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Aplastic Anemia by Mind Map: Aplastic Anemia

1. Pathophysiology etiology

1.1. Characteristic Lesion: Hypocellular bone marrow that is replaced with fat

1.2. Pathogenesis is not certain

1.3. Extrinsic immune mediated suppression of bone marrow

1.4. Intrinsic abnormality of stem cells

1.4.1. (IMMUNITY) CYTOTOXIC T CELLS appear to be main culprit

1.5. (IMMUNITY) Primary mechanism: Immune mediated destruction directed against hematopoietic stems cells.

1.6. (IMMUNITY) Reduced number of T reg cells and immune abnormalities: CD4, CD8, Th17

1.7. Stem cell alteration due to exposure to drugs, (INFECTIONS), or other environmental factors.

2. Causative Factors

2.1. Drugs, radiation & toxins

2.1.1. Sulfonamides , anti seizure medications, certain antibiotics, anti-inflammatory meds, immunosuppressive agents.

2.1.2. (INJURY & INFLAMMATION) Ionizing radiation

2.1.3. (INJURY & INFLAMMATION to our cells) Toxins: solvents, degreasing agents, industrial chemicals, insecticides, pesticides, and benzene.

2.1.4. (INFECTION) Viral infection: Hepatitis, HIV

2.1.5. Myelodysplastic syndromes: chromosome abnormality.

2.1.6. Inherited genetic abnormalities

2.2. Acquired clonal abnormalities during lifetime.

3. Risk Factors

3.1. Exposure to chemical agents such as: alkylating agents, antimetabolites, benzene, chloramphenicol, and inorganic arsenicals

3.2. Exposure to physical agents: whole body irradiation and viral infections

3.3. Inherited mutations such as fanconi anemia and telomerase defects

3.4. Exposure to toxins such as solvents, insecticides, pesticides

3.5. TERT TERC mutations : genes in telomere repair pathway as it makes bone marrow vulnerable to environmental insults like drugs and viruses.

4. Diagnostic Tests

4.1. Blood tests and bone marrow biopsy

4.2. Erythrocytes, leukocytes, and platelets are diminished

4.3. Marrow is yellowish white material which is fat, fibrous tissues and lympocytes

5. Common Findings

5.1. Recurrent Infections:Bacterial and fungal

5.2. Mucosal Hemorrhage or Menorrhagia

5.3. Paroxysmal nocturnal hemoglobinuria

5.4. Finger nail dystrophy , skin lesions

5.5. CBC: reveals pancytopenia like neutropenia, thrombocytopenia and anemia with reticulocytopenia

5.6. Hypoxemia, pallor, weakness, fever, dyspnea, hemorrhage

5.7. Ulcerations of mouth, pharynx, or low grade cellulitis of neck.

5.8. Potential paresthesias, splenomegaly, and neurologic changes.

6. Treatments

6.1. Bone Marrow Transplant

6.2. Immunosuppression

6.2.1. Antithymocyte globulin and cyclosporine, corticosteroids (suppresses lymphocytes)

6.3. Radiation, chemotherapy to decrease disease causing lymphocytes.