What is leukaemia?
Leukaemia is a type of cancer that affects the white blood cells called leukocytes. Blood contains three types of cells – red blood cells or RBC’s that carry oxygen, leukocytes or white blood cells, WBC’s that help to protect the body against infections and platelets cells that help in blood clotting. These blood cells are produced in the bone marrow that is present in the cavities in bones. The leukocytes are of different kinds and various types of leukaemia are named after the kind of leukocyte affected.
What are the different types of leukaemia?
Leukaemia may be acute or chronic. The former develops suddenly and with rapidly worsening symptoms, and the latter spreads slowly over a period of time. Examples of acute leukaemia are:
Acute myelocytic leukaemia (AML) – it occurs in adults and in children less than a year old. Caused by a rapid increase in immature WBC’s, AML is characterised by bleeding from the gums and nose, proneness to fatigue and joint pain. Due to decrease in the production of RBC’s by the marrow, anaemia may occur. Patients often have enlarged lymph nodes.
Acute lymphocytic leukaemia (ALL) – this is the most common form of leukaemia in children aged 3 to 7 years. It is a progressively harmful disease where the WBC’s do not mature fully and thus are unable to carry out their functions properly. These cells multiply and replace the normal cells till finally bone marrow failure occurs. The child is prone to infections due to lowered immunity and bleeds easily if injured due to the blood’s decreased capacity to clot. He may also get tired very easily hampering his normal routine.
Examples of chronic leukaemia are:
Chronic lymphocytic leukaemia (CLL) – this is the commonest variety of leukaemia and occurs mostly in people over the age of 50. The symptoms are not very sudden and are usually vague, so the person may not seek treatment till very late. It is usually detected in a routine blood test since the person may not show any symptoms. It is caused due to a slow but steady increase in the number of WBC’s in the blood.
Chronic myelogenous leukaemia (CML) – associated with a chromosomal abnormality, CML commonly occurs in people between the ages of 35 and 60 years and is characterised by a chronic phase which can turn acute suddenly. There is no known prevention at this time but chemotherapy is started as soon as the disease is identified.
How is leukaemia caused?
The causes of most types of leukaemia are not clearly known. Some of the possible causes may be:
Exposure to harmful radiation in large doses
Exposure to certain chemicals like benzene over a long period of time
Certain genetic defects
Exposure to certain viruses (called retroviruses) that may cause leukaemia.
What are the symptoms?
The symptoms in chronic forms of leukaemia may not appear for a long time and the person may be able to lead a normal life. However, acute leukaemia presents with symptoms like:
Fatigue associated with anaemia due to the lowered number of cells which carry oxygen
Paleness of the face
Continuous low grade fever
Bleeding from gums or nose due to decrease in the number of platelets
Vulnerability to infection due to lowered immunity
Appearance of small red marks or petechiae (blood clots in the skin)
Abnormal menstruation in women
Unexpected loss of weight with loss of appetite.
How is it diagnosed?
Chronic leukaemias are diagnosed mostly when the patient goes in for a routine blood test and the sample shows an abnormal amount of WBC’s. Subsequently, specialised tests may be done to determine the exact type of leukaemia. A bone marrow biopsy in which the bone marrow is sampled using a needle, confirms the presence of leukaemia.
In acute forms, the patient may seek medical help when he feels excessively tired and loses appetite. The above tests confirm the diagnosis.
What is the treatment?
The treatment of leukaemia usually involves intensive chemotherapy using drugs that kill the cancerous cells. The drugs are given as injections into the veins or by mouth; they are given at regular intervals over a period of time. They are very powerful and result in loss of hair and symptoms like nausea and loss of appetite.
In some cases of leukaemia, especially in children, bone marrow transplant may be done. This is an expensive procedure where a person’s diseased marrow is replaced by a healthy marrow from a matching donor. This matching is very important since the body rejects foreign marrow very easily.
What are the side effects of treatment?
Chemotherapy is a very powerful form of therapy and results in loss of hair. It also damages normal cells in the bone marrow thus making it weak and highly prone to infections. Sometimes these infections can be life threatening. The person may also bleed very easily due to the destruction of platelets. Other associated symptoms like nausea, tiredness and anaemia are also common.
After treatment, the patient may recover normal functioning depending on the severity of the disease. 50% of the patients lead a normal and disease free life after a bone marrow transplant. However, the disease can recur any time and thus regular monitoring is required. This monitoring will reduce in frequency as time passes and the patient ceases to show any symptoms of recurrence of the condition.