Literally, leukemia means white ("leuk") blood ("emia"). White blood cells (also known as leukocytes) are actually an important part of the body’s defense mechanism. Leukemia is any disease in which the body makes too many white blood cells. Acute lymphoblastic or lymphocytic leukemia (ALL) is a malignant neoplasm of blood-forming tissues.
Lymphoblasts and prolymphocytes are immature white blood cells in the initial and middle stages of the development respectively. In acute lymphoblastic leukemia, the lymphoblasts and prolymphocytes within the bone marrow, instead of maturing into normal cells, divide and replicate in an immature and non-functional form, circulating through the blood stream and entering into the body organs. They rapidly become space-occupying and start to crowd out hematopoietic stem cells (Hematopoietic cells are the normal, healthy precursors of red blood cells, lymphocytes, erythrocytes, platelets, eosinophils, neutrophils, macrophages and mast cells). This results in reduction of normal red and white blood cells in the body.
Due to reduction of normal blood cells and increase in the malignant cells thorughout the body, the dog displays symptoms of decreased appetite, weight loss, lethargy and fatigue. Other, more specific symptoms include
The appearance of tiny purple or red spots on the skin (as the result of tiny hemorrhages of blood vessels)
Enlargement or inflammation of the spleen, lymph nodes and liver
Paling of the gums and mucous membranes
Increased thirst and increased urination
The prefix ‘acute’ in the case of leukemia has nothing to do with the normal understanding of the term (a sudden development of a disease). The acute condition in this case refers to abnormal multiplication of immature leukocytes and chronic conditions to that of developed cells. Acute lymphoblastic leukemia is more malignant than chronic.
