Clinical Maneuvers Of Hematopoiesis And Special Forms Of Aplastic Anemia
Danielle: A Child Affected With Diamond- Blackfan syndrome
Special forms of Aplastic Anemia
The term constitutional aplastic anemia is used to denote congenital, genetic or familial aplastic anemias.
Fanconi’s anemia (Congenital Pancytopenia)
In this syndrome, congenital abnormalities like hyperpigmentation, absence or bypoplasia of the thumbs and radii, strabismus, mental retardation, deafness and dwarfism are seen. Pancytopenia and bone marrow hypoplasia develop by the age 5-10 years. The defect leading to pancytopenia appears to be at the level of the stem cells. Androgens and corticosteroids are more effective in Fanconi’s anemia. Androgen therapy may have to be continued for a few years, depending on the response.
‘Pure red cell” Aplasia (PRCA)
Aplasia is confined to the erythroid elements. These subjects are anemic, reticulocytopenic and with decreased erythropoietic activity in bone marrow.
Red cell aplasia may be acquired in different conditions. These include aplastic crises in chronic hemolytic anemias, infection, malnutrition, renal failure, systemic lupus erythematosis, neoplasms and the use of several drugs. Pure red cell aplasia is more common above the age of fifty years. Approximately half the patients, mainly women with PRCA have thymoma. In the rest, the condition is primary. In those with thymoma, immune mechanisms may play a role and thymectomy corrects the anemia. Other modalities of treatment include adrenal steroid, androgens and immunosuppressive agents.
Congenital hypoplastic anemia (Diamond- Blackfan syndrome)
Congenital hypoplastic anemia is a normochromic normocytic anemia with reticulocytopenia which is inherited as autosomal recessive. Leucocytes and platelets are generally normal. Bone marrow shows selective erythroid hypoplasia. About 80% cases are diagnosed within six months of life. One-third of the patients may have mild physical abnormalities. The course is variable with insidious progression in some and spontaneous remission in others. Management is on the lines described for aplastic anemia.
Treating Aplastic Anemia
Pure Cell Red Aplasia In Blood Stream
Stimulation of hematopoiesis
Semisynthetic androgens like oxymethalone are active in stimulating cell proliferation and they are effective in approximately 50% of mild and moderate cases. The dose is 2-3 mg/Kg/day orally, given for at least 3 months before abandoning the drug. Adverse side effects include weight gain, fluid retention, virilisation, cholestatic jaundice and amenorrhea. Corticosteroids have been employed from time to time, but there value is not proved beyond doubt. Moreover, since glucocorticoids increase the susceptibility to infection, they should not be used indiscriminately.
Lithium carbonate has been known to stimulate granulopoiesis. It has been tried in aplastic anemia. The results are encouraging, though the drug is still only, experimental.
Transplantation of hematopoietic stem cells
In recent years, bone marrow transplantation has been accepted as the definitive treatment of aplastic anemia not responding to medical treatment. This is successful in 60% of cases. The HLA- matched donor marrow is used and 2.6 X 108 cells/Kg body weight are infused. Sibling marrow is ideal, but when this is not available, unrelated donors can be selected. Bone marrow transplantation is more successful in persons below the age of 30 years. The donor marrow starts to function in 2-4 weeks. Complications include infection and graft versus host disease (GVHD). The latter is produced by the immunocompetent cells of the donor marrow which initiate immunological responses against the host’s tissues.
Adverse effects are seen on the skin, gastrointestinal tract, liver hematopoietic tissue, lymphoid tissues, heart and lungs. Use of immunosuppressant drugs, especially cyclosporine A, can prevent GVHD to some extent. Efforts are being made in premier institutions in developing countries to make this procedure available.
© 2014 Funom Theophilus Makama