A large jar sits inside a white refrigerator in the pharmacy at Mercy Springfield. Inside that jar are what are classified as medical devices by the US Food and Drug Administration: about 20 medical grade leeches that are kept in case they’re needed, which is usually once or twice a year.
The rather colorful brown, yellow and orange parasites can go for a year without eating—they can’t eat or they wouldn’t be hungry for blood if the need to use them on a patient arises. They’re kept at about 43 degrees and don’t expend much energy—thus the lack of need to eat for such long periods of time.
Mercy pharmacist Terry Barks says they’re used primarily in microsurgery—things like limb reattachments and plastic surgery.
"The reason they're useful is that in those situations it's easy enough to reestablish the arterial blood supply to the reattached appendage or what have you, but the venous blood vessels are by comparison very small, thin vessels and it's hard to knit those back together," he said.
The vessels eventually grow back together, but the process can take several days. In the interim, according to Barks, blood tends to pool in those areas, which causes pressure and impairs the flow of new blood into that area.
"And sets the stage for clot formation and things which could jeopardize the healing of the reattached finger or whatever," he said.
He says leech saliva contains an anticoagulant, to which their therapeutic affect can be attributed. But the saliva also contains proteins including an anesthetic agent. That’s a good thing since leeches’ mouths contain three sharp blades. They feed for only about 20 minutes during which time they take in about a tablespoon of blood and then drop off. A single procedure uses from one to six leeches.
To thank them for their efforts, they’re dropped into a solution of 70% alcohol and placed in a sharps container. Reusing them would be like reusing a hypodermic needle.
According to Barks, leeches are never a first line choice—they’re used when first line options have failed.
The practice of using leeches in medicine goes back to the Ancient Egyptians, he says, when they would be used for virtually everything.
"Any ailments that entailed swelling and redness was considered to be due to an imbalance in one of the four humors of which there's blood, phlegm, black bile, yellow bile, and so anything that involved redness or inflammation was considered to be an excess of blood, and so they would blood let whether it be by leeches or some other mechanism," he said.
They were thought then to be a cure-all. Today they’re used much more discriminately.
Barks’ co-worker, fellow pharmacist Jackie Watkins, says the modern use of leeches goes back to around the mid 1980s. Mercy Springfield started using the parasites eight to ten years ago.
The leeches used at Mercy originate from Europe, and they’re ordered from a supplier in New York at a cost of about $10 each.
"We get them in overnight by air and change out their water immediately and get them set up in their leech locker that we have out in our inventory garage area," she said.
Wild leeches are never used for medical procedures since they can carry disease. The feeding habits of the leeches ordered from the supplier in New York are known and they’re raised in a clean environment. Mercy has used then in limb reattachments and in plastic surgery procedures.
Watkins says there can be a significant psychological side to leech therapy so patient acceptance and family acceptance are major considerations.