Acute myelocytic leukemia
Overview
Acute myelocytic leukemia is a cancer of the blood-forming tissues of the bone marrow involving the proliferation of cells that normally develop into infection-fighting cells such as eosinophils, monocytes, basophils and neutrophils. The cancerous cells replace the normal bone marrow cells. Acute leukemia involves a more rapid proliferation of cancer cells compared to chronic forms of leukemia.
Symptoms
- Asthenia
- Pallor
- Fever
- Dizziness
- Respiratory symptoms
- Easy bruising
- Excessive bleeding
- Coagulation disorders
- Neurological disorders
- Enlarged gums
- Severe thrombocytopenia
- Bleeding gums
- Prolonged menstrual bleeding
- Weakness
- Fatigue
- Palpitations
- Bone pain
- Abdominal pain
- Headache
- Chest pain
- Shortness of breath
- Urination pain
- Enlarged liver
- Enlarged spleen
- Weight loss
Causes
Research on predisposing factors isn't conclusive but points to some combination of viruses (viral remnants have been found in leukemic cells), genetic and immunologic factors, and exposure to radiation and certain chemicals. (See Predisposing factors to acute leukemia.) Pathogenesis isn't clearly understood, but immature, nonfunctioning WBCs appear to accumulate first in the tissue where they originate (lymphocytes in lymph tissue, granulocytes in bone marrow). These immature WBCs then spill into the bloodstream and from there infiltrate other tissues, eventually causing organ malfunction because of encroachment or hemorrhage. Acute leukemia is more common in males than in females, in whites (especially people of Jewish descent), in children (between ages 2 and 5; 80% of all leukemias in this age-group are ALL), and in people who live in urban and industrialized areas. Acute leukemia accounts for 20% of all adult leukemias. Among children, however, it's the most common form of cancer. Incidence is 6 out of every 100,000 people.
Treatment
Systemic chemotherapy includes alkylating agents — usually chlorambucil, cyclophosphamide, vincristine, or fludarabine (singly or in combination) — and steroids (prednisone) when autoimmune hemolytic anemia or thrombocytopenia occurs. An advance in the treatment of CLL has been the emergence of the humanized monoclonal antibodies rituximab and alemtuzumab. Alemtuzumab acts as an antibody against the surface of CLL cells and is used when fludarabine fails. Rituximab, a monoclonal antibody, acts similiarly to alemtuzumab; studies are ongoing. When chronic lymphocytic leukemia causes obstruction or organ impairment or enlargement, local radiation treatment can be used to reduce organ size. Allopurinol can be given to prevent hyperuricemia, a relatively uncommon finding. Prognosis is poor if anemia, thrombocytopenia, neutropenia, bulky lymphadenopathy, and severe lymphocytosis are present.