Skip to Main Content

++

DEFINITION

++

  • Aplastic anemia is marked by pancytopenia with markedly hypocellular marrow and normal marrow cell cytogenetics.

  • Incidence worldwide is two to five cases/million population per year and five to twelve cases/million population per year in the United States (and in other industrialized countries). Incidence is approximately twice as high in Asian countries.

  • Peak incidence is between ages 15 and 25 and 65 and 69 years.

  • The definitions for spectrum of severity of aplastic anemia are shown in Table 3–1.

++
Table Graphic Jump Location
TABLE 3–1DEGREE OF SEVERITY OF ACQUIRED APLASTIC ANEMIA*
++

ETIOLOGY AND PATHOGENESIS

++

Pathogenesis

++

  • Immune suppression of marrow by autoreactive T lymphocytes

  • Toxic injury to stem and/or progenitor cells (eg, certain chemotherapy or drugs) (see Table 3–2)

  • Inherited intrinsic stem cell defect (eg, Fanconi anemia)

++
Table Graphic Jump Location
TABLE 3–2SOME DRUGS ASSOCIATED WITH MODERATE RISK OF APLASTIC ANEMIA*
++

Acquired

++

  • Acquired T lymphocyte–mediated autoimmune suppression of hematopoietic stem cells and/or progenitor cells in most cases (~70%) (see Table 3–3)

  • Paroxysmal nocturnal hemoglobinuria (PNH) (may be manifest by cytopenias and hypoplastic marrow)

  • Chemicals (eg, high-dose benzene exposure); rare today in countries with workplace and product regulations ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.