Definition

Leukemia is a cancer of the blood cells. In cancer, cells become abnormal and grow out of control. As the number of abnormal blood cells increase, the healthy blood cells are outnumbered. There are three main types of blood cells. Each has a distinct job:

• White blood cells (WBC), also called lymphocytes, are most often involved in leukemia. WBCs are components of the immune system.
• Red blood cells (RBC) carry oxygen throughout the body.
• Platelets help the blood clot at injury sites.

Leukemia cells cannot do the job of normal blood cells. This causes many of the symptoms of leukemia. The disease starts in the bone marrow where blood cells are made. The most common types of leukemia in children are:

• Acute lymphoblastic leukemia (ALL)
• Acute myeloid leukemia (AML)

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Causes

Cancer occurs when cells in the body divide without control or order. Normally, cells divide in a regulated manner. If cells keep dividing uncontrollably when new cells are not needed, a mass of tissue forms. The term cancer refers to malignant growth of cells or tissue. These growths can invade nearby tissues. Cancer that has invaded nearby tissues can then spread to the blood and other parts of the body.

It is not clear exactly what causes these problems in the cells, but it is probably a combination of genetics and environment.

Risk Factors

Factors that may increase your child's chances of leukemia:

• Exposure to some environmental and chemical factors such as:
  • Chronic exposure to benzene that exceeds federally approved safety limits.
  • Some chemotherapy drugs
  • High doses of radiation therapy
• Having a sibling, especially an identical twin, who develops leukemia
• Having a genetic condition, such as Down syndrome, Li-Fraumeni syndrome, Klinefelter syndrome, Wiskott-Aldrich syndrome, ataxia-telangiectasia, neurofibromatosis, or Fanconi anemia

Symptoms

Leukemia may cause:

• Bleeding or bruising—may appear as tiny red spots
• Acute or recurrent infections—may have fever, chills, and a cough
• Bone and joint pain
• Abdominal pain
• Weight loss, loss of appetite
• Swollen lymph nodes, swelling of the liver or spleen
• Difficulty breathing
• Rash, gum problems
• Weakness and fatigue
• Pale skin
• Shortness of breath
• Decreased energy

Diagnosis

The doctor will ask about your child’s symptoms and medical history. A physical exam will be done. The doctor will check for swelling of the liver, spleen, and lymph nodes. Leukemia can be diagnosed by identifying abnormal cells in the blood. Further testing is done to identify specific details and locations of the lymphocytic cells to determine treatment. Tests include:

• Blood tests—to measure the number and type of blood cells
• Bone marrow biopsy —a sample of bone marrow is removed and tested for the presence of cancer
• Lumbar puncture —tests the fluid that surrounds the brain and spinal cord for the presence of cancer

Imaging tests may be done to look for spreading of the tumor, infections, or injuries caused by leukemia:

• CT scan
• X-ray
• Ultrasound
• MRI scan

Treatment

Symptoms created by leukemia may need to be treated first. Treatment may include:

• Antibiotics to treat infections
• Blood transfusion to treat severe anemia or bleeding
• Emergency treatment if there are too many leukemia cells or the leukemia cells are dying too quickly

Treatment is determined by the specific type of leukemia cell identified by testing. Treatment may one or a combination of the treatments below:

Prevention

There are no current guidelines to prevent leukemia in children because the cause is unknown.