Myelofibrosis is a bone marrow disorder that is part of a group of conditions called myeloproliferative neoplasms (MPNs). It results in the abnormal development and function of blood cells, scarring the bone marrow and increasing the risk of other health complications. The condition may be of two types – primary myelofibrosis, when it is caused by genetic mutations, or secondary myelofibrosis, when it occurs as a result of other blood-related disorders.

Symptoms
Many individuals do not experience symptoms at the onset of the condition. As myelofibrosis progresses, its symptoms may start to appear slowly. These most commonly include fatigue or extreme tiredness, shortness of breath, night sweats, unexplained fevers, itching, and general weakness.

Some people with myelofibrosis may also experience bone pain. While it may occur at any stage of the condition, it is typically reported when scarring and inflammation appear in the bone marrow.

Other symptoms may vary depending on one’s blood count.

Symptoms due to high blood counts
In the prefibrotic stage of myelofibrosis, one may develop high levels of white blood cells (WBCs) or platelets. This can increase one’s risk of blood clots around the body. Symptoms here would differ depending on where the clot develops but may include slurred speech, weakness on one side of the body, drooping of one side of the face, sudden chest pain, shortness of breath, coughing up blood, sudden blurred vision or loss of sight, pain in the stomach area, and signs of jaundice. High blood counts due to myelofibrosis may also increase the risk of a hemorrhage or unusual bleeding.

Symptoms that arise due to low blood counts
As blood counts begin to drop, one may experience a different set of symptoms. A drop in the red blood cell (RBC) count may make one feel tired, breathless, or dizzy as a result of anemia. Moreover, decreasing WBCs can make individuals more susceptible to infections, increasing the frequency and intensity of common conditions such as cold and flu. When platelets drop, individuals may be at higher risk of bruising easily and unusual bleeding.

If the bone marrow cannot produce enough blood cells, the spleen may need to work overtime, giving rise to pain or discomfort around the stomach, loss of appetite or feeling full quickly, and/or vomiting.

Causes
While the underlying cause of myelofibrosis remains unknown, in most cases, it occurs as a result of genetic mutations in the bone marrow stem cells. The stem cells hold the ability to replicate and multiply, taking up various roles in the body in the form of red and white blood cells and platelets. When the mutated cells multiply, they pass the abnormalities to newer cells. This increase in mutated cells hampers healthy cell growth, leading to the progression of the disease. Several gene mutations have also been associated with this condition.