Myeloproliferative disorders

causes

General: Myeloproliferative disorders occur when the body produces too many of one or more types of blood cells. However, the reason for this remains unknown. Researchers believe that genetics and/or the environment may play a role in the development of these disorders.
Genetics: Some people with chronic myelogenous leukemia (CML) have been shown to have a shortened chromosome, called the Philadelphia chromosome. Chromosomes contain a person's genetic makeup, called DNA. This abnormality suggests that genetics may play a role in some types of myeloproliferative disorders.

diagnosis

General: A myeloproliferative disorder may be suspected if a patient has symptoms of one of these disorders. The most common symptom noticed during a physical examination is an enlarged spleen. A doctor may then perform blood tests and a bone marrow biopsy to confirm a diagnosis.
Blood tests: A complete blood count can determine if a person has high or low levels of certain types of blood cells, including red blood cells, white blood cells, and platelets. They can also detect anemia (low levels of red blood cells) and leukemia (abnormal white blood cells that divide uncontrollably).
Bone marrow biopsy: If a myeloproliferative disorder is suspected and there are abnormalities in a person's blood, a bone marrow biopsy may be performed to confirm a diagnosis. During this procedure, a thin needle with a syringe attachment is used to collect a small sample of liquid bone marrow from the hip bone. A larger needle is then inserted to remove a tiny piece of bone marrow. The individual is usually awake during the procedure, but local anesthetics (such as lidocaine) and sedatives (such as midazolam or Versed®) may be given to reduce pain. The samples are then analyzed to determine if there are abnormal types or numbers of blood cells.

signs and symptoms

General: Many patients with myeloproliferative disorders do not have any symptoms, and they are often diagnosed during a routine examination. Nearly all types of myeloproliferative disorders (except essential thrombocytosis) may cause an enlarged spleen, because the extra blood cells are stored in this organ. An enlarged spleen often causes symptoms of abdominal pain and a feeling of fullness.
Chronic myelogenous leukemia (CML): Early symptoms of chronic myelogenous leukemia (CML) may include fever, weight loss or decreased appetite, fatigue, pain or fullness in the left side of the abdomen, and night sweats.
In the more advanced stages of the disease, patients may have shortness of breath, anemia, enlarged spleen, pale skin, frequent infections, increased risk of bleeding, bruising easily, bone pain, joint pain, or small purple or red dots on the skin (called petechiae).
Essential thrombocytosis: Symptoms of essential thrombocytosis may include headache, burning or throbbing pain in the skin, bruising easily, swelling in the hands and feet, and gastrointestinal bleeding (which may be indicated by blood in the stools)
Myelofibrosis: Symptoms of primary myelofibrosis may include fatigue, general feeling of discomfort, difficulty breathing, weight loss, fever and night sweats, anemia, and abnormal bleeding.
Polycythemia vera: Symptoms of polycythemia vera may include fatigue, general feeling of discomfort, difficulty breathing, stomachache, purple spots or patches on the skin, itching after bathing in warm water, headache, vision problems, nosebleeds, bleeding of the gums, bleeding of the stomach (which may be indicated by blood in the stools), and throbbing and burning pain in the skin.

complications

Chronic myelogenous leukemia (CML): Some people with CML produce too many platelets. Without treatment, this high platelet count (thrombocytosis) may cause excessive clotting of the blood, which may lead to a heart attack or stroke.
Some people with CML may have a shortage of platelet cells. This may result in easy bleeding and bruising, including frequent or severe nosebleeds, bleeding from the gums, or tiny red marks caused by bleeding into the skin (called petechiae).
Normally, white blood cells help fight against diseases and infections. In people with CML, the white blood cells of someone with CML are unable to function properly. Over time, the white blood cells overcrowd healthy blood cells. Eventually, the bone marrow may become damaged and stop producing white blood cells normally. All of these factors lead to an increased risk of excessive bleeding and developing infections.
CML can cause bone pain or joint pain as the bone marrow expands when excess white blood cells accumulate.
Some of the extra blood cells produced in people with CML are stored in the spleen. As a result, the spleen becomes enlarged, causing a feeling of fullness in the abdomen. If the spleen becomes large enough, there is a risk that it might burst. If the spleen breaks open, urgent medical surgery is needed. Without treatment, a ruptured spleen may cause life-threatening bleeding into the abdominal cavity.
Essential thrombocytosis: Individuals with essential thrombocytosis typically have high levels of platelets in their blood. If the blood clots too much, it may lead to a heart attack or stroke.
Myelofibrosis: Patients with myelofibrosis have an increased risk of bleeding. They are also more susceptible to developing infections than healthy individuals. In addition, patients have an increased risk of developing an enlarged spleen. In extreme cases, the spleen may rupture.
Polycythemia vera: Because individuals with polycythemia vera have thicker blood than normal, they have an increased risk of developing blood clots. A blood clot prevents blood from flowing normally throughout the body. A blood clot can be fatal if it blocks blood flow to a vital organ, such as the brain, heart, or lungs.
Patients have an increased risk of developing an enlarged spleen. In extreme cases, the spleen may rupture.