Leukemias are cancerous blood diseases, characterized by an abnormal proliferation of the cells found in bone marrow. Acute leukemia affects children in the majority of cases, although adults can also be affected. It affects the production of "immature" white blood cells, i.e. cells that have not fully completed their normal development. These immature cells, called blasts, will proliferate uncontrollably in the bone marrow, preventing the proper production of other cells there within. They will eventually invade the blood. In the vast majority of cases, no cause is found, but leukemia is most frequently observed in connection with certain other diseases of the spinal cord or in the context of exposure to toxic substances or drugs.
Acute leukemia is characterized by a rapid increase in blast cells of the bone marrow. Symptoms appear very quickly, and some are secondary to a deficiency in normal blood constituents:
- fatigue and paleness due to anemia, decreased red blood cells;
- consecutive bleeding in thrombocytopenia, decreased platelets;
- exposure to infections due to leukopenia, decreased white blood cells.
Other signs are frequently present:
- Increase in the size of lymph nodes, called lymphadenopathy or adenomegaly, and the spleen, called splenomegaly;
- skin lesions.
Diagnosis is based on several practical exams:
- a blood test with CBC (or blood count, NFS), showing leucopenia, anemia, thrombocytopenia;
- a blood smear showing an unusually high number of blasts;
- a bone marrow aspiration, confirming the diagnosis by finding many immature cells;
- other investigations allow us to characterize more precisely the type of leukemia, and mainly serve to adapt the treatment.
Treatment requires hospitalization. It takes place in several phases:
- a sterile hospital room with impeccable hygiene;
- an initial chemotherapy combination of several drug treatments that aims to eliminate proliferating cells. The patient quickly loses his entire immune system, hence the importance of sterile isolation, since he becomes very sensitive to even the slightest infection. This phase lasts about a month.
- then, outpatient therapy, with chemotherapy continued, but at lower doses. Healing can sometimes occur at this stage.
- if not, new chemotherapy sessions are conducted in a sterile room, and hematopoietic stem cells, which are cells of normal bone, are grafted.
Bone marrow transplantation is a delicate operation. The risk of rejection is present, despite the decline in immune system of the patient.