鐵粒幼紅細胞性貧血(sideroblastic anaemia)的資料

Sideroblastic anaemias are a heterogeneous group of refractory anaemias. They are characterized by the presence of abnormal ringed sideroblasts in bone marrow aspirate. The sideroblasts form due to reduced haemoglobin synthesis, resulting in the accumulation of iron within red blood cell precursors. Cases can, rarely, be congenital but are more usually acquired and sometimes represent a stage in the development of myelodysplastic syndromes.

Epidemiology Hereditary forms of sideroblastic anaemia are X-linked and more common in males. Cases can be related to ataxia and the condition may not present until the fourth decade or later if mild 1. In addition to the myelodysplastic syndromes, sideroblastic anaemia can also occur in other bone marrow diseases including myeloma, polycythaemia rubra vera, myelosclerosis and leukaemias

Secondary causes include:

Inflammatory conditions (e.g. rheumatoid arthritis)
Systemic lupus erythematosus
Chronic infections
Drug toxicity - e.g. chloramphenicol, cycloserine, isoniazid, linezolid, pyrazinamide
Chronic Alcoholism
Haemolytic Anaemia
Malabsorption Syndromes
Myxoedema
Lead Poisoning
Pregnancy
Presentation Clinical features are those related to anaemia in general. There are no specific signs or symptoms related to sideroblastic anaemia alone.

Investigations An FBC usually shows a moderate anaemia. The MCV is normal or increased but can be low. High serum iron and transferring saturation also occur. The blood film shows a dimorphic population of both normal and hypochromic red blood cells. Diagnosis is made from bone marrow examination demonstrating the presence of ring sideroblasts with a generalized increase in iron stores.

Management
Non-Drug Treatment is mainly supportive. Red cell transfusion is given for symptomatic anaemia. Iron chelation with desferrioxamine should be considered after 20-25 units of red cells have been received.2 Avoid alcohol and vitamin C as these increase iron absorption

Drugs The use of erythropoietin +/- granulocyte colony-stimulating factor has been demonstrated to reduce the need for red cell transfusion in some patients with myelodysplastic syndrome but the studies were small.2 Patients with hereditary sideroblastic anaemia may respond to pyridoxine.2,3 Allogenic peripheral stem cell transplantation has been used with success in pyridoxine refractory hereditary sideroblastic anaemia.4

References Used

Furuyama K, Harigae H, Kinoshita C, et al; Late-onset X-linked sideroblastic anemia following hemodialysis.;Blood 2003 Jun 1;101(11):4623-4. Epub 2003 Jan 16.[abstract]
Bowen D, Culligan D, Jowitt S, et al; Guidelines for the diagnosis and therapy of adult myelodysplastic syndromes.;Br J Haematol 2003 Jan;120(2):187-200.
Cazzola M, May A, Bergamaschi G, et al; Familial-skewed X-chromosome inactivation as a predisposing factor for late-onset X-linked sideroblastic anemia in carrier females.;Blood 2000 Dec 15;96(13):4363-5.[abstract]
Gonzalez MI, Caballero D, Vazquez L, et al; Allogeneic peripheral stem cell transplantation in a case of hereditary sideroblastic anaemia.;Br J Haematol 2000 Jun;109(3):658-60.[abstract]
British Journal of Haematology 2003; 120: 187-200 Guidelines for the diagnosis and therapy of adult myelodysplastic syndromes.
Acknowledgements EMIS is grateful to Dr Lisa Scobbie for authoring this article. The final copy has passed peer review of the independent Mentor GP authoring team. ©EMIS 2005.

Porphyria

(Redirected from Congenital sideroblastic anaemia)



For the poem by Robert Browning see Porphyria's Lover. For the fictional Vampiric disease, see Porphyric Hemophilia (Elder Scrolls).
The porphyrias are inherited or acquired disorders of certain enzymes in the heme biosynthetic pathway (also called porphyrin pathway). They are broadly classified as hepatic porphyrias or erythropoietic porphyrias, based on the site of the overproduction and mainly accumulation of the porphyrins (or their chemical precursors). They manifest with either skin problems or with neurological complications (or occasionally both).
The term derives from the Greek πορΦυρα (porfura), meaning "purple". The name is likely to have been a reference to the purple discoloration of some body fluids in patients during an attack.[1] Although original descriptions are attributed to Hippocrates, the disease was first explained biochemically by Felix Hoppe-Seyler in 1874,[2] and acute porphyrias were described by the Dutch physician B.J. Stokvis in 1889.[3][1]
http://en.wikipedia.org/wiki/Congenital_sideroblastic_anaemia