β-thalassemia intermedia: a clinical perspective

Abstract

Our understanding of the molecular and pathophysiological mechanisms underlying the disease process in patients with β-thalassemia intermedia has substantially increased over the past decade. Earlier studies observed that patients with β-thalassemia intermedia experience a clinical-complications profile that is different from that in patients with β-thalassemia major. In this article, a variety of clinical morbidities are explored, and their associations with the underlying disease pathophysiology and risk factors are examined. These involve several organs and organ systems including the vasculature, heart, liver, endocrine glands, bone, and the extramedullary hematopoietic system. The effects of some therapeutic interventions on the development of clinical complications are also discussed.

Figure 1.

Main genetic profiles that could lead to the β-thalassemia intermedia phenotype. Hb, hemoglobin; HPFH, hereditary persistence of fetal hemoglobin.

Figure 2.

Factors contributing to the hypercoagulable state in β-thalassemia intermedia. RBC, red blood cells. (From Cappellini et al. 2010; reprinted, with permission.)

Figure 3.

Paraspinal extramedullary hematopoietic pseudotumors. (A) Chest X-ray showing expanded anterior rib ends consistent with medullary hyperplasia. A paraspinal mass is seen in the right lower zone (white arrow). (B) Computed tomography scan showing inactive paraspinal extramedullary hematopoietic lesion with increased density compared with soft tissue, caused by iron deposition (black arrowheads). (C) Magnetic resonance image of cervical and thoracic spine. T2-weighted sagittal image showing thoracic cord compression by extramedullary intraspinal epidural hematopoietic mass from T2 to T10 (white arrows). (From Haidar et al. 2010; reprinted, with permission.)