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Aplastic Anemia

Aplastic Anemia . Aplastic Anemia . Definition: Pancytopenia with hypocellularity (Aplasia) of Bone Marrow One cell line may be affected more than the others Aplastic anemia is a severe, life threatening syndrome in which production of erythrocytes, WBCs, and platlets has failed.

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Aplastic Anemia

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  1. Aplastic Anemia

  2. Aplastic Anemia • Definition: • Pancytopenia with hypocellularity (Aplasia) of Bone Marrow • One cell line may be affected more than the others • Aplastic anemia is a severe, life threatening syndrome in which production of erythrocytes, WBCs, and platlets has failed.

  3. Aplastic anemia may occur in all age groups and both genders. • The disease is characterized by peripheral pancytopenia and accompanied by a hypocellular bone marrow. • Failure of the bone marrow percursors to produce mature cells. Characterized by hypocellular marrow and pancytopenia.

  4. Etiology • Acquired: More common • Inherited: Fanconi anemia Acquired: • Drugs • • Agents with predictable, dose-related effects (e.g., chemotherapeutic drugs) • • Agents with unpredictable, non-dose-related effects (e.g., chloramphenicol) - Cytotoxic drugs - Antibiotics - Chloramphenicol - Anti-inflammatory - Anti-convulsant - Sulphonamides - 2-3 months usually between exposure and the development of aplastic anemia.

  5. Aplastic Anemia: (Cont.) Acquired: • Radiations • Chemicals e.g., Benzene and pesticides • Viruses: • Hepatitis A, Non-A and Non-B • Herpes simplex • E-B virus • Parvovirus: Transient • Important clinically in patients with hemolytic anemias • 5-10% of cases of AA in the West and 10-20% in the Far East. • 2-3 months between exposure to the virus and the development of AA. • Immune: SLE, RA (rheumatoid arthritis) • Pregnancy • Idiopathic: 75% • PNH

  6. INHERITED(20%) • FanconiAnaemia • Dyskeratosiscongenita • Shwachman-Diamond syndrome • Diamond-Blackfan anaemia.

  7. substantial reduction in the number of haemopoietic pluripotential stem cells, and a fault in the remaining stem cells or an immune reaction againstthem, which makes them unable to divide and differentiate sufficiently to populate the bone marrow. • A primary fault in the marrow microenviromnent has also been suggested but the success of stem cell transplantation (SCT) shows this can only be a rare cause because normal donor stem cells are usually able to thrive in the recipient's marrow cavity.

  8. Pathogenesis Potential mechanisms: • Absent or defective stem cells (stem cell failure). • Abnormal marrow micro-environment. • Inhibition by an abnormal clone of hemopoietic cells. • Abnormal regulatory cells or factors. • Immune mediated suppression of hematopoiesis. It is believed that genetic factors play a role. There is a higher incidence with HLA (11) histo comp. Antigen. Immune mechanism is involved.

  9. Pathogenesis (Cont…) The latest theory is: there is an intrinsic derangement of hemopoietic proliferative capacity, which is consistent with life. The immune mechanism attempt to destroy the abnormal cells (self cure) and the clinical course and complications depend on the balance. If the immune mechanism is strong, there will be severe pancytopenia. If not, there will be myelodysplasia.

  10. Forms of disease: • Inevitable: dose related e.g. cytotoxic drugs, ionizing radiation. The timing, duration of aplasia and recovery depend on the dose. Recovery is usual except with whole body irradiation. • Idiosyncratic: unpredictable to drugs e.g., anti-inflammatory antibiotics, anti-epileptic, these agents usually do not produce marrow failure in the majority of persons exposed to these agents.

  11. Clinical Features • Non-specific: • Bruising, petechiae • Manifestations of anemia • Infections • Hematological findings: Peripheral blood: • Pancytopenia: initially only 1 or 2 parameters. WBC < 2.0, Hb < 10. Plat. < 100. No gross morphological abnormalities. • Anemia is usually NCNC. • Reticulocytopenia. • 10% Ham’s test is + (complement mediated lysis)

  12. Clinical Features • Hematological findings: (Cont…) Bone Marrow: • Hypocellular: <50% of normal cellularity Trephine biopsy is the most important for diagnosis. • Most of the cells present are lymphocytes, plasma cells and stromal cells. • Iron stores: increased

  13. BM Aspiration BM Biopsy

  14. BM biopsyhypocellular ,increased fat spaces

  15. Treatment • Withdrawal of etiological agents. • Supportive. • Restoration of marrow activity: • Bone marrow transplant • Immunosuppressive treatment - Prednisolone - Antilymphocyte glob. - Cyclosporin - Anti T cells abs. - Splenectomy • Androgens • Growth factors

  16. Clinical Course • Usually fatal in constitutional type. In the acquired type depends on severity: defined by retic count, months or years depending on the severity. • Stable course: constant over a long period. • Progressive, fluctuating. • Unstable: Associated with abnormal clones.

  17. Degree of Severity of Acquired Aplastic Anemia

  18. Inherited Anemia Fanconi’s Anemia: • The most common type of inherited aplastic anemias. • Associated with anomalies e.g., skeletal, skin. • Autosomal recessive. • Marrow failure is at the level of CFU-GM. Genetics: • Increased sensitivity of the cells to chromosomal damage by DNA cross linking agents. • 5 genes are responsible A E. • IV54 mutation, is associated with multiple dysmorphism, severe pancytopenia, higher incidence of AML.

  19. Inherited Anemia Clinical Features: • Skeletal and skin anomalies seen at birth e.g., microcephally. • Manifestations of marrow failure, usually later at age 5-10 yrs. Present as anemia, mucusal bleeding e.g. nasal. • Chromosomal breaks.

  20. Clinical Features of Fanconi’s Anemia Common Findings: • Low birth weight • Short stature • Microcephaly • Microphthalmia • Microstomia • Skeletal abnormalities, particularly of thumbs and radii • Hypoplastic hypothenar eminences • Generalized increased pigmentation of skin

  21. PURE RED CELL APLASIA • PURE RED CELL APLASIA • Pure red cell aplasia is characterized by a selective decrease in erythroid precursor cells in the bone marrow. WBCs and platlets are unaffected. • —        Acquired • Transitory with viral or bacterial infections • Patients with hemolytic anemias may suddenly halt erythropoiesis • Patients with thymoma – T-cell mediated responses against bone marrow erythroblasts or erythropoietin are sometimes produced. • —        Congenital • Diamond-Blackfansyndrome – occurs in young children and is progressive. It is probably due to an intrinsic or regulatory defect in the committed erythroid stem cell.

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