There are different types of leukemia, based upon how quickly the disease develops and the type of abnormal cells produced. Leukemia is called an acute leukemia if it develops rapidly. Large numbers of leukemia cells accumulate very quickly in the blood and bone marrow, leading to symptoms such as tiredness, easy bruising, and susceptibility to infections. Acute leukemia requires fast and aggressive treatment.
Chronic leukemias develop slowly over time. These leukemias may not cause specific symptoms at the beginning of their course. If left untreated, the cells may eventually grow to high numbers, as in acute leukemias causing similar symptoms.