Myelofibrosis

By Michael Ramsey
Medical Editor

Reviewed by Bernard Abrams, MD
Medical Director

Myelofibrosis is a form of leukemia affecting bone marrow, and is most common in people over the age of 50. As the condition progresses, pain levels intensify. Since a cure is generally unlikely, pain management becomes a major concern.

Etiology

Collagen builds up fibrous scar tissue inside the marrow cavity. This is caused by the uncontrolled growth of a blood cell precursor, which results in the accumulation of scar tissue in bone marrow. The condition gradually changes bone marrow tissue into scar tissue, thus inhibiting the bone marrow’s ability to create new blood cells.

As a result of myelofibrosis, other organs in the body, particularly the spleen and liver, may become enlarged in an attempt to provide the body with the necessary blood cells. In some cases, the spleen becomes so enlarged it is necessary to remove it, so that the patient experiences less pain. Some people with myelofibrosis eventually develop acute myelogenous leukemia, a type of blood and bone marrow cancer that progresses rapidly.

Symptoms

Symptoms of myelofibrosis include low platelet count, anemia, and an enlarged spleen. Those effected may also feel uncomfortable fullness or pressure in the stomach, note more significant bleeding or bruising after slight injuries, exhibit paleness, feel fatigued, and get sick more easily and more often.

In some patients the condition may result in only minor symptoms, but in general, the final stages of myelofibrosis are painful and difficult. Patients may spend a long time in the final stages of myelofibrosis creating difficult to manage situations for them and their support groups.

Complications

Patients may experience any or any combination of these complications associated with myelofibrosis:

• Inflammation - Episodes of inflammation or tissue death in the spleen can lead to pain in the upper left side or shoulder region.
• Other organ involvement -  Formation of blood cells outside the bone marrow (extramedullary hematopoiesis) may create clumps (tumors) of developing blood cells in other areas of the body. These tumors may cause problems such as bleeding in the gastrointestinal system, coughing or spitting up of blood, spinal cord compression, or seizures. Extramedullary blood formation is usually treated with low-dose radiation.
• Infection - Myelofibrosis may cause the overproduction of white blood cells, which help fight infection. But in myelofibrosis, these blood cells often aren't fully formed or are mutated so that they become ineffective, actually decreasing the ability to fight off infection.
• Bleeding complications - As the disease progresses, platelet count tends to drop below normal (thrombocytopenia) and platelet function becomes impaired. An insufficient number of platelets may lead to easy bleeding.
• Hardening and inflammation of bone tissue -Myelofibrosis can lead to bone marrow hardening as well as inflammation of the connective tissue surrounding the bones, resulting in tenderness and severe bone and joint pain.
• Gout - Myelofibrosis increases the body's production of uric acid, a byproduct of the breakdown of purines — a substance found naturally in the body and in many foods. Overproduction of uric acid can lead to needle-like deposits of the substance in joints, causing joint pain and inflammation (gout). Medications may be required to normalize and maintain uric acid levels.

Diagnosis

A complete blood count test and a physical examination of the spleen usually can make physicians suspect myelofibrosis. They may confirm their suspicions by sampling bone marrow to evaluate its quality.

Treatment

Currently, the only treatment available is bone marrow transplant, and due to limited availability of suitable donors, difficulty of the procedure, and post procedure chemotherapy, most afflicted persons (those over 50) are considered poor candidates for surviving treatment.

On rare occasions, children develop myelofibrosis, and in these cases, bone marrow transplant is the preferred treatment as it may stop the course of the illness and extend life. Even with bone marrow transplant, the outlook for myelofibrosis is not favorable. The disease may recur, requiring another transplant.

Prognosis

The condition may progress very slowly in the elderly, and many live for years with the condition, though the average survival rate after diagnosis is five years.

Developments

Currently, Incyte Pharmaceuticles is testing the first ever drug therapy for this condition. Details will follow.

Alternative Names

Myelofibrosis goes by many names including idiopathic myelofibrosis, agnogenic myeloid metaplasia, chronic myelosclerosis, aleukemic megakaryocytic myelosis, and leukoerythroblastosis.