Leukemia is a cancer of the blood and bone marrow, characterized by the rapid and uncontrolled growth of abnormal blood cells, often immature white blood cells. This disease begins in the bone marrow, the soft tissue inside bones where all blood cells are produced. This article explores the common initial presentation of leukemia and the steps involved in its diagnosis. Symptoms vary depending on the specific type of leukemia, and this information is not a substitute for professional medical evaluation.
The Subtle Onset: Symptoms Often Overlooked
The initial signs of leukemia are frequently vague and non-specific, often dismissed as symptoms of a common illness or the flu. A pervasive early indicator is overwhelming and persistent fatigue that does not improve with rest. This exhaustion, often accompanied by general weakness, results from anemia, a deficiency of healthy red blood cells caused by cancerous cells crowding out normal production in the bone marrow.
The inability to produce sufficient healthy red blood cells means less oxygen is delivered to tissues, leading to paleness and shortness of breath, even with minimal exertion. Another subtle symptom is the presence of low-grade, persistent fevers or a general feeling of being unwell (malaise). These fevers can indicate the body is reacting to the proliferation of abnormal blood cells or that the compromised immune system is struggling to fight off minor infections.
These early symptoms result from leukemia cells beginning to take over space inside the bone marrow. The abnormal cells serve no protective purpose and prevent the development of mature, functional red blood cells, white blood cells, and platelets. This failure of the bone marrow to output healthy cells causes the slow decline in health before more acute signs emerge.
Warning Signs That Triggered a Doctor’s Visit
Symptoms that typically prompt an urgent medical appointment relate to severe cytopenias (low blood cell counts), which manifest as noticeable physical changes. One alarming sign is easy or unexplained bruising and bleeding. This occurs due to thrombocytopenia (low platelet count), as leukemia cells suppress the bone marrow’s ability to produce these clotting factors.
The low platelet count can also lead to prolonged bleeding from minor cuts, nosebleeds, or bleeding gums. A specific manifestation is petechiae, which are tiny, pinpoint red or purple spots that appear on the skin, often on the lower legs. These spots are caused by small blood vessels (capillaries) breaking under the skin because there are not enough platelets to plug the leaks.
The suppression of healthy white blood cells results in frequent, recurrent, or prolonged infections that do not respond well to standard treatment. Infections of the respiratory or urinary tract are common, as is the development of mouth sores. Other systemic signs include unexplained bone or joint pain, especially in the long bones, caused by the physical buildup of leukemia cells within the bone marrow cavity. Significant, unintentional weight loss and drenching night sweats are also common.
The Path to Confirmation: Diagnostic Steps
A medical professional, suspecting a blood disorder based on clinical symptoms, will typically order a Complete Blood Count (CBC) as the initial screening test. The CBC measures the number and appearance of red blood cells, white blood cells, and platelets in the blood. In cases of leukemia, this test often reveals abnormalities such as an extremely high or low white blood cell count, anemia, and thrombocytopenia.
If CBC results are highly abnormal, a peripheral blood smear may be performed, examining a blood sample under a microscope for immature or abnormal leukemia cells. However, the definitive diagnosis of leukemia requires a bone marrow aspiration and biopsy. This procedure involves inserting a specialized needle, usually into the hip bone, to withdraw a small sample of the marrow fluid and solid tissue.
The bone marrow sample is analyzed by a pathologist to determine the percentage of abnormal cells present. This examination confirms the diagnosis of leukemia, identifies the specific type, and helps determine the extent of the disease. Subsequent tests, such as flow cytometry and genetic testing, analyze the surface markers and chromosomes of the cancerous cells to precisely classify the subtype, guiding treatment decisions.