In the first Bonus episode of Season 1, Evan talks with Dr. Kristen Dicks about contemporary medicinal uses of leeches.
After a brief introduction, Dr. Dicks shares some of her encounters with medicinal leeches (2:29) before diving into the history of leech therapy (5:26). They then discuss contemporary hiroudotherapy practices (9:19) and some of the ethical implications of leech harvesting (14:45), closing with Dr. Dicks's leechiest film (23:40).
Evan 00:30
Hey everyone, welcome back to the Leech Podcast. This is Evan Cate. And I have a very special episode today. We're joined by Dr. Kristen Dicks. But before we do that, I want to remind all our listeners that the Leech Podcast is a podcast about movies that suck the life out of you, but also stick with you. Usually in a good way, kind of like a leech. We realized that our knowledge of leeches was pretty limited as a team. And so we thought it'd be helpful to bring in an expert on leeches. So I'm very grateful and excited to talk today to Dr. Kristen Dicks, a friend of mine, who knows a lot about medicinal uses of leeches. Kristen, welcome to the show.
Kristen Dicks 01:16
Thank you. It is an honor to be here.
Evan 01:19
Yes, thank you for being with us. Can you tell us just a little bit about your background in medicine, and then with leeches?
Kristen Dicks 01:27
Absolutely. So I have trained in internal medicine, and then I specialized in infectious diseases in adults. So I see people who have been, or have suffered from infections, relative bacterial, viral fungal infections, kind of across the spectrum. And so I will clarify that I'm not an expert in leeches, but I am an expert in infections that can happen from leeches, or from leech therapy, specifically. And so that is kind of where I come into play. I have seen patients who have had infections related to leech therapy before. And as I started looking more into the medicinal leech therapy, I just found it's incredibly fascinating. So I'm really pleased to be able to be here and talk to you about it today.
Evan 02:11
Awesome. Well, thanks again. We look forward to hearing more about these medicinal purposes of leeches. [Absolutely.] Yeah. Something you just said that stands out is that you have a bunch of stories about leeches. So I wonder if you could start maybe with an encounter you had with a leech in medicine or reaction from a leech?
Kristen Dicks 02:29
Yeah. Yeah. So I'll, one that I came across is when I was a resident training at the Durham VA. There was a patient who had a skin graft performed. So he had a chronic wound, I think it was on his arm, and they had taken skin from a different part of his body and put it on that skin defect so that it would heal. And it wasn't taking, it wasn't healing correctly, the blood flow is pretty poor. And so they got the plastic surgeons involved, and the plastic surgeons helped prescribe the medical leech therapy. And so they brought a couple of leeches to place on the skin graft. And through the magic of leech therapy, which I'll talk about in a little bit, it helped reconnect these capillary connections and get the blood flow going. And the skin graft took and the patient did well.
Evan
That's unbelievable. [Remarkable.]
Kristen Dicks 03:20
Yeah. And I came across this other story that I thought was great. So this is back from 1985. This is kind of when medicinal leech therapy really started coming back around in the United States. And there was a five year old who had had his ear bitten off by a dog. [Oh, wow.] And so, obviously, they want to get that ear back reattached. And it's apparently extremely difficult to reattach an ear because there's all these micro capillary connections that are very hard to reconfigure. And so this child and his surgeon undergoes a 12 hour surgery to get the ear reattached. In the surgery, yeah, they get through the surgery, but then the healing process is complicated by poor circulation to the ear. And so they find that the ear is... there's blood flow kind of pooling in the reattached ear and it's looking bruised, and it's getting swollen. And they've tried a couple of different methods to get the ear to heal. So they tried cutting the skin around there to bleed out some of that blood. And that didn't really work. And then they tried a medication to give to him by vein to help deal with a clotting and that didn't work. So finally they brought in the leeches. And what they ended up doing is they put, I think, just a couple of leeches on for a couple of hours every day. And they ended up treating him for a week with leech therapy. And it took and it worked and he did great.
Evan 04:43
And his ear works and he's good?
Kristen Dicks 04:45
Yeah, reattached, look wonderful. I came I found a picture associated with this story. And it looks totally normal. There's a little bit of a scar behind the ear where you can tell the surgery was done. But other than that, you'd never know.
Evan 04:57
That's unbelievable. I... [Yeah.] Listeners can't see this, but my mouth is just like hanging open. I cannot believe what you're telling me. So a lot of questions come to mind based on these stories. But I thought I would start with just some history. You mentioned 1985 was a year that leech therapy kind of came back around in the United States. But I was wondering if you could tell us a little bit more, maybe some key moments in the history of medicinal leech therapy.
