Leukemia is cancer of the blood
cells. It starts in the bone marrow, the soft tissue inside most bones. Bone
marrow is where blood cells are made.
When you have leukemia, the bone marrow starts to make a
lot of abnormal white blood cells, called leukemia cells. They don't do the
work of normal white blood cells. They grow faster than normal cells, and they
don't stop growing when they should.
Over time, leukemia cells
can crowd out the normal blood cells. This can lead to serious problems such as
anemia, bleeding, and infections. Leukemia cells can
also spread to the
lymph nodes or other organs and cause swelling or
several different types of leukemia. In general, leukemia is grouped by how
fast it gets worse and what kind of white blood cell it affects.
- It may be acute or chronic. Acute leukemia gets worse very fast and may make you
feel sick right away. Chronic leukemia gets worse slowly and may not cause
symptoms for years.
- It may be lymphocytic or
myelogenous. Lymphocytic (or lymphoblastic) leukemia
affects white blood cells called lymphocytes. Myelogenous leukemia affects
the other type of cells that normally become granulocytes, red blood cells, or platelets.
The four main types of leukemia are:
There are less common leukemias, such as hairy cell leukemia. There are also subtypes of leukemia, such as acute promyelocytic leukemia (a subtype of AML).
Experts don't know what
causes leukemia. Some things may increase your risk, such as being exposed to large amounts of radiation and being exposed to certain chemicals at work, such as benzene.
Symptoms may depend on what
type of leukemia you have, but common symptoms include:
- A new lump or swollen gland in your neck, under your arm, or in
- Frequent nosebleeds, bleeding from the gums or rectum, more
frequent bruising, or very heavy menstrual bleeding.
- Frequent fevers.
- Night sweats.
- Bone pain.
- Unexplained appetite loss or recent weight loss.
- Feeling tired a lot without a known reason.
- Swelling and pain on the left side of the belly.