Myeloproliferative neoplasms (MPNs) are a group of blood cancers characterized by the overproduction of blood cells in the bone marrow. These conditions are chronic and develop slowly over time. The bone marrow creates new blood cells from stem cells, but in MPNs, genetic changes cause these cells to produce an excessive number of red blood cells, white blood cells, or platelets. This overproduction can lead to a variety of health issues as the excess cells build up in the blood and bone marrow.
General Symptoms of Myeloproliferative Neoplasms
Many individuals with myeloproliferative neoplasms may not show any signs of the condition in the early stages and are often diagnosed after a routine blood test. When symptoms do appear, they are often generalized and can vary from person to person. One of the most common is fatigue that is not relieved by rest, which can be accompanied by weakness, unexplained weight loss, fever, and drenching night sweats.
Another frequent indicator is an enlarged spleen, a condition known as splenomegaly. The spleen, an organ located in the upper left of the abdomen, can become swollen as it filters the excess blood cells. This enlargement can cause a feeling of fullness after eating only a small amount of food, known as early satiety, as well as discomfort or pain in the abdomen.
Generalized itching, or pruritus, is a characteristic symptom of MPNs. This itching is often described as occurring all over the body and may be noticeably worse after a warm bath or shower. Bone pain can also occur, caused by the increased activity and crowding of cells within the bone marrow.
Symptoms Specific to the Type of MPN
Polycythemia Vera (PV)
Polycythemia vera is primarily defined by the overproduction of red blood cells, which makes the blood thicker and slows its flow. This increased blood volume and thickness, called hyperviscosity, can lead to frequent headaches, dizziness, and blurred or double vision. Some people may develop a reddish complexion, particularly on the face, due to the high concentration of red cells. A symptom of PV is severe itching, especially after exposure to warm water, a phenomenon known as aquagenic pruritus. The condition also elevates the risk of blood clots.
Essential Thrombocythemia (ET)
In essential thrombocythemia, the bone marrow produces too many platelets. This can paradoxically lead to both blood clotting and bleeding problems. The high number of platelets can cause them to stick together, forming clots (thrombosis) that can block blood flow in vessels. Symptoms of a clot can include pain and swelling in a limb, sudden shortness of breath, or neurological changes. Conversely, the platelets may not function correctly, resulting in easy bruising, nosebleeds, or other bleeding events. A specific symptom associated with ET is erythromelalgia, a burning pain and redness in the hands and feet.
Myelofibrosis (MF)
Myelofibrosis is distinguished by the development of scar tissue, or fibrosis, within the bone marrow. This scarring disrupts the normal production of blood cells. Fatigue is often severe. As the bone marrow becomes less able to produce blood cells, other organs like the spleen and liver take over this function, causing them to become significantly enlarged and leading to abdominal pain and fullness. The scarring also results in low counts of normal blood cells, particularly red blood cells, which causes anemia and its associated weakness and shortness of breath. Bone pain can be especially intense in MF.
How Blood Cell Counts Influence Symptoms
The specific symptoms experienced by individuals with an MPN are directly linked to which type of blood cell is being overproduced. The number and function of these cells alter the blood’s properties and how it interacts with the body’s systems. This connection explains why different MPNs have distinct clinical presentations.
Myelofibrosis presents a more complex picture. The scarring of the bone marrow impairs its ability to produce any type of healthy blood cell. As blood cell production moves to other organs, mainly the spleen, it causes significant enlargement and associated pain. The failure of the bone marrow leads to shortages of normal cells, resulting in anemia (low red blood cells) causing fatigue, leukopenia (low white blood cells) increasing infection risk, and thrombocytopenia (low platelets) causing bleeding.
Seeking a Medical Diagnosis
The symptoms associated with myeloproliferative neoplasms can also be caused by many other health conditions. For this reason, experiencing one or more of these signs does not automatically point to an MPN. It is important to consult a healthcare provider for any persistent or worrying symptoms for an accurate diagnosis.
During a medical evaluation, a doctor will likely begin by taking a detailed medical history and asking about specific symptoms, such as fatigue, night sweats, or itching. This will be followed by a physical examination, where the doctor may check for an enlarged spleen or liver by gently feeling the abdomen.
The next step involves blood tests. A complete blood count (CBC) is a standard test that measures the levels of red blood cells, white blood cells, and platelets in the blood. Abnormalities in these counts can be the first clue to an underlying MPN. If an MPN is suspected based on these initial findings, further specialized tests, such as genetic testing for specific mutations like JAK2 and a bone marrow biopsy, may be recommended to confirm the diagnosis.