Kristen Dicks 05:26
Oh yeah, leech therapy goes way back. So leech therapy comes from this idea that bloodletting is important to keeping people healthy. It was thought, you know, back in the 18th century, that we had bad humors in our system that contributed to disease. And so, as a part of that, they would cut people and let them bleed out those bad humors. But of course, that's a painful process. No one's really excited about about getting lanced so that they can bleed out their evil humors. So then they discovered leech therapy, and it's a painless way to do bloodletting. And it's painless because leeches have this special saliva that secretes an anesthetic protein. And so when... Yeah, and that's why when, if anyone who's listening has ever been bitten by a leech, you usually don't realize it until later. Because when they attach, it's painless, because they have this anesthetic in their saliva. And then they also have another protein that serves as an anticoagulant, meaning it leads to bleeding, which is how the leech feeds off of you. And so this whole leech therapy came around because it is a painless process to do bloodletting.
Evan 06:36
A very natural process. it sounds like,. [Exactly, exactly.]
Kristen Dicks 06:39
So a doctor could prescribe this bloodletting therapy. And people could go out into the swamps and find their medicinal leeches and bring them back and sell them. And this actually turned into a huge business. And so much so that medicinal leeches were over harvested to the point of near extinction in many countries in Europe back in the 18th century. Yeah.
Evan 06:59
So are there still are there like, species of European leeches that are like on the endangered species list? Is that...
Kristen Dicks 07:05
There are some now that are protected. [Wow.] There's, yeah, there's a very specific niche of medicinal leeches.
Evan 07:12
Hold on, a, a leech niche, you would say?
Kristen Dicks 07:16
That's right. Yeah. And in certain countries, they're considered... I don't really think that they're near-extinct, but they are protected in one way or another. [Okay. Wow.] Yeah. So when leech therapy was discovered, and it hit big, it was popular. There's another story I came across about a French physician who believed that all disease stemmed from basically the same cause. And so he recommended leech therapy for every patient that came in, regardless of symptoms. And so as soon as someone came in, he prescribed 30 leeches for them for their troubles.
Evan 07:52
30. [30.] Just like placed anywhere on their body? or like.. [I guess.] Wow, yeah. So, I mean, that does lead to a practical question for me, which is, how many leeches? You know, depending -- I guess it depends on the procedure -- but what's the usual number of leeches needed per say, a skin graft or maybe per square inch of human flesh?
Kristen Dicks 08:15
Yeah, that's a great question. I guess it depends on the size of the defect that you're trying to address. But what I've come across is it's more like one or two or three leeches that attach and feed for anywhere from 30 to 90 minutes. They usually take in five milliliters to 15 milliliters of blood at a time. [Okay.] And once they're full, they -- what they say -- they auto-detach, they fall off. And so, part of leech therapy is making sure that when the leech auto-detaches, he doesn't auto-detach into the patient's gown or some other part of their body that's gonna freak them out.
Evan 08:51
Right, so if it auto-detached, and was not picked up, does, does the leech just absorb all that blood? Or would they like, expel it in some way? Like, what happens? [They process it in their stomach.] Do they bring waste? Like what happens to it? The blood?
Kristen Dicks 09:06
Oh, good question. They have bacteria that allow them to process all the blood in their stomach. And I don't know if it's absorbed or if they excrete it after that, that's a good question.
Evan 09:19
Okay, so -- sorry, to get back to this-- so walk me through the process itself. Sounds like you put the leeches on there. You let them do their job for 30 to 90 minutes. And then, I guess, what happens afterwards? Where are the leeches put? Who takes care of them? Do they have names? Like, what's what? Where do they live in the hospital?
Kristen Dicks 09:40
Right? Yeah, so, so yeah. How do you do leech therapy in the present day? So what I read that I think is really interesting is there's only a couple of places where you can get medicinal leeches now. I read that there's a company out of Wales that supplies most of these.
Evan 09:56
Okay. [I don't know] Did you catch the name of that company by chance? We're always looking for sponsors on the Leech Podcast.
Kristen Dicks 10:01
BioPharm. bio-ph-arm.
Evan 10:04
BioPharm. Alright, if you're listening, BioPharm, we would love to pitch a sponsorship deal. Sorry, sorry, Kristen.
Kristen Dicks 10:12
We're hawking your product. And as a side note, as I was looking through the internet doing some research about this, I found that there's all these other places you can order medicinal leeches. I don't know if they are legit medicinal leeches. So there may be more more options than that one. [Okay.] But anyway, you order your medicine leeches when you know, when you identify a patient that you think is going to be a good candidate. So this would be someone who has gone through surgery and is having issues connecting tissue. So it's either the skin grafts situations or they've had, you know, their ear amputated, their finger amputated, something that needs to be reattached. Usually what they do is they create a margin of area for the leech therapy, so they put gauze or tape around it, so the leeches don't wander off into places they shouldn't be. And then the way that they apply the leech is really smart. They take an empty syringe, and they take off the tip of it, the front of it. So you just have this empty container and a plunger in the end. And then you use that device to scoop up a leech into the tube. And then you take that tube to the patient's skin. And once the leech is attached at the front of the tube, then use the plunger to gently kind of get them onto the skin and and leave them there to do their thing.
