What is Leukemia?

Leukemia is commonly known as cancer of the blood. While that is in fact a correct definition, it would be more precise to call it a bone marrow disorder. Leukemia occurs when one abnormal white blood cell begins to clone itself; the clones do not fight infection properly, nor do they die at the same rate as other white cells, which inhibits the reproduction of healthy cells.

Acute or Chronic?

The seven main types of leukemia are classified as either acute, which progresses rapidly, or chronic, which progresses slowly. In acute leukemia, there is an abnormal growth of immature cells called “blasts.” Chronic leukemia is marked by some blast cells along with an excessive number of mature blood cells.

Leukemia is also classified according to which type of white blood cell is behaving strangely. When the lymphocytes are abnormal, it called lymphocytic or lymphoblastic leukemia. Lymphocytes are one of the five kinds of white blood cells (leukocytes) circulating in the blood. Mature lymphocytes look pretty much alike, but have different functions.

The most abundant lymphocytes are B-lymphocytes and T-lymphocytes, commonly referred to as B-cells and T-cells. B-cells are produced and grow to maturity in the bone marrow, which is why they are assigned the letter “B.” T-cells originate in the bone marrow but move on to acquire the letter “T” by maturing in the thymus.

When myelocytes are abnormal, it is called myelocytic or granulocytic leukemia. Myelocytes are also called granulocytes because of the granules found inside the cell. Neutrophils, basophils, esoinophils, and monocytes (all types of myelocytes) circulate through the blood, killing bacteria.

Acute and chronic leukemias are further subdivided into lymph-status categories. Acute can be either acute lymphocytic leukemia (ALL) or acute non-lymphocytic leukemia (ANLL). ANLL also includes other types of white cells, such as melocytes (AML).

Chronic leukemias follow suit and become chronic lymphocytic leukemia (CLL) or chronic myeloctyic leukemia (CML).

The Lymph System and Bone Marrow

Inside the large bones of the human body is a spongy tissue called bone marrow. Bone marrow makes cells called “blasts” that develop into several types of blood cells, each with a specific function.

The lymph system is made of thin tubes that branch into all parts of the body. Groups of lymph nodes (small bean shaped organs) are found along the routes. Lymph is a colorless, watery fluid containing lymphocytes that are carried by lymph vessels along the network of the system.

Most people are familiar with the fact that the underarm stores clusters of lymph nodes, but the neck, pelvis, abdomen, spleen, and a few other organs are also parts of the lymph systems. The spleen makes lymphocytes and filters old cells from the blood.

Lymphocytes make substances called antibodies, which fight off infection by attacking and digesting harmful bacteria in the body. In acute leukemias, the developing lymphocytes do not mature. They collect in the lymph tissues, causing them to sell. They make their way through the marrow and blood, crowding out the other healthy cells.

Bone marrow creates red blood cells, white blood cells, and platelets. Red blood cells carry oxygen and other materials to all body tissues, white blood cells fight infection, and platelets cause blood to clot.

If the marrow cannot produce enough red blood cells, the patient will become anemic. If the marrow cannot produce enough healthy white blood cells, the patient’s immune system becomes compromised and any minor infection can become deadly. If the marrow cannot produce enough platelets for blood to clot normally, cuts will bleed profusely and the patient will easily bruise. The cancerous lymphocytes can also invade the brain, the spinal cord, and other critical organs.

The final division into seven types of leukemia looks like this:

1) Adult Acute Lymphocytic Leukemia (Adult ALL): Too many abnormal (immature) infection-fighting lymphocytes are found in the bone marrow and blood. Often causes a shortage of platelets as well.

2) Childhood Acute Lymphocytic Leukemia (Childhood ALL): Same definition as Adult ALL. This type accounts for 85% of leukemia cases in children and is the most common type of childhood cancer. It is also the easiest to treat and has a high success rate of cures.

3) Adult Acute Myeloid Leukemia (Adult AML): Also called Acute Non-lymphocytic Leukemia (ANLL). Granulocytes do not mature and become too numerous.

4) Childhood Acute Myeloid Leukemia (Childhood AML): Same definition as the adult type.

5) Chronic Lymphocytic Leukemia (CLL): The developing white cells do not mature correctly and too many are made. This is the most common leukemia and is usually found in people sixty years of age or older.

6) Chronic Myelogenous Leukemia (CML): This disease is also called Chronic Granulocytic Leukemia. As with the AML, the granulocytes do not mature and live longer than a normal cell. In most CML patients, the genetic material of the leukemia cells has an abnormal chromosome that doesn’t go away, even after treatment is completed. It is called a Philadelphia chromosome.

7) Hairy-Cell Leukemia (HCL): With HCL, malignant cells are found in the bone marrow and blood. HCL is uncommon and characterized by an enlarged spleen without enlarged lymph nodes. HCL causes low numbers of all blood cell types.

The strange sounding (in comparison to the others) name of this leukemia comes from the appearance of the cells. Beneath the microscope, the cancerous cells look as though hair is growing around their edges.

Symptoms

The symptoms for all types of leukemia are the same. They develop and advance rapidly in cases of acute leukemia, but gradually in chronic cases, which tend to also be less severe. About 20% of the chronic patients do not exhibit symptoms at the time of diagnosis.

Symptoms common to all types of leukemia include extreme fatigue, unexplained fevers, frequent infections, night sweats, loss of appetite, weight loss, and easy bleeding or bruising.

Leukemia cells collecting in various areas of the body will produce other side effects such as seizures, muscle spasms, headaches, balance problems, vision problems, nausea and/or vomiting, shortness of breath, painful swelling in the neck, underarm, or groin area, pain in the joints and/or bones, painful testicular swelling, stomach pain, and general weakness.

Anyone experiencing these symptoms would be wise to schedule an appointment with a physician. It is important to remember that these symptoms are common to a number of diseases and do not necessarily indicate leukemia. Do not self-diagnose. If you are experiencing these symptoms, it is important that you schedule an appointment with a physician. Blood disorder specialists are called oncologists and your physician should be able to refer you to one.

Wanted: Not Dead but Alive

And remember, it is better to be a hypochondriac than a corpse. Like every other cancer, you have the best chances to beat leukemia with an early detection and prompt treatments. A decade ago, a leukemia diagnosis was a death sentence. Now, with such fantastic strides in medicinal sciences, more and more people are able to say, “I’m a leukemia survivor.” People like me.