Aplastic Anemia

1. Causative Factors

1.1. autoimmune

1.2. autoimmune

1.3. idiopathic

1.4. environmental exposure to drugs, toxins, viruses

2. Diagnostic Tests

2.1. complete blood count

2.2. leukocyte differential

2.3. reticulocyte count

2.4. positive diagnosis only made with bone marrow aspiration and biopsy showing hypocellularity ( erythrocytes, leukocytes, platelets <30%of the bone marrow)

3. Treatment

3.1. 3 effective treatments:

3.2. 1. allogeneic bone-marrow transplantation

3.3. 2. immunosuppressive therapy with horse antithymocyte globulin and ciclosporin;

3.4. 3. high-dose cyclophosphamide without transplantation of bone marrow

4. Symptoms

4.1. may appear suddenly or insidiously over weeks, months

4.2. dyspnea on exertion

4.3. fatigue

4.4. easy bruising

4.5. peticchiae

4.6. epistaxis

4.7. gingival bleeding

4.8. heavy menses

4.9. headache

4.10. fever

5. Etiology

5.1. most cases are autoimmune

5.2. auto-reactive lymphocytes mediate the destruction of hemopoietic stem cells

5.3. bone marrow is "empty" of blood cells = aplastic

5.4. pancytopenia = absence of all 3 blood cell types: erythrocytes, leukocytes, platelets

5.5. fat, fibrous tissue , lymphocytes replace blood cells in bone marrow = hypocellularity

6. Risk Factors

6.1. high-dose radiation or chemotherapy

6.2. certain prescription drugs: chloramphenicol, gold compounds used to treat rheumatoid arthritis

6.3. exposure to toxic chemicals

6.4. some blood diseases, autoimmune disorders and serious infections

6.5. in rare cases, pregnancy

7. Common Findings

7.1. incidence: 2-5 new cases per million per year

7.2. pancytopenia left untreated = death within 1 year

7.3. acquired aplastic anemia usually strikes two age groups: 15-25 years, & 60 years & over