Wednesday, November 26, 2003

High red blood cell count can have consequences

By ALLEN DOUMA, M.D.
Tribune Media Services

Q. A couple of my friends have anemia and I’ve learned a lot about it through them. But I was recently told that I have a condition called polycythemia, which means I have too much blood. The doctor also said I will need to have blood drawn regularly. Will I grow out of this or is there any treatment besides having blood drawn?

A. Your friends have one of the most common medical problems. As you have learned, someone with anemia has too few red blood cells. And many people have abnormal red blood cells. But a few people, like yourself, have too many.

Red blood cells are produced in the bone marrow. And polycythemia vera is a blood disorder in which the bone marrow produces too many blood cells, especially red blood cells. The red cells are normal; there’s just too many of them.

The average age at which polycythemia vera is diagnosed is about 55, but it can develop as early as age 40. An equal number of men and women are affected.

The excess number of cells in the bloodstream lowers the amount of liquid in your blood vessels. This makes the blood more viscous (thicker), so it flows less easily, especially through smaller blood vessels.

Many symptoms of polycythemia vera relate to the increased viscosity. Common complaints include headache, dizziness, noises in the ear, blurred vision and fatigue. In most cases, the spleen is enlarged because of the increased number of cells being recycled there.

Polycythemia vera is suspected when a routine blood test shows the hematocrit — the percentage of red cells in the total blood volume — is elevated. But diagnosis is not based on hematocrit alone. A blood test to estimate the total number of red cells in the blood is needed to confirm the diagnosis.

Two similar disorders can cause an increased hematocrit. One, polycythemia, occurs when the number of red cells is normal but the liquid part of the blood is decreased.

Secondary polycythemia is a disorder that occurs when the bone marrow produces more red blood cells to make up for low levels of oxygen in the blood. This can occur with smoking, lung and heart disease, or living at high altitudes.

The most serious complication, and cause of most illness and death from polycythemia vera, is the danger of blood clotting (thrombosis) in the arteries, both large and small. Also, about 5 percent of people with this condition will get a form of acute leukemia that is very hard to treat.

Secondary polycythemia canbe improved with removal or treatment of the cause of low oxygen. But there is no cure for polycythemia vera.

The treatment of choice is phlebotomy; in which whole blood is removed in the same way blood is donated. As you would expect, this blood cannot be used for transfusions. Phlebotomy usually begins at the rate of a pint every week, and then tapers off as blood cell counts gradually return to normal.

Drug treatment to suppress production of blood cells, especially platelets that clot the blood, is worth considering. But this form of treatment has had mixed success and not many of the drugs are recommended for long-term use. The anticancer drugs hydroxyurea, busulfan and alpha interferon have been shown to control the disorder in some cases.

To decrease the risk of blood clots, even with a higher number of platelets, you may want to try aspirin or dipyridamole, but this needs to be balanced against the increased risk of bleeding.

I’m sorry to report that under the treatments known today, most people will not live more than 15 years after they are diagnosed with polycythemia vera. You need to verify whether you have polycythemia vera or another type. Once that’s done, regardless of the type you have, make sure you are adhering strictly to your treatment plan.