Leukemia: Definition, Classification, Symptoms, Clinical Features

What is Leukemia?

     Leukemia is the neoplastic proliferation of hematopoietic precursors cells. It is the cancer of blood-forming tissues, originates from the Bone marrow, and infiltrates the bone marrow. Leukemia involves the bone marrow, Peripheral blood also infiltrates the spleen, liver, and lymph nodes.

Why Leukemia occurs?

     Leukemia is a polyetiologic disease. Leukemia occurs due to mutations in the cells that make up the bone marrow, and mutations are called Leukemic changes, which lead to the rapid proliferation of that cells. The mutagenic factors are like Viruses, Radiations, Chemical substances, and hereditary factors.

Classification of Leukemia

     Leukemia is classified on the basis of Cell differentiation and Origination:

1) Classification according to the Cell differentiation

     According to cell differentiation, leukemia is divided into two types, which are given below:

• Acute Leukemia
• Chronic Leukemia

2) Classification according to the Cell origination

     According to the cell origination, leukemia is divided into two types, which are given below:

• Myeloid Leukemia
• Lymphoid Leukemia

Types of Leukemia

     On the basis of classification, leukemia is divided into four types, that are given below:

• Acute Myeloid Leukemia
• Acute Lymphoid Leukemia
• Chronic Myeloid Leukemia
• Chronic Lymphoid Leukemia

Acute Myeloid Leukemia

     Acute Myeloid leukemia is a malignant disease of myeloblast cells, characterized by their abnormal proliferation in the bone marrow. The cells are arrested in the early stage in this disorder. 45% of all leukemias are Acute Myeloid leukemia, further 80-90% of all acute leukemia are Acute myeloid leukemia.

Acute Lymphoblastic Leukemia

     Acute lymphoblastic leukemia is characterized by the proliferation of lymphoblasts in the bone marrow. It is the cancer of lymphoid blood cells where the immature lymphocytes are developed.

The acute lymphoblastic leukemia ma y be divided into following three types:

1. Acute Lymphoblastic Leukemia-1
2. Acute Lymphoblastic Leukemia-2
3. Acute Lymphoblastic Leukemia-3

Symptoms and Clinical features of Acute Leukemia

     The clinical features of acute leukemia include Anemia, Splenomegaly, Hepatomegaly, Lymphadenopathy. As the patients with acute leukemia present with weakness, fever, pallor, breath shortness, bone pain, and night sweats.

Chronic Myeloid Leukemia

     The type of leukemia, characterized by increased and irregular growth of myeloid cells. Chronic myeloid leukemia is a malignant tumor of multipotent stem cells with a predominance of mature granulocytes and their precursors, accumulating in excess in Bone marrow and blood.

What are the phases of Chronic Myeloid Leukemia?

There are three phases of Chronic Myeloid Leukemia, that are explained below:

1. Chronic Phase: It is the initial phase, that is the stable one and lasts for 2-4 years.
2. Accelerated Phase: This phase is of 6-12 months, and patients in this phase have 10-19% blasts in blood and bone marrow, while 20% of basophils are there.
3. Blast Phase: This stage is similar to acute leukemia, and lasts for 2-4 months. This stage is also called blast crisis. In this phase, there are 20% or more than it blasts are in blood and bone marrow.

Chronic Lymphocytic Leukemia

     This type of leukemia is characterized by the proliferation of mature appearing but functionally incompetent lymphocytes in bone marrow, peripheral blood and various other organs.

     The accumulation of small lymphocytes in bone marrow, spleen, lymph nodes, and liver causes lymphadenopathy and splenomegaly late. Hypogammaglobulinemia, also common late in disease.

What are smudge cells?

     The smudge cells are the characteristics of Chronic Lymphocytic Leukemia. These cells are generally small and more fragile. These cells are also called as Basket cells.

Symptoms of Chronic Leukemia

     Mostly the chronic leukemia is asymptomatic. At larger stages the signs and symptoms will be more like those of Acute Leukemia. The symptoms include weakness, weight loss, chills, fever, swollen lymph nodes, etc.

Conclusion

     The conclusion of the whole article is that leukemia is classified on the basis of two changes that are cell differentiation and cell origination. Then these classification leads to the four types that are acute myeloid leukemia, acute lymphoid leukemia, chronic myeloid leukemia, and chronic lymphoid leukemia. These all are the cancers of the blood.