Polycythemia vera, also known as erythremia, is a rare disorder of the blood that is caused by overproduction of blood cells in the bone marrow. The red blood cells are most noticeably overproduced, but white blood cells and platelets are also usually in excess with this condition. As a result of the excess red blood cells, the blood becomes thicker. This can cause problems with blood flow through smaller blood vessels, leading to a variety of symptoms. It is not typically fatal if treated.
Erythremia is classified as a myeloproliferative disorder (MPD), along with three other diseases that overproduce either red, white, or platelet cells: essential thrombocythemia, chronic myeloid leukemia, and idiopathic myelofibrosis. Polycythemia vera, like the others in this category, can be considered a cancer of the blood. It occurs in approximately one in 100,000 people and is not age-discriminate, although some studies have suggested it occurs more after 60 years of age, and is more common in men than women.
Since erythremia develops slowly, there may be no symptoms present at first. Often, polycythemia vera is only detected when a blood test is done. If not diagnosed, symptoms such as headache, dizziness, and itching, especially after taking a warm bath, may occur. Other symptoms include fatigue, shortness of breath, difficulty breathing, and a bloated feeling in the left upper abdomen due to an enlarged spleen. Rarely, there can be a tingling, numbness, or burning feeling in the hands or feet. If left untreated, the thickening of the blood caused by polycythemia can lead to clots, which can lead to stroke and its associated symptoms.
There can be additional associated problems with polycythemia vera. Peptic ulcer disease seems to be common in those with the disease, although no one is sure why. Gouty arthritis appears in a fifth of all patients with polycythemia vera. Other issues caused by clotting of the blood, such as heart failure, can also occur.
The diagnosis for polycythemia vera is done primarily based on blood work and any visible symptoms. The blood is checked for increased counts of red blood cells, white blood cells, and platelets. It is also checked for a decreased erythrocyte sedimentation rate (ESR), which is the rate at which red blood cells coagulate. Patients are also checked for increased hemoglobin or hematocrit, the percentage of red blood cells in the blood. It has also been found that over 90% of people with polycythemia vera have a mutation of the gene known as JAK2, which may be helpful in diagnosing future cases when the blood work does not show increased hemoglobin or hematocrit.
Since polycythemia vera is considered incurable, the treatment consists of controlling the symptoms. Low dose aspirin is given to keep the blood thin and is often used in bloodletting, a process that gradually decreases the amount of blood. Chemotherapy can be administered, but can lead to acute myelogenous leukemia (AML), so many doctors prefer not to use chemotherapy treatment. Rarely, a bone marrow transplant is performed. As long as the symptoms are managed, there is often no risk of fatality.