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Abstract
The β-Thalassemia is an inherited hemoglobin disorder caused by impaired synthesis of the β-globin chain and resulting in chronic hemolytic anemia.
Thomas Cooley and Pearl Lee described a form of severe anemia, occurring in children of Italian origin and associated with splenomegaly and characteristic bone changes. Because all early cases were reported in children of Mediterranean origin, the disease was later termed thalassemia, from the Greek word for sea, thalassa .
The b-thalassemias include four clinical syndromes of increasing severity: two conditions are generally asymptomatic, the silent carrier state and b-thalassemia trait, and usually result from the inheritance of one mutant b globin gene, and two require medical management, thalassemia intermedia and thalassemia major.
Patients referred to as having thalassemia major are usually those who come to medical attention in the first year of life and subsequently require regular transfusions to survive. Those who present later or who seldom need transfusions are said to have thalassemia intermedia .
Complications of thalassemia can be grouped as (1) transfusion-transmitted infections, (2) transfusional iron overload, (3) toxicities of iron chelation therapy, and (4) bacterial infections
Transfusional iron deposits in multiple tissue sites, including the liver and heart. The resultant hemochromatosis prompts cardiac dysfunction, which remains the leading cause of death in thalassemia, despite advances in treatment .
Cardiac disorders and, most notably, left-sided heart failure are considered the most common causes of death in patients with ß-thalassemia major.Recently reported that apart from iron overload, myocarditis is another contributing factor in the pathogenesis of heart failure. Myocarditis can cause acute or chronic left ventricular systolic dysfunction and dilatation, which appear to be mediated by predominantly immunologic mechanisms rather than viral infection and replication.
Although TM and TI share common basic pathophysiological mechanisms, cardiac involvement may be different in the latter because these patients live longer and generally have low hemoglobin levels and lower iron loads.
Strategies for thalassemia control consist of offering the best treatment to patients and prevention of the birth of new cases. Treatment with hypertransfusion and iron chelation can prevent pathology and improve the quality of life in many patients and is associated with prolonged life expectancy.
Bone marrow transplantation is the only means of curing thalassemia at present and can be considered if a sibling is found to be an HLA-matched donor.
Hydroxyurea can stimulate red cell Hb F production resulting in prolonged life-span and better function in oxygen delivery.
The ultimate objectives of thalassemia prevention are to screen for carriers, to offer prenatal diagnosis of the high risk fetus, and to provide choices for abortion for the couples to consider. Identification of couples at risk is at present performed by pregnancy screening.