Aplastic Anemia
Morphologic, Etiologic Possible causes: Investigations and treatmentDefinition : Pancytopenia with hypocellularity (Aplasia) of Bone Marrow
EtiologyInheritedFanconi’s Anemia
Acquired
1- primary idiopathic aplastic anemia 2- Secondary aplastic anemiaThe primary aplastic anemia
** 50 % of cases ** No explanation ** Thought to be an autoimmune condition in which there are cytotoxic T- lymphocytes which destroy the stem cellSecondary aplastic anemia
Causes : 1- Drugs * Dose related : Alkylating agent Antibiotics : Chloramphenicol Idiosyncratic : Chloramp , gold , NSAID , anticonvulsant , penicillamin2- Toxins : benzene , insecticides . 3- Viral infection : hepatitis , EPV ,HIV 4- PNH 5- Pregnancy 6- Radiation. 7- Immune disease : Hypogammaglobulinemia Graft-versus host disease in immunodeficiency .
Pathogenesis
Immune mechanism responsible for most of the cases of Idiopathic acquired aplastic anemiaActivated Cytotoxic T cells in Blood & Bone marrow Bone marrow failureClinical Features
Signs & symptoms of :Anemia:……….Bleeding: Ecchymoses ,Bleeding gums, EpistaxisInfections: Fever,Mouth ulcersLymphadenopathy and splenomegaly are highly atypical of aplastic anemia .
DiagnosisBlood peripheral smear : Pancytopenia and reticulocytopenia Bone marrow aspiration & biopsy : Hypocellular / aplastic bone marrow with increased fat spaces Tests for underlying cause ( viral titers)
Other causes of Pancytopenia: Myelofibrosis Megaloblastic anemia Bone Marrow infiltration or Replacement: Lymphoma, Myeloma,Acute Leukemia, Secondaries Hyperspleenisn SLE Disseminated TB PNH Sepsis
BM Aspiration
BM BiopsyBM biopsy hypocellular ,increased fat spaces
TreatmentTreatment of underlying cause –if possibleRemoval of causeSupportive care Blood & platelet transfusion Infection : Broad spectrum antibioticssepsisBone Marrow Transplant (SCT) patient age <40yrs , availability of a HLA-identical sibling marrow donor
Immunosuppression: Cyclosporine, Glucocorticoids : in congenital Pure Red Cell Aplasia Antilymphocyte or Antithymocyte globulin (ALG / ATG) Cyclophosphomide Androgens Thymectomy : for Adult Pure Red Cell Aplasia