 |
Thomas S. May, M.A.Medical Writer |
|
|---|---|---|
|
|
Polycythemia Vera: A Rare Disorder that calls for an Unusual Treatment
By Thomas S. May, Medical Writer
Phlebotomy or bloodletting was the mainstay of medicine for over a thousand years. "The art of bloodletting was flourishing well before Hippocrates in the fifth century B.C.," according to Graham Ford of the Museum of Questionable Medical Devices in Minneapolis, Minnesota.
By the middle ages, both surgeons and barbers would treat their patients for almost any disorder by opening their veins "to reduce the negative forces" contained in their blood. "The practice reached unbelievable heights in the 18th and early 19th centuries. The draining of one to four pints of blood was typical. Blood was often caught in a shallow bowl, and when the patient became faint, the 'treatment' was stopped," Ford explains.
By the end of the 19th century, phlebotomy was declared quackery, and today it is only used to treat a very small number of diseases. One of the few medical conditions where phlebotomy is still routinely used is Polycythemia Vera, a relatively rare blood disorder that strikes approximately one in 100,000 people each year.
Too much of a Good Thing
Polycythemia Vera (PV) is one of the so-called "myeloproliferative diseases," which are marked by the excessive growth of cells produced by the bone marrow. Patients with PV have an increased number of red blood cells, and this results in a number of unique symptoms and complications.
Having a lot of red blood cells is, in general, considered a good thing. Red blood cells carry oxygen from the lungs through the entire body, and they are vitally important for everyday activities. In fact, it would be impossible to survive without them.
Some athletes even take drugs to increase the production of red blood cells, in an attempt to enhance oxygen transport, which can, in turn, improve aerobic power and endurance during training and competition. Nevertheless, it is possible to have too much of a good thing when it comes to red blood cells, as evidenced by the thousands of patients who are suffering from PV.
Fighting Fire with Fire
One of the most serious consequences of this disease is that patients are at a high risk of bleeding. Excessive bleeding may occur, for example, after a relatively minor injury or surgical procedure. Patients with PV may bruise very easily, or they may suffer from frequent nosebleeds or bleeding gums. Other, more serious bleeding problems may include having blood in the stool, coughing up blood, or excessive menstrual bleeding in the case of women.
This may seem paradoxical, since bleeding is one of the main problems associated with PV, but currently the only effective initial treatment for this disease is phlebotomy or the removal of blood. Often, three to four liters (six to eight pints) are withdrawn during the first two or three weeks to reduce the circulating red blood cell volume to normal.
After the number of red blood cells has been brought under control, periodic phlebotomies are required to maintain the red cell mass within the normal range and to induce a state of iron deficiency, which serves to prevent the overproduction of red blood cells. Once an iron-deficient state is achieved, phlebotomy is usually required only once every two or three months for most patients.
Other Treatment Options
Although necessary in most cases, phlebotomy is not the only treatment method for Polycythemia Vera. Other possible treatment options include the administration of drugs such as Hydroxyurea or Interferon, and--in some cases--bone marrow transplant and/or removal of the spleen.
According to some recent research, Interferon may be superior to phlebotomy and may become the treatment of choice for severe cases of PV in the future. Not all doctors agree with this assessment, however.
In some cases, another drug called Hydroxyurea may be indicated for patients suffering from PV. "Hydroxyurea is given only to patients who have already had serious complications such as a heart attack or stroke," says Klaus Lechner, MD, a professor at the University of Vienna, Austria. "Although there is some suspicion that Hydroxyurea may be associated with a higher incidence of Leukemia, currently there is no scientific evidence to show that this is, in fact, the case," Dr. Lechner explains.
An Aspirin a Day?
Because increased blood viscosity or thickness is one of the distinguishing features of PV, many people believe that regular, low-dose Aspirin treatment may prevent complications such as heart attacks or strokes. Dr. Lechner is not convinced, however. "There is no evidence for the efficacy of daily, low-dose Aspirin for PV. Still, I think that most patients do take low-dose Aspirin regularly, even though there is no evidence of its efficacy. There is a clinical trial going on currently in Europe to evaluate the efficacy of low-dose Aspirin. We'll know the results of this study in about four or five years," Dr. Lechner says.
Prompt Diagnosis is Crucial
Ruddy cheeks are among the telltale signs of PV, but the high color is often misread as a sign of robust health or attributed to exposure to the elements. This is very unfortunate, because prompt diagnosis and treatment are crucial for patients suffering from this disease.
According to some studies, more than half of all untreated patients die within 18 months of diagnosis. In contrast to these data, there is also evidence that many patients with PV have a normal life expectancy when the disorder is properly diagnosed and treated.
Sidebar:
Common Symptoms of Polycythemia Vera
(From "Polycythemia Vera and Other Myeloproliferative Diseases" by Jerry L. Spivak, in Harrison's Principles of Internal Medicine, McGraw-Hill, 1999.)
|