Polycythemia

Polycythemia is a blood disorder occurring when there are too many red blood cells, which carry oxygen from the lungs through the blood stream to the rest of the body. The excess red blood cells cause the blood to increase in volume and thicken, keeping it from flowing easily.

Polycythemia can be divided into two overarching categories:

• Primary polycythemia, caused by overproduction of red blood cells by the bone marrow due to mutation or biological factor in the body.
• Secondary polycythemia, which is caused by factors that reduce the amount of oxygen reaching the body’s tissues, such as smoking, high altitude or congenital heart disease. The red blood cells in some patients with secondary polycythemia may carry an abnormal form of hemoglobin that does not release oxygen readily (high-affinity hemoglobin).

There are three forms of primary polycythemia:

• polycythemia vera or primary bone marrow polycythemia, an adult disease of the blood-forming hematopoietic stem cells
• primary familial and congenital polycythemia, caused by genetic abnormalities or inappropriate levels of a hormone called erythropoietin (which triggers red blood cell production)
• newborn polycythemia, which is detected before or at birth and treated in a neonatal intensive care unit

The Blood Disorders Center at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center specializes in the treatment of children with primary familial and congenital polycythemia.

Infants and children with polycythemia often have no visible symptoms. When they do appear, the most common symptoms include:

• deep reddish-purple coloring
• poor feeding
• tiredness or fatigue
• shortness of breath or breathing difficulty
• low blood sugar
• headache
• dizziness
• itchiness, especially following a warm bath or shower
• numbness, tingling, burning or weakness in your hands, feet, arms or legs

In addition to a complete medical history and physical examination, diagnostic procedures for polycythemia may include:

• high red blood cell counts or hemoglobin levels
• genetic tests to determine what is causing increased red blood cell production

After all tests are completed, doctors will be able to outline the best treatment options.

Treatments for polycythemia can include:

• phlebotomy (withdrawal of blood through the veins)
• medication such as hydroxyurea to reduce blood cells
• low-dose aspirin

With secondary polycythemia, treatment usually focuses on the underlying cause.

New medications for adult polycythemia vera are currently in development. The results of these efforts, as well as of studies of the biology of adult polycythemia vera, may one day benefit children with other forms of polycythemia.

The prognosis for children with polycythemia depends on the form of the disease and how well it responds to treatment, but it is quite possible to reduce a child’s red blood cell count to a safe number.