Myelofibrosis is a rare blood cancer that originates in the bone marrow. The disorder is characterized by disruption in production of normal blood cells. The disease causes fibrous scarring in bone marrow, which further leads to anemia, fatigue, and spleen enlargement. Myelofibrosis is a type of chronic leukemia. It can develop as a primary disease or as a consequence of another bone marrow disease.
Myelofibrosis belongs to a group of blood cancer called as myeloproliferative neoplasms (MPN). The disease has chronic and disabling course which worsens with progression eventually leading to more serious leukemia.Some people live symptom free for years.
Myelofibrosis occurs due to genetic mutation in the blood stem cells. Treatment is aimed at relieving symptoms and to reduce complications if present. Treatment consists of blood transfusion, radiation, chemotherapy, medicines to treat anemia and transplantation of stem cells.
Signs And Symptoms Of Myelofibrosis
Myelofibrosis is a slow and progressive disease. In its initial stage people may not develop any symptoms. Almost one third patients are asymptomatic. But as the interruption in production of normal blood cell increases patient may start experiencing symptoms.
These symptoms include:
- Fatigue and weakness mainly caused due to anemia.
- Recurrent infection because of low white blood cells count.
- Pain under the ribs on left side due to spleen enlargement.
- Easy bruising and bleeding due to low platelet count.
- Excessive sweating during sleep.
- Unexplained loss of weight.
- Liver enlargement
- Skin pallor.
- Pain in bones
- Sweating at night
Causes And Risk Factors Of Myelofibrosis
Myelofibrosis is a rare form of blood cancer. In United Sates approximately 1 in 100000 people suffer from myelofibrosis in a year. The disease can affect both men as well as women. It occurs usually in people over the age of 50 years, but it can also affect young people. Normally the blood stem cells can multiply into various cells such as red blood cells, platelets and white blood cells.
The onset of disease takes place when there is genetic mutation in the blood stem cells. The exact cause of gene mutation is not known. One important feature of myelofibrosis is production of excessive megakaryocytes. They are called giant cells in the bone marrow. They get fragmented into thousands of platelets. With excess of platelets a chemical called cytokines is released in bone marrow.
Cytokines is responsible for formation of fibrous tissue in the bone marrow. Because of fibrous tissue the bone marrow becomes scarred and damaged otherwise normal bone marrow is soft and spongy. In some people mutation is found in Janus Kinase 2 (JAK2) gene.
Risk factors for development of myelofibrosis include:
- Exposure to ionizing radiation.
- Exposure to petrochemicals such as benzene and toluene.
- Patient suffering from another myeloproleferative disorder such as polycythemia or thrombocythemia.
Complications Of Myelofibrosis
Complications occur as the disease progresses.
- Increased blood flow from spleen to liver leads to portal hypertension. High blood pressure in portal vein can cause bleeding in smaller veins of esophagus and stomach.
- Severe pain in left side of abdomen and back due to abnormal enlargement of spleen.
- Severe pain in bones due to hardening of bone marrow and inflammation around the connective tissue surrounding the bones.
- Myelofibrosis can increase production of uric acid in the body. Excess of uric acid can settle in joints forming uric acid crystals. These crystals lead to gout a painful condition of joints.
- In 10 to 12 percent patients may suffer from acute myeloid leukemia.
Diagnosis And Treatment Of Myelofibrosis
Following tests are necessary for diagnosis of myelofibrosis.
- Physical examination to check enlargement of spleen and liver.
- Blood tests reveal abnormal low level of red cell count, increase in number of white cell count, increase in platelets.
- Abnormality in bone marrow biopsy can confirm the diagnosis.
- Ultrasound examination to determine the size of spleen and liver.
- MRI to know changes in bone marrow.
In some patient where symptoms are not present, the doctor may not start any treatment but monitor the patient from time to time for any progression. There are several patients who are free from any symptoms for years together and they live without any specific therapy.
However, when symptoms develop following treatment may be necessary to alleviate symptoms and reduce complications. This includes blood transfusion periodically in case of severe anemia. Chemotherapy and radiation is beneficial to reduce the size of spleen and reduce symptoms of severe pain in bones and other parts of body. In some cases surgical removal of spleen is a preferred choice.
Allogenic stem cell transplant from a donor has proved beneficial for many patients. It helps to cure the condition but it has serious side effects too, sometimes life threatening. Stem cell transplant depends on several factors such as age because most patients with myelofibrosis are old and they often suffer from other diseases as well. Hence they may have decreased tolerance for this therapy.