First Things First
- Inherited hemoglobinopathies caused by disordered Hb synthesis
- Name is based on which chain subunit is underproduced; however, this underproduction leads to overproduction of other subunits.
- So a pt with beta-thalassemia may have excess alpha, delta, gamma subunits
- Anemia is a consequence of ineffective erythropoiesis and hemolysis combined.
- Often the complications of iron overload syndromes prompt the complication leading to ICU admission.
- The overall contribution of these two processes differs in various forms of thalassemia.
- Cooley’s anemia is a severe form of beta-thalassemia that may be seen in ICU care.
- Globin reduction contributes to diminished hemoglobin molecules (hypochromasia) and small structure (microcytosis).
- Development of unchecked accumulation of subunits causes unstable molecules, leading to apoptosis and hemolysis and poor iron acclimation.
- Anemia causes excess erythropoietin, but this is counteracted by ineffective production.
- Accelerated apoptosis is major factor in dysfunctional erythropoiesis, caused by excess chain deposition in erythroid progeny.
- Beta-thalassemia is common in Mediterranean countries, North Africa, Middle East, India, and Europe.
- Alpha-thalassemia: usually of Asian origin but also seen in India, the Middle East, and Africa; pts with severe types rarely survive (hydrops fetalis)
- Both types can co-exist, usually lessening the severity of disease.
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