Maybe you’ve wandered the floors of an art gallery in the past, cringing at some of the medicinal practices depicted in paintings from the Medieval era: patients covered in leeches, drinking or eating questionable-looking substances, and being subjected to intentional head wounds or casual amputations. If so, you’ve likely also come across art showing the historical practice of bloodletting, when doctors would use a fleam or a lancet to open up a patient’s vein (usually the arm) and allow an unspecified amount of blood to drain into an empty vessel.
If this sounds awfully dangerous and unscientific, that’s because it was—and after hitting a peak of popularity in the 18th century, doctors began strongly discouraging the use of bloodletting to cure patients, noting that even in the best case scenario there weren’t any real bloodletting benefits (and could cause serious harm in the worst).
But that doesn’t mean those early doctors in the Middle Ages were completely off base; sometimes, removing blood from the body can be helpful, at least when done in a safe, controlled, and standardized way. It’s called therapeutic phlebotomy, and it has about as much in common with historical bloodletting as lobotomies do with advanced neurosurgery. Here’s how this practice has evolved over the years, how it’s done, and who it benefits.
What is bloodletting?
The first thing you need to know about the history of bloodletting is that its origins go way, way back. Some ancient Egyptian texts reference the practice. In Western medicine, it dates back to 5th century Greece, when Hippocrates (of the Hippocratic oath) theorized that our bodies were made up of four humors: blood, phlegm, black bile, and yellow bile. If one or more of these humors were out of balance with the rest, Hippocrates claimed, it could cause a host of common ailments and illnesses.
From there, early doctors adopted the practice of bloodletting, or removing blood from the body, as a treatment for an imbalance of humors. The well-known ancient Greek physician, Galen of Pergamum, became a major proponent of the practice. Bloodletting was often used for treating symptoms like fevers, headaches, hypertension, gout, nosebleeds, yellow fever, and smallpox, among others. George Washington, famously, underwent five bloodlettings in less than one day in an attempt to cure him from the illness that ultimately killed him.
So…was bloodletting effective? Certainly, the physicians performing it thought it to be an effective way of purging excess humors. But, the real-world evidence in the early 19th century showed a different picture. A small study performed in 1836 by French physician Pierre Louis examined the effectiveness of bloodletting in patients with pneumonia; the rate of improvement before and after bloodletting in these patients wasn’t significant, and Louis recommended bloodletting only be used for certain conditions—not as a widespread treatment.
Modern doctors believe that, in countless cases, bloodletting was not only unhelpful but contributed to the death of the same patients.
When did bloodletting stop?
Eventually, the four humors theory was debunked entirely in the mid- to late-1800s. Doctors and scientists in Europe, like John Snow (who figured out that cholera was spreading through contaminated water in London) and microbiology pioneer Louis Pasteur, began promoting the germ theory of medicine. That is, the idea that microorganisms cause disease, not an imbalance of humors.
As the humors fell out of favor, so did bloodletting; in the early 1900s, doctors began moving away from the practice, opting for blood transfusion over bloodletting in the 1920s, and by the late 20th century, it was mostly eliminated as a legitimate medical treatment.
Bloodletting versus therapeutic phlebotomy
Credible doctors may not be running around recommending bloodletting or leech therapy anymore, but that doesn’t mean there is no current medical practice borrowing some of its methodologies (although the modern implementation is much more sophisticated!).
Known as therapeutic phlebotomy, the procedure is essentially a blood draw, similar to a blood donation. Performed in a medical setting—such as a doctor’s office, hospital, or blood donation center—under careful observation, patients have a specific amount of blood drawn from their body at predetermined intervals ranging from once a week to once every few months, as needed. In some cases, blood drawn during therapeutic phlebotomy can be donated if the patient meets all other blood donation criteria.
“Therapeutic phlebotomy is done through a large IV placed by a nurse,” says medical oncologist Sandy Kotiah, MD, director of The Neuroendocrine Tumor Center at Mercy Medical Center in Baltimore. “We usually draw 500 milliliters of blood at a time, less if a person can’t tolerate a full phlebotomy or is anemic.”
Why is therapeutic phlebotomy done? There are primarily only two medical conditions that rely on it as a treatment: polycythemia vera and hemochromatosis. It may also be used to treat the rare skin condition porphyria cutanea tarda and increases of iron related to sickle cell anemia transfusions.
Polycythemia vera
Polycythemia vera is a rare blood condition that causes your body to make more red blood cells than you need. This is problematic, Dr. Kotiah says, because blood that’s too thick with excess red blood cells impedes proper blood flow. It could turn into a blood clot that causes a stroke, heart attack, or embolism.
Johns Hopkins Medicine reports that polycythemia vera happens as a result of a genetic change in the body as you age. Common symptoms of this condition include shortness of breath, fatigue, and dizziness. It occurs because your blood has become too thick to pick up oxygen, says University of Missouri Health Care hematologist and oncologist Cherian Verghese, MD.
