急性白血病.ppt

Acute Leukemia
Definition
Acute leukemias are hematologic malignancies with increased numbers of myeloid or lymphoid blasts.
The term of “acute”, historically referring to a rapid onset and promptly fatal e, now indicates the relatively undifferentiated nature of the leukemic cells.
Incidence
The overall annual incidence of AL in the general population is about 4 per 100,000, with approximately 70% of them being acute myeloid leukemia (AML).
AML accounts for about 15% of childhood leukemias, and for approximately 80% to 90% of acute leukemias in adults, with median age at diagnosis being about 70 years.
Acute lymphoid leukemia (ALL) is primarily a childhood disease, with a peak incidence between the age 2 to 3 years. It diminishes in frequency until it reaches a nadir from about the ages of 25 to 50 years, after which it increases to achieve a second, but minor, peak at ages older than 80.
Etiology
The etiology of most cases is unknown, but a few patients have had previous exposure to ionizing radiation, cytotoxic chemotheraputic agents, or benzene, which are considered causes.
Several congenital diseases, such as Down syndrome, Bloom syndrome, and Turner syndrome, have an increased incidence of AML, as do certain types of born marrow failure, such as Fanconi anemia and Blackfan-Diamond syndrome.
Patients with myelodysplastic and myeloproliferative disorders have varying, but elevated risks of developing AML.
Heavy cigarette smoking also increases the incidences.
Clinical manifestations
At time of diagnosis, most patients with AL have nonspecific symptoms, such as fatigue, lethargy, and weight loss. plaints, such as dyspnea, angina, and dizziness arise from anemia.
Fever from the disease itself or from an infection related to neutropenia can be the presenting manifestation.
Bleeding, such as epistaxis or cutaneous ecchymoses, may occur from thrombocytopenia or from disseminated intravascular coagulation (DIC) in patients with acute promyelocytic leuke