|
| |
Acute Lymphoblastic
Leukemia Diagnosis
Diagnosing leukemia usually begins with a medical history and
physical examination. If there is a suspicion of leukemia, the patient will then
proceed to undergo a number of tests to establish the presence of leukemia and
its type. Patients with this constellation of symptoms will generally have had
blood tests, such as a full blood count.
These tests may include complete blood count (blasts on the blood film generally
lead to the suspicion of ALL being raised). Nevertheless, 10% have a normal
blood film, and clinical suspicion alone may be the only reason to perform a
bone marrow biopsy, which is the next step in the diagnostic process.
Bone marrow is examined for blasts, cell counts and other signs of disease.
Pathological examination, cytogenetics (e.g. presence of the Philadelphia
chromosome) and immunophenotyping establish whether the "blast" cells began from
the B lymphocytes or T lymphocytes.
If ALL has been established as a diagnosis, a lumbar puncture is generally
required to determine whether the malignant cells have invaded the central
nervous system (CNS).
Lab tests (mentioned above) and clinical information may also be used to
determine whether other medical imaging (such as ultrasound or CT scanning) may
be required to find invasion of other organs such as the lungs or liver.
Causes of Acute lymphoblastic leukemia
The etiology of ALL remains uncertain
although some doctors believe that ALL develops from a combination of genetic
and environmental factors. However, there is no definite way of determining the
cause of leukemia.
Scientific research has shown that all malignancies are due to subtle or less
subtle changes in DNA that lead to unimpaired cell division and breakdown of
inhibitory processes. In leukemias, including ALL, chromosomal translocations
occur regularly. It is thought that most translocations occur before birth
during fetal development. These translocations may trigger oncogenes to "turn
on", causing unregulated mitosis where cells divide too quickly and abnormally,
resulting in leukemia. There is little indication that propensity for ALL is
passed on from parents to children.
There have been indications that excessive exposure to high dose radiation (such
as that of nuclear reactors, notably Chernobyl, and the atomic bombs in
Hiroshima, Japan 1945) increases the risk of developing acute leukemia. There
has also been inconclusive evidence suggesting that exposure to chemicals such
as benzene can cause an increased risk for developing acute leukemia.
Acute lymphoblastic
leukemia
| |
|