Hemochromatosis
People with hemochromatosis store too much iron in their bodies, often ending up with toxic amounts of iron in vital organs like the heart, liver, and pancreas. If left untreated, these excessively high levels of iron can lead to cirrhosis of the liver, impotence, diabetes, liver failure, and heart problems, among other conditions over time.
Hemochromatosis is usually hereditary, passed down through parental genes, but can also be caused by repeated blood transfusions. Phlebotomy is a standard therapy for hemochromatosis. Part of your treatment plan can also be managed through diet and avoidance of iron-containing vitamins or supplements. In some cases, therapeutic phlebotomy may temporarily be discontinued, such as during pregnancy when iron levels often normalize.
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3 therapeutic phlebotomy benefits
If you’re still associating therapeutic phlebotomy with Medieval bloodletting, it’s time to move on. Today’s therapeutic phlebotomy is not only strictly regulated and standardized, it’s a safe and highly effective treatment for people who have too many red blood cells or too much iron in their blood.
Here are the benefits of therapeutic phlebotomy to treat polycythemia vera and hemochromatosis.
1. It’s safe
According to Dr. Verghese, the only risks involved with therapeutic phlebotomy are localized; in other words, you could experience pain, bleeding, or mild inflammation from the IV placement, but there are no systemic complications.
Dr. Kotiah agrees that therapeutic phlebotomy is largely safe—and that the biggest hurdle is often people’s fears of having blood drawn. “It’s really well tolerated, although some people will have a vasovagal response causing lightheadedness or fainting, and if you draw too much blood, they could feel tired,” Dr. Kotiah says. “But there are no long-term consequences—it’s really more annoying [to show up for regular phlebotomy] than anything else.”
2. It works well
Therapeutic phlebotomy is an effective treatment for these two blood conditions, though it can be slow-going at first; while hemoglobin levels will start dropping quickly, says Dr. Verghese, it can take a long time to get to your ultimate goal depending on how severe your condition is.
It may be worth it, though: A 2016 review in the Journal of Blood Medicine suggests that phlebotomy can decrease the rates of cardiac death and blood clots in patients with polycythemia vera, as well as reduce iron levels in tissue and improve survival rates for patients with hemochromatosis.
3. It can be used alongside other treatments
Some patients will need to take medication that also removes excess iron and red blood cells from the blood. It’s safe to do this in conjunction with therapeutic phlebotomy as long as your blood count is being regularly and carefully monitored.
If your labs normalize with just using therapeutic phlebotomy that’s an ideal scenario: “Medication treatments are less effective and more expensive, plus you get side effects,” Dr. Verghese explains. “Therapeutic phlebotomy is effective, cheap, and has little side effects.”
Common medications used to treat polycythemia include Hydrea (hydroxyurea). Medications are typically not prescribed for hemochromatosis unless a person can’t tolerate phlebotomy, or the condition has been caused by blood transfusions instead of genetics.
Therapeutic phlebotomy side effects
Again, therapeutic phlebotomy is relatively safe for most people—the biggest concern is localized pain and bleeding, or adverse reactions to blood draws such as fainting or dizziness. Rather than focus on side effects, per se, there are some potential pitfalls or drawbacks to this type of treatment.
1. It requires a delicate balance
In order to perform therapeutic phlebotomy safely, in a way that doesn’t overly deplete your iron or blood cell count, you’ll have to get frequent blood work so your healthcare provider can determine the right amount of blood loss. The optimal schedule for bloodletting has not been established, and the frequency can be tailored to the patient’s clinical status and hemoglobin level.
“With polycythemia vera, you want iron levels to be low only to a certain point,” says Dr. Verghese, “so if you have high red blood counts but your iron is too low, then therapeutic phlebotomy isn’t useful and you have to switch to medication.”
Both doctors also talked about the effort involved with getting a hemochromatosis patient’s blood levels right; because iron is stored by a blood protein called ferritin, lowering ferritin levels (not just iron levels) is actually key to treating patients with hemochromatosis.
“We like to get ferritin levels lower than what most people can tolerate,” Dr. Verghese says. “So where most people are at 500 [micrograms per liter] of ferritin, people with hemochromatosis may need to be as low as 50.”
2. It’s a commitment
There are no cures for polycythemia vera or hemochromatosis, but therapeutic phlebotomy can help people manage both of these conditions successfully, improving their overall health outcomes. Due to the chronic nature of these issues, you’ll need to commit to regular intervals of therapeutic phlebotomy for years to come.
“At first, we do therapeutic phlebotomy more frequently because we’re trying to get to our goal as quickly as possible,” says Dr. Kotiah. “Once we get to the right level, less phlebotomy is needed to keep your iron levels at goal—but it could take a year of going once per week before you can go down to once a month, or once every few months.”
For patients being treated with therapeutic phlebotomy it’s important to attend all their scheduled appointments and keep up with their blood work. Usually blood work is obtained every three months and at the time of each phlebotomy: “Staying on some sort of routine with phlebotomy will help you avoid more need for it,” Dr. Kotiah adds.
