How Does Leukemia Affect the Body?

Leukemia is a cancer of the blood and bone marrow. It may be initially asymptomatic, but leukemia can cause fatigue, weakness, and easy bruising and bleeding, among others.

Leukemia is a cancer of the blood cells, usually the white blood cells though it can start in other types of blood cells. In patients with leukemia, the bone marrow in the center of the bones produces abnormal blood cells that grow out of control and get into the bloodstream. 

There are several types of leukemia, including:    

1. Acute lymphocytic leukemia (ALL)
2. Acute myeloid leukemia (AML)
3. Chronic lymphocytic leukemia (CLL)
4. Chronic myeloid leukemia (CML)
5. Chronic myelomonocytic leukemia (CMML) (uncommon)
6. Hairy cell leukemia (HCL)
7. Juvenile myelomonocytic leukemia (JMML) (uncommon)
8. Large granular lymphocytic (LGL) leukemia 
9. Background Blastic plasmacytoid dendritic cell neoplasm (BPDCN) [formerly called natural killer (NK) cell leukemia/lymphoma]
10. B-cell prolymphocytic leukemia (B-PLL) (very rare)
11. T-cell prolymphocytic leukemia (T-PLL) (extremely rare)

Some types of leukemia grow slowly ("chronic leukemias"), and others grow faster ("acute leukemias"). Patients may have chronic leukemia at first and that later develops into fast-growing acute leukemia.

Leukemia may not cause symptoms, especially at first. When symptoms of leukemia occur, they may include:

1. Tiredness/fatigue
2. Weakness
3. Bleeding more easily than normal
4. Getting sick from infections more easily than normal
5. Dizziness or lightheadedness
6. Shortness of breath
7. Pale skin
8. Bruises (or small red or purple spots) on the skin
9. Bleeding, such as frequent or severe nosebleeds, bleeding gums, or heavy menstrual bleeding in women
10. Clotting problems
11. Swelling in the abdomen
12. Enlarged lymph nodes
13. Bone or joint pain
14. Feeling cold
15. Headaches

Patients with leukemia may also have generalized symptoms such as:

1. Weight loss
2. Fever
3. Night sweats
4. Loss of appetite
5. Fatigue

Acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), and chronic myeloid leukemia (CML) are caused by genetic mutations. 

Some cases of chronic myelomonocytic leukemia (CMML) are linked to cancer treatment, but in most cases the cause is unknown.

Risk factors for developing acute lymphocytic leukemia (ALL) include:

• Radiation exposure
• Chemical exposure such as chemotherapy drugs and other chemicals, including benzene
• Viral infections such as human T-cell lymphoma/leukemia virus-1 (HTLV-1) (not common in the U.S.), Epstein-Barr virus (EBV) 
• Certain genetic conditions
• Age over 50
• Race/ethnicity: more common in Caucasians
• Gender: slightly more common in females
• Having an identical twin with ALL 

Possible other risk factors 

• Exposure to electromagnetic fields
  • Such as living near power lines or using cell phones;
  • This is not settled science and remains controversial in the medical community.
• Workplace exposure to diesel, gasoline, pesticides, and certain other chemicals
• Smoking
• Exposure to hair dyes

Risk factors for developing acute myeloid leukemia (AML) include:

• Getting older
• Being male
• Smoking
• Exposure to certain chemicals, such as long-term exposure to benzene 
• Certain chemotherapy drugs including alkylating agents and topoisomerase II inhibitors 
• Exposure to radiation
• Having certain blood disorders including chronic myeloproliferative disorders such as polycythemia vera, essential thrombocythemia, and idiopathic myelofibrosis
• Certain genetic syndromes
• A family history

Possible other risk factors 

• Exposure to electromagnetic fields
• Workplace exposure to diesel, gasoline, and certain other chemicals and solvents
• Exposure to herbicides or pesticides

Risk factors for developing chronic lymphocytic leukemia (CLL) include:

• Age over 50 
• Exposure to certain chemicals, such as Agent Orange, radon, and possible certain pesticides
• Family history
• Gender: slightly more common in males
• Race/ethnicity: more common in North America and Europe than in Asia.

Risk factors for developing chronic myeloid leukemia (CML) include:

• Exposure to high-dose radiation (such as being a survivor of an atomic bomb blast or nuclear reactor accident) 
• Getting older
• Gender: slightly more common in males

Risk factors for developing chronic myelomonocytic leukemia (CMML) include:

• Age: CMML is rare in people under age 40. Most cases occur in people 60 and older.
• Gender: twice as common in men as in women
• Prior cancer treatment with chemotherapy 

Leukemia is diagnosed with tests such as:

• Blood tests
  • Complete blood count (CBC) and peripheral blood smear
  • Blood chemistry tests
  • Coagulation tests
• Bone marrow aspiration and biopsy 
• Chromosome tests
• Lumbar puncture (spinal tap)
• Lymph node biopsy
• Imaging tests
  • X-rays
  • Computerized tomography (CT) scan
  • Positron emission tomography (PET) scans
  • Magnetic resonance imaging (MRI)
  • Ultrasound

Treatment for leukemia can include one or more of the following:

• Chemotherapy 
• Immunotherapy 
• Targeted therapy
• Bone marrow transplant (also called "stem cell transplant") 
• Radiation
• Surgery

Complications of leukemia may include:

• Infection
• Anemia
• Compromised immune system
• Developing a second cancer
• Death