LEUKAEMIA, TYPES AND DIAGNOSIS

LEUKAEMIA DEFINITION

The word LEUKEMIA – is derived from the Greek word. ‘Leukos’ means white and ‘aima‘ means blood. Generally, the blood-forming cells are affected by this disease. In other words, Leukaemia is a group of cancers that begins usually in the bone marrow and results in a high number of abnormal WBC. However, these white blood cells are not fully developed and are called blasts or leukaemia cells.

It is a group of malignant disorders affecting the blood and blood forming tissue of the bone marrow, lymph system and spleen.

Symptoms

Symptoms may include:

• bleeding and bruising problems,
• feeling tired,
• fever, and
• an increased risk of infections.

These symptoms occur due to a lack of normal blood cells. Diagnosis is typically made by blood tests or bone marrow biopsy.

FUNCTION OF THE BONE MARROW

The bone marrow is present inside the bones. The bone marrow in the large bones of adults produce blood cells. Chiefly, 20% of our total body weight consists of bone marrow.

There are two types of bone marrow:

• Red marrow, made up mainly of myeloid tissue.
• Yellow marrow, made up mainly of fat cells.

Red marrow

Red marrow can be found in flat bones such as breast bone, skull, vertebrae, shoulder blades, hip bones, and ribs. Also, red marrow can be found at the end of long bones. For example, the humerus and femur. In addition, WBC, RBC, platelets are formed in the red marrow.

Yellow marrow

Unlike red marrow, yellow marrow is present inside of the middle section of long bones. If a person loses a lot of blood, the body can convert yellow marrow to red marrow, in order to raise blood cell production.

AETIOLOGY

There is no single known cause for any of the different types of leukaemia, because for most cases of leukaemia, a cause is unknown.

Like other cancers, Leukaemia, results from a mutation in the DNA. These mutations may occur spontaneously or as a result of exposure to radiation or carcinogenic substances.

Leukaemia causes

The exact cause of leukaemia is unknown. However, different kinds of leukaemia are believed to have different causes. Both inherited and environmental (non-inherited) factors are believed to be involved. Risk factors include smoking, ionizing radiation, some chemicals (such as benzene), prior chemotherapy, and Down syndrome. Also, people with a family history of leukaemia are at higher risk.

Other causes may include such as:

• Combination of predisposing factors including genetic and environmental influences.
• Chronic exposure to chemicals such as benzene.
• Radiation exposure (among adults).
• Cytotoxic therapy of breast, lung and testicular cancer.
• Congenital anomaly e.g., people with down syndrome have significant risk of developing acute forms of leukemia.
• The presence of primary immunodeficiency and infection with the human T- cell leukaemia virus type-1.

TYPES OF LEUKAEMIA

ACUTE LEUKAEMIA:

Predominant cells in blood and bone marrow are blast cells. It is of three types:

• Acute myeloblastic leukaemia
• an acute lymphoblastic leukaemia
• acute monoblastic leukaemia.

Acute leukaemia is characterized by a rapid increase in the number of immature blood cells. In addition, Acute leukaemia gets worse very fast and may make feel sick right away. The crowding which results from such cells makes the bone marrow unable to produce healthy blood cells.

Undeniably, immediate treatment is required in acute leukaemia because of rapid progression and accumulation of the malignant cells, which can spill into the bloodstream and spread to other organs of the body.

Particularly, acute forms of leukaemia are the most common forms of leukaemia in children.

CHRONIC LEUKAEMIA

Cells in blood and bone marrow are partly mature mostly cyte cells and few blast cells. It is of following types-

• Chronic myeloblastic (myelogenous) leukaemia
• and, Chronic lymphoblastic (lymphocytic) leukaemia.

Chronic leukaemia is characterized by the excessive buildup of relatively mature unsettled abnormal WBC. Also, Chronic leukaemia may get worse slowly and may not cause symptoms for years.

Chronic leukemia mostly occurs in older people but can occur in any age group.

Patients are treated only when symptoms, particularly anemia, thrombocytopenia, enlarged lymph nodes and spleen occur.

If the cancerous transformation occurs in the type of marrow that makes lymphocytes (infection fighting immune system cells), the disease is called lymphocytic leukaemia.

