The bone marrow is hypocellular or aplastic.Abstract:
Due to a decrease in pluripotent stem cells, bone marrow aplasia results in a decreased hematopoiesis which leads to pancytopenia in the peripheral blood. Chemicals (e.g. benzene), drugs (e.g. chloramphenicol), and viruses (e.g. hepatitis viruses, parvoviruses) are associated with aplastic anemia. In about 2/3 of the patients, the cause remains unknown (= idiopathic aplastic anemia).
Bone marrow aplasia that occurs unexpectedly must be distinguished from the expected bone marrow aplasia induced by chemotherapy.
Clinical picture:
As in the case of the acute leukemias, symptoms result from pancytopenia. Weakness, fatigue and palpitations result from anemia, fevers and mucositis from severe neutropenia, and a bleeding diathesis (e.g. petechiae) from thrombocytopenia.
Hematology:
All three cell lines are decreased in the peripheral blood film. The erythrocytes tend to be macrocytic. The few neutrophils that are present may show toxic abnormalities. No additional specific abnormalities are present.
Bone marrow:
The bone marrow is hypocellular or aplastic.