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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Last updated: May 5, 2010