Pathophysiology of Beta-Thalassaemia: (Part – 2) [Chronic Anaemia/Hypoxia]

The basic clinical symptom of β thalassaemia is chronic anaemia-reduced number of RBCs and their haemoglobin (Hb) content, resulting from deficiency in Hb production and haemolysis. Ineffective erythropoiesis, chronic anaemia/hypoxia, and iron overload contribute to the clinical complications of beta thalassaemia through stepwise patho-physiological mechanisms. Ineffective erythropoiesis and peripheral haemolysis (as described in the review part 1) lead to severe anaemia, tissue hypoxia, and a reactive production of erythropoietin (EPO) with a consequent compensatory increase of the number of bone marrow erythroblasts and extramedullary haematopoiesis with characteristic hepatosplenomegaly. In beta thalassaemias, the thalassaemic haemoglobins influence its affinity for oxygen. Because of the hereditary defective haemoglobin molecule, anaemia due to chronic haemolysis is the hallmark of severe haemoglobinopathies resulting in a reduced oxygen carrying capacity and a rightward shift of the dissociation curve i