Aplastic Anemia

First Things First (assess & treat for the following)

• Genetic or acquired marrow disorder with reduction in all marrow cellular elements
  
  • Technically, a pancytopenia
  • ParvoB19 virus only causes erythrogenic aplasia
• Marked reduction in CD34 cells responsible for committed progeny and stem cells
• Qualitative and quantitative dysfunction of the hematopoietic progenitors unresponsive to hematopoietic growth factors
• Fatty infiltration in marrow
• Not a disease of stromal elements of marrow
• Acquired cases are felt to be autoimmune from T-cell destruction of all primitive cell lines, much like other autoimmune disorders.
• There is a close relationship of aplastic anemia with AML and myelodysplasias.
• Common etiologies include:
  
  • Toxicity from medications (chloramphenicol, antineoplastic drugs)
  • Chemicals (benzene, organophosphates, chlorinated hydrocarbons)
  • Viral infections (EBV in 4-6 wks; HIV, HHV-6 and their related drugs, parvoB19 virus)
  • Pregnancy, post-liver transplant, GVHD post-transfusion
  • Radiation-induced
  • Congenital disorders are usually associated with childhood syndromes such as Fanconi’s anemia, Pearson’s syndrome, Diamond-Blackfan syndrome, familial aplastic anemia.
  • Acquired disorders predominate over congenital causes.
• Eosinophilic fasciitis: autoimmune, connective tissue disorder with aplastic anemia and painful swelling, induration of skin/subcutaneous fascia
  
  • Minimal response to therapy, antibody-mediated, rare disorder