If the cancerous transformation occurs in the type of marrow cells that produce RBC, other type of WBC, & platelets, the disease is called myelogenous leukaemia.

CLINICAL FEATURES:

ACUTE LEUKAEMIA

• Weakness due to anaemia
• Fever due to secondary infections
• Gum bleeding, petechiae due to low platelets
• Sternal tenderness or bone pain due to marrow expansion and bone resorption.
• Splenomegaly (enlargement of the spleen)
• Hepatomegaly (Enlargement of the liver)
• Severe headache, Vomiting, Blurring of vision
• Acute leukaemia is of sudden onset and progress of the disease is rapid.
• Lymphoblastic leukaemia is usually a disease of childhood
• Acute myeloblastic leukaemia is a disease of adults.

BLOOD PICTURE IN ACUTE LEUKEMIA:

• T L C=25000-200000/cmm
• Total platelets-40,000-60,000/cmm
• Haemoglobin-8-9 gm%
• Bleeding time-prolonged due to low platelets
• Clotting time is prolonged due to low fibrinogen
• Bone marrow is hyper cellular with increased synthesis of blast cells.

CHRONIC LEUKEMIA:

• Onset is slow. It is usually a disease of adults
• Weakness
• Weight loss
• Fever
• Night sweats
• Lymph nodes enlargement
• Splenomegaly
• Hepatomegaly

Most common symptoms of leukemia in children is bruising, pale skin, fever and enlarged lymph or spleen.

Damage to the bone marrow cells with high number of immature WBC, results in lack of platelets, which are imp. In the blood clotting process. This means people with leukemia may easily become bruised, bleed excessively or develop pin prick blood, petachae.

WBC which are involved with fighting pathogen may be suppressed or dysfunctional. This could cause the patient’s immune system to be unable to fight off a simple infection, because leukemia prevents the immune system from working normally.

Some patients experience frequent infections, ranging from infected tonsils, sores in the mouth or diarrhea to life threatening uremia or opportunistic infection.

Some patients experience symptoms such as feeling sick, having fever, chills, night sweats and other flu like symptoms.

BLOOD PICTURE IN CHRONIC LEUKEMIA:

• TLC-200,000-400,000/cmm
• TOTAL PLATELETS-2-4 LACKS/CMM
• Haemoglobin-8-10g%
• Bone marrow is hyper cellular. Philadelphia chromosomes (an abnormal chromosomes) is a characteristic feature.

DIAGNOSIS

• repeated blood counts,
• bone marrow examination,
• Lymph node biopsy,
• Blood chemistry tests can be used to determine the degree of liver and kidney damage.

When concerns arise about other damage due to leukemia, docs may use:

• X ray
• MRI
• Ultrasound (USD).

These can show leukemia effect on body parts such as bones [x ray], the brain [MRI], or the kidneys, spleen and liver [USD].

MEDICAL MANAGEMENT

• Watchful waiting: Chronic leukaemia without symptoms, may not need cancer treatment right away. Watch for health closely so that treatment can start when it begins to have symptoms.
• Chemotherapy: people with acute leukaemia need to be treated right away. The goal of treatment is to remove signs of leukaemia in the body and make symptoms go away. This is called remission. After people go into remission, more therapy may be given to prevent a relapse.
• Targeted therapy: This affects only tumor cells and spare normal cells. Hence decreasing the associated toxicity.
• Radiation therapy,
• Stem cell transplant: Its goal is to:
  • totally eliminate leukemic cells from the body using combinations of chemotherapy with or without total body irradiation.
  • Eradicate patient’s hematopoietic stem cells,
  • replaced with those of HLA- matched (human-leukocyte antigen) from: sibling/ volunteer/ identical twin/ patients own stem cells removed before.

The choice of treatment depends mainly on the following:

• Type of leukemia (acute or chronic),
• Age,
• Whether leukemia cells were found in cerebrospinal fluid.

LIFESTYLE MANAGEMENT

• Take care of eating well and staying as active.
• Right amount of calories to maintain a good weight, enough protein,
• Regular checkups after treatment of leukemia.