Acute myeloid leukemia is a condition in which the bone marrow normal functioning is disturbed and it produces abnormal white blood cells called myeloblasts. This also includes red blood cells and platelets. The incidence is 2.3 per 100,000 people per year which is higher among men than women (2.9 vs 1.9). It is the most common leukemia in adults (80% of cases) with vast majority of patients who are 65 years or older.
The common causes include genetic, radiation, toxic chemical exposure and medications which include: alkylating-agents, topoisomerase-II inibitors, chloramphenicol, phenylbutazone, chloroquine and methoxypsoralen.
Symptoms experienced by person suffering from acute myeloid leukemia are nonspecific in nature and are mostly related to anemia, leukocytosis, leukopenia, leukocyte dysfunction and thrombocytopenia. Symptoms usually present for 3 months or more before diagnosis is made.
Most Common Presenting Signs:
- Fatigue (50%)
- Anorexia (30-40%)
- Weight loss (30-40%)
- Fever without evident cause (10%)
- Easy Bruising (5%)
- Bleeding (5%)
Other common signs include: bone pain, lymphadenopathy, non-specific cough, headaches, excessive diaphoresis and symptoms secondary to mass lesions (granulocytic sarcoma or chloroma).
- Sternal tenderness
- Multiple bruises
- Bleeding (gingivae most common)
- Unexplained infections
- GI bleed
- Pulmonary, intracranial, and retinal hemorrhage
Laboratory and Radiographic Work-up:
- CBC with manual differential
- Uric Acid level
- Clotting studies (PT, PTT, D-dimer, fibrinogen)
- Bone marrow aspirate and biopsy
- Chest xray
- Anemia (normochromic, normocytic)
- Leukocytosis (median = 15,000)
- Thrombocytopenia (< 100,000)
Morphology and Cytology:
- 20% myeloblasts in blood and/or bone marrow
- Auer Rods (cytoplasmic granules)
- Positive myeloperoxidase reaction in > 3% blasts
Acute myeloid leukemia is classified according to French-American-British (FAB) classification which has eight major subtypes based on morphology and cytochemistry.
Another classification is World Health Organization classification based on molecular, morphologic and clinical features.
- Age at diagnosis
- Comorbidities (acute vs chronic)
- Chromosomal findings
- Symptomatic interval preceding diagnosis
- Presenting Leukocyte count
- Circulating myeloblast count
- FAB classification
- Morphologic characteristics of the leukemic cell
Two phases of treatment include induction and post-remission. Initial goal is to quickly induce complete remission. Combination chemotherapy is used and continued low-dose post-remission therapy must be used to ensure prolonged survival. Otherwise recurrence rates can be as high as 90%.After induction chemotherapy, bone marrow biopsy is obtained. If >5% of blasts with >20% cellularity, then retreatment necessary. Stem cell transplant may be necessary if retreatment fails. Post-remission treatment involves stem cell transplant and continued supportive care which includes: Blood transfusion when platelets <20,000 and Hgb <8. Empiric antibiotic treatment is given, when fever present and allopurinol is used to treat increased uric acid levels.