snapshot A 69-year-old man is brought to the emergency department by police after being found stumbling in the middle of the street at night. He smells strongly of whiskey and is found to have a blood alcohol content level of 0.23%. Laboratory studies are ordered, and the patient is found to have a hemoglobin of 7 g/dL and a hematocrit of 21%. Iron studies show an increase in free iron levels. A peripheral blood smear is obtained and shows the finding seen in the image. Introduction Overview sideroblastic anemias are a group of inherited and acquired anemias in which iron accumulates in the mitochondria of erythrocyte precursors ringed sideroblasts (iron-laden erythrocytes with Prussian-blue stained mitochondria) seen on bone marrow aspirate Genetics inheritance pattern X-linked (inherited sideroblastic anemia) mutations ALAS2 gene login to view 1 more bullet Epidemiology Incidence rare Demographics X-linked recessive type of inherited sideroblastic anemia occurs more commonly in males median age of occurence of primary acquired sideroblastic anemia is 74 years Risk factors alcoholism vitamin B6 deficiency lead poisoning copper deficiency ETIOLOGY Pathophysiology mitochondrial pathways in erythrocyte precursors are disrupted, leading to accumulation of iron in the mitochondria excessive iron deposits in erythroblasts form a ring around the nucleus, making a ringed sideroblast heme synthesis is impaired, leading to ↓ heme production and abnormal RBCs X-linked sideroblastic anemia login to view 2 more bullets isoniazid login to view 1 more bullet chronic alcohol use login to view 2 more bullets lead poisoning login to view 3 more bullets Presentation Symptoms general symptoms of anemia fatigue weakness dyspnea on exertion lack of coordination (cerebellar symptoms) diarrhea Physical exam growth delay in children ataxia ↓ deep-tendon reflexes incoordination dyspnea muscular weakness Studies Serum labs ↑ serum iron and ferritin ↓ TIBC ↓ or normal MCV Histology peripheral blood smear hypochromic RBCs Pappenheimer bodies in RBCs login to view 1 more bullet low reticulocyte count bone marrow stained with Prussian blue ringed sideroblasts login to view 1 more bullet Differential Iron deficiency anemia key distinguishing factor ↓ serum iron and ferritin Megaloblastic anemia key distinguishing factor megaloblastic changes seen on peripheral blood smear and bone marrow rather than ringed sideroblasts Treatment Medical pyridoxine (vitamin B6) supplementation Prognosis Highly variable depending on cause anemia due to reversible causes (i.e., alcohol, drugs) do not have long-term sequelae Secondary hemochromatosis (from transfusions) and leukemia are major causes of death