Sideroblastic anemia 2675115 216474173 2008-06-01T20:41:19Z 35.9.78.29 /* Diagnosis */ {{Infobox_Disease | Name = {{PAGENAME}} | Image = | Caption = | DiseasesDB = 12110 | ICD10 = {{ICD10|D|64|0|d|60}}-{{ICD10|D|64|3|d|60}} | ICD9 = {{ICD9|285.0}} | ICDO = | OMIM = | MedlinePlus = | eMedicineSubj = | eMedicineTopic = | MeshID = D000756 | }} '''Sideroblastic anemia''' is caused by the abnormal production of [[red blood cell]]s, usually as part of [[myelodysplastic syndrome]],<ref name="titleSideroblastic Anemias: Anemias Caused by Deficient Erythropoiesis: Merck Manual Professional">{{cite web |url=http://www.merck.com/mmpe/sec11/ch130/ch130c.html |title=Sideroblastic Anemias: Anemias Caused by Deficient Erythropoiesis: Merck Manual Professional |accessdate=2008-03-23 |format= |work=}}</ref> which can evolve into [[hematological malignancy|hematological malignancies]] (especially [[acute myelogenous leukemia]]). Thus, the body has iron available, but cannot incorporate it into hemoglobin. "Sideroachrestic anemia" is sometimes used as a synonym for sideroblastic anemia.<ref>{{Dorlands|a_37|12132489}}</ref> ==Classification== Sideroblastic anemia is typically divided into subtypes based on its cause. * Hereditary sideroblastic anemia may be X-linked<ref>{{cite web |url=http://ghr.nlm.nih.gov/condition=xlinkedsideroblasticanemia |title=X-linked sideroblastic anemia - Genetics Home Reference |accessdate=2008-03-23 |format= |work=}}</ref> or autosomal. * Acquired, or secondary, sideroblastic anemia develops after birth and is divided according to its cause. ==Causes== The common feature of these causes is a failure to completely form [[heme]] molecules, whose biosynthesis takes place partly in the [[mitochondrion]]. This leads to deposits of iron in the [[mitochondria]] that form a ring around the [[Cell nucleus|nucleus]] of the developing [[red blood cell]]. Sometimes the disorder represents a stage in evolution of a generalized bone marrow disorder that may ultimately terminate in acute leukemia. * Toxins: [[lead]] or [[zinc]] poisoning * Drug-induced: [[ethanol]], [[isoniazid]], [[chloramphenicol]], [[cycloserine]] * Nutritional: [[pyridoxine]] or [[copper]] deficiency * Genetic: ALA synthase deficiency ([[X-linked]]) ==Diagnosis== Ringed sideroblasts are seen in the bone marrow. The anemia is moderate to severe and dimorphic with marked [[anisocytosis]] and [[poikilocytosis]]. Basophilic stippling is marked and target cells are common. [[Pappenheimer bodies]] are present. The [[Mean corpuscular volume|MCV]] is decreased (ie. a [[microcytic anemia]]). The [[Red blood cell distribution width|RDW]] is increased with the [[red blood cell]] histogram shifted to the left. [[Leukocyte]]s and [[platelet]]s are normal. Bone marrow shows erythroid hyperplasia with a maturation arrest. In excess of 40% of the developing erythrocytes are ringed sideroblasts. Serum iron, percentage saturation and [[ferritin]] are increased. The [[Total iron-binding capacity|TIBC]] is normal to decreased. Stainable marrow hemosiderin is increased. ==Laboratory findings== * Increased [[ferritin]] levels * Decreased [[total iron-binding capacity]] * [[Hematocrit]] of about 20-30% * Serum Iron: High * High [[transferrin saturation]] * The [[mean corpuscular volume]] or MCV is usually normal or slightly increased; although it may occasionally be low, leading to confusion with iron deficiency.{{ref|Laboratory_findings}} * With [[lead poisoning]], see coarse basophilic stippling of red blood cells on peripheral blood smear * Specific test: Prussian Blue stain of RBC in marrow. Shows ringed sideroblasts. ==Treatment== Occasionally, the anemia is so severe that support with transfusion is required. These patients usually do not respond to [[erythropoietin]] therapy.<ref>"Sideroblastic Anemia" Tierney/McPhee/Papadakis Current Medical Diagnosis and Treatment. 45th Ed. McGraw-Hill. ISBN: 0-07-145410-1.</ref> Some cases have been reported that the anemia is reversed or heme level is improved through use of moderate to high doses of pyrodoxine (Vitamin B6.) In severe cases of SBA, bone marrow transplant is also an option with limited information about the success rate. Some cases are listed on MedLine and various other medical sites. In the case of [[isoniazid]]-induced sideroblastic anemia, the addition of B6 is sufficient to correct the anemia. ==See also== * [[Anemia]] * [[Siderosis]] == References == {{reflist}} == External links == * [http://sickle.bwh.harvard.edu/sideroblastic.html Sideroblastic Anemias: Introduction - Information Center for Sickle Cell and Thalassemic Disorders ] *[http://www.irondisorders.org/Disorders/Sideroblastic.asp A concise description of this group of diseases from the Iron Disorders Institute] {{Hematology}} [[Category:Diseases]] [[Category:Genetic disorders]] {{disease-stub}} {{genetic-disorder-stub}} [[it:Anemia sideroblastica]] [[ja:鉄芽球性貧血]] [[pl:Niedokrwistość syderoblastyczna]] [[pt:Anemia sideroblástica]]