Acute Myeloid Leukemia (AML)

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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). 

Physical Findings:

  • Fever
  • Splenomegaly
  • 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
  • Echocardiogram

Hematological Findings:

  • 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

Classification/Subtypes:

Acute myeloid leukemia is classified according to French-American-British (FAB) classification which has eight major subtypes based on morphology and cytochemistry.

FAB classification

Another classification is World Health Organization classification based on molecular, morphologic and clinical features.

Prognostic Factors:

  •  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

Treatment:

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.

2 COMMENTS

  1. I’m a parent with a child diagnosed with AML(M2). Looking at your FAB chart, it indicates that people with M2 type have the t(8:21) and/or t(6:9). I wanted to let you know that my child has a normal karyotype. In the passage, “platelets >20,000 and Hgb >8”, the “greater than” (>) symbol needs to be replaced with the “Less than” (<) symbol.
    Including information on FLT3 might benefit others as well.

    • Hi I hope you are doing great Carey. We pray that your child gets well soon. Thank you for pointing out the typing error in the text, its through our reader’s support we are able to improve each day. We will look into adding more information regarding FLT3, at the moment, we are focusing on trying to keep it as simple as possible, so its easy to understand by general public.

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