Chronic Lymphocytic Leukemia Health Article

Causes and symptoms

The cause of CLL is unknown. It is certain, however, that CLL is linked to genetic abnormalities and environmental factors. For example, close family members of patients with CLL are twice as likely to seven times as likely to be diagnosed with CLL as people in the general population. For another example, exposure to certain chemicals used in farming and other agricultural occupations may increase the risk that a person will develop CLL. In contrast, CLL is not associated with exposure to radiation known to cause other cancers. As of 2001, doctors were unsure whether people who have had certain virus infections are more likely to develop CLL than are people in the general population. If there does turn out to be such an association, it would not be with all viruses but with two human retroviruses (HTLV-I and HTLV-II) or with Epstein-Barr virus (EBV).

The symptoms of CLL are generally vague and non-specific. One out of five patients with CLL has no symptoms at all, and the disease is discovered only through a routine blood test. A patient may experience all or some of the following symptoms:

• chronic fatigue
• weakness
• a general feeling of malaise or of things being not quite right
• swollen lymph nodes
• an enlarged spleen, which could make the patient complain of abdominal fullness
• a general feeling of ill health
• fever
• frequent bacterial or viral infections.
• unusually severe response to insect bites
• night sweats
• weight loss not due to dieting or exercise

Diagnosis

There is no screening test for CLL. If the doctor has reason to suspect leukemia, he or she will conduct a very thorough physical examination to look for enlarged lymph nodes in the neck, underarm, and pelvic region. In addition, the doctor will look to see whether the liver and spleen are enlarged. Urine and blood tests may be ordered to check for microscopic amounts of blood in the urine and to obtain a complete differential blood count. This count will give the numbers and percentages of the different cells found in the blood. An abnormal blood test might suggest leukemia. Some authorities state that CLL may be diagnosed if the number of lymphocytes in the blood exceeds a certain level.

The doctor may perform a bone marrow aspiration and biopsy to confirm the diagnosis of leukemia. During the bone marrow biopsy, a cylindrical piece of bone and marrow is removed. The tissue is generally taken out of the hipbone. These samples are sent to the laboratory for examination. In many CLL patients, more than one-fourth of the bone marrow is made up of mature lymphocytes. In addition to diagnosis, bone marrow biopsy is also conducted during the treatment phase of the disease to see if the leukemia is responding to therapy.

Some CLL patients have a condition called hypogammaglobulinemia. Immunoglobulins are normal parts of the body's immune system, the system used to fight off infection. Patients with hypogammaglobulinemia have very low levels of all of the various types of immunoglobulins.

The doctor may also conduct immunophenotyping. This involves taking a sample of the blood and looking at what types of cells of the immune system are being affected by the CLL. Approximately 19 out of 20 CLL patients have the B-cell type of CLL. Far more rare is the T-cell type of CLL. In addition, the doctor may look for abnormalities in the chromosomes of the affected cells. Chromosomes are a unit of genetic material within cells. Patients exhibiting no chromosomal abnormalities have a better prognosis than those who do have such abnormalities. If the abnormalities become more complex over time, the patient's prognosis may worsen.

Standard imaging tests such as x rays, computed tomography scans (CT scans), and magnetic resonance imaging (MRI) may be used to check whether the leukemic cells have invaded other organs of the body, such as the bones, chest, kidneys, abdomen, or brain.