Aplastic Anemia - Overview



Who?

• M = F

• 3 peaks:	1) Childhood	2) 15-25 years	3) >60 years



What?

• Aplastic anemia = Hypocellular bone marrow + pancytopenia



Mechanisms:

• Direct Damage to Marrow (Toxic injury to BM)

• Constitutional Syndromes (specific loss-of-function germline mutations)

• Immune Aplastic Anemia



Clinical Presentation:

• Fever

• Fatigue

• Lightheadedness

• Dizziness

• Irritability

• Headaches

• Pale skin color

• Difficulty breathing

• Neutropenia - recurrent infections/fevers

• Thrombocytopenia - ecchymoses, mucosal bleeding, and petechiae



Causes:

• Constitutional Syndromes:

  - Genetic lesions that diminish the capacity for hematopoietic stem cells to repair DNA, as in Fanconi anemia, GATA2 deficiency, CTLA4 deficiency, Dyskeratosis congenita

• Drugs:

  - Cytotoxic drugs/Chemotherapy

  - Antithyroid medications (methimazole and propylthiouracil)

  - β-lactam antibiotics

  - Sulfonamides

  - NSAIDs

  - Anticonvulsants

  - Gold salts

• Chemical Agents:

  - Benzene

• Physical Agents:

  - Radiation

• Idiopathic

• Infections:

  - Parvovirus B19

  - EBV

  - CMV

  - HCV

  - HIV

• Immune Aplastic Anemia:

  - Hepatitis, eosinophilic fasciitis, and thymoma



DDX:

• Inherited marrow-failure syndromes

• Paroxysmal nocturnal hemoglobinuria

• Hypocellular myelodysplastic syndrome (MDS) (normal or increased number of CD34+ cells)

• Human immunodeficiency virus (HIV)

• Parvovirus B19

• Mycobacteria

• Cytomegalovirus (CMV)

• Epstein-Barr virus (EBV)

• Leukemia



Hypocellular/Hypoplastic MDS:

• ↓ bone marrow cellularity + dysplastic cells + cytogenetic abnormalities typical for MDS

• Suggested by bone marrow with dysplastic megakaryocytes and a normal or increased number of CD34+ cells (not consistent with aplastic anemia)



Labs:

• Peripheral Pancytopenia:

	• ↓ RBC

	• ↓ WBC

	• ↓ PLT

• Reticulocyte index < 2

• EPO Level ↑

• Marrow hypoplasia/fatty bone marrow

• Number of CD34+ cells is much reduced in aplastic anemia



Treatment:

• Improve the symptoms that may result from low blood counts

• Allogeneic HSCT for younger than 50 years who have a suitable match

• Immunosuppression - cyclosporine and antithymocyte globulin



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