Chronic lymphocytic leukemia (CLL) is a slow-growing cancer that originates in the bone marrow, affecting the production and function of specific white blood cells called lymphocytes. CLL is the most common form of leukemia diagnosed in adults, primarily affecting those over the age of 55. The disease involves the uncontrolled growth and accumulation of abnormal B-cell lymphocytes. These cancerous cells begin in the bone marrow but circulate in the blood and can collect in various tissues.
How CLL is Often Discovered
CLL is often discovered before a person experiences any noticeable symptoms. Many individuals are identified as having CLL during a routine physical examination or blood work ordered for an unrelated health concern. The Complete Blood Count (CBC) test, a common part of routine blood screening, frequently reveals an elevated white blood cell count.
This increase is due to lymphocytosis, an unusually high number of circulating lymphocytes in the blood. A count of 5,000 or more monoclonal B-lymphocytes per microliter of blood for at least three months is often the defining laboratory criterion for diagnosis.
General Systemic Symptoms
When chronic lymphocytic leukemia progresses, it can trigger non-specific, body-wide symptoms often referred to as “B symptoms.” These constitutional symptoms are a sign of the disease’s metabolic activity and can indicate the need to initiate treatment. One of the most common complaints is persistent, profound fatigue that does not improve with rest.
Unexplained weight loss is another systemic symptom. Patients may also experience drenching night sweats, which are severe enough to soak clothing or bedding. A recurring fever, specifically a temperature above 100.4°F (38°C) lasting for two weeks or more in the absence of infection, is also considered a B symptom.
Symptoms Related to Low Blood Counts
The accumulation of cancerous lymphocytes in the bone marrow eventually crowds out the normal blood-producing cells, a process called bone marrow failure. This leads to deficiencies in healthy blood components, causing specific physical symptoms. A low red blood cell count, known as anemia, results in the body’s tissues not receiving enough oxygen. This oxygen deprivation manifests as extreme tiredness, general weakness, pale skin, and shortness of breath, particularly with physical exertion.
A deficiency in platelets, called thrombocytopenia, impairs the blood’s ability to clot effectively. This condition causes symptoms like easy bruising, frequent nosebleeds, bleeding gums, and the appearance of petechiae—tiny, pinpoint red or purple spots on the skin caused by small hemorrhages.
Additionally, the body may experience neutropenia, which is a reduction in functional neutrophils, a type of white blood cell necessary for fighting bacterial infections. While the overall white blood cell count may be high due to the excess of dysfunctional lymphocytes, the lack of healthy neutrophils leaves the body vulnerable to frequent or unusually severe infections.
Physical Signs of Lymphocyte Accumulation
As the abnormal lymphocytes multiply, they accumulate outside the bone marrow, creating physical signs that can be detected during an examination. The most common physical finding is lymphadenopathy, which is the swelling of lymph nodes in the neck, armpits, or groin. These enlarged nodes are typically painless, firm, and rubbery to the touch, distinguishing them from the tender swelling often associated with an infection.
Lymphocyte accumulation can also cause the enlargement of the spleen, a condition known as splenomegaly, which occurs in the upper left part of the abdomen. An enlarged spleen may cause a feeling of abdominal fullness, discomfort, or sometimes pain under the left ribs, often making a person feel prematurely full after eating. Less frequently, the liver may also become enlarged (hepatomegaly) due to the infiltration of leukemic cells.