Evan 11:28
That makes total sense. [Yeah, and genius.] And you already have the tools to do it. [Exactly, exactly.]
Kristen Dicks 11:35
Yeah. And so feeding lasts for 30 to 90 minutes, and then they auto-detach. And they usually use anywhere from, I guess, one to 10 leeches per treatment, depending on the area that they need to cover. And they usually use leech therapy twice a day for two to six days. And then after that, they usually see really good success.
Evan 11:57
That's unbelievable. I'm just... [Yeah.] What a marvelous use for these these dear creatures.
Kristen Dicks 12:05
That's right. And I will say, it's not completely without some risk. They have to -- before any procedure that we do to patients, we get informed consent. And this seems to be a particularly special one because there seems to be a bit of an emotional response to having a leech on you. So it takes some coaching. And additionally, the bacteria that I mentioned in the leech gut that helps to process the blood that they're eating -- occasionally, the leech can transmit that bacteria via the leech mouth to the human skin. And so patients can get cellulitis or can get bloodstream infections. [Okay.] So we have to put patients on antibiotics to help prevent those infections when they're undergoing leech therapy.
Evan 12:51
So cellulitis, I mean, how bad, like could it become sepsis? Or...
Kristen Dicks 12:56
Well, it could, if it got into the bloodstream and wasn't treated. But I think once this was recognized early on, they realized that patients need to be on antibiotics. And so usually it's not an issue as long as the patient's getting treated. [I see. I see.] But if someone decided to do this at home without the proper technique and supplies, I mean, you could get sick.
Evan 13:17
So maybe that's an important place for us to tell listeners: Do not try this at home. [Don't try this at home.] Only with trained professionals. [That's right.]
Kristen Dicks 13:28
On the internet, I did find an area of cosmetic leech therapy, which I didn't get into, but it seems like you know, that's a whole another rabbit hole you could go down
Evan 13:36
Seems like a bad idea. Right? [Right.] So when the leeches are stored, they're stored somewhere in the hospital, I imagine. And, what are they fed when they're not fed, uh, us?
Kristen Dicks 13:53
Right? Yeah, so leeches only need to eat once per year. Which is amazing. Yeah. So when they're-- these medicinal leeches are sold, they are usually sold hungry, having been starved, so that they will attach and feed and do their job. And at the company that produces -- I'm not going to say sterile, medicinal leech, but I'll say FDA approved medicinal leeches -- they are kept in these large containers of room temperature or cold water, and they usually put a cloth on top with a rubber band over it so that the leeches can't escape. [Okay.] Which makes them sound like tricky ninjas. And they are fed blood sausages when it's time for them to feed.
Evan 14:45
Blood sausage. Okay, I mean, makes sense, right? [Yeah.] Okay, so, um, it's interesting... So the companies that collect the leeches, they basically starve them, before sending them to the medical facility to use them. Is that...? [That's right.] Is there a kind of sort of cruelty to animals going on here?
Kristen Dicks 15:04
I don't know if it's a cruelty or if it's, we're just taking advantage of their normal life cycle.
Evan 15:09
Okay, okay. Yeah. I mean, maybe the question I'm asking is, to what extent do leeches feel pain? Like, would they feel like, do they feel hungry?
Kristen Dicks 15:17
Do they feel hungry? Oh, gosh, that's a great question. I don't know. I guess when, from a patient standpoint, if you have a non-healing wound, you want them to feel hungry.
Evan 15:29
That's true. [Yeah.] So, speaking of -- I guess hunger just made me think of another question I was thinking about, which, I was reading an article myself on the interwebs -- a lot of great leech information on the internet! It was saying that you should not salt a leech while it's sucking your blood. I think along the lines of you were mentioning some potential risks of leeches. Are there other...maybe this is the public service announcement part of this episode, which is: Are there other things you should not do when you're having leech therapy?
Kristen Dicks 15:58
Well, I think you don't want to lose the leech. [Yes.] I read a couple of reports where leeches got into the wrong place and caused some havoc.
Evan 16:10
Oh, what, what kind of havoc?
Kristen Dicks 16:11
Well, you know, leeches can get anywhere in your body that there's an entrance. So, for example, they can get in your mouth. There was one story...I see you shaking your head. [Don't like that!] I read one report where there was someone who had been drinking spring water and I guess accidentally swallowed a leech and they presented with bloody saliva and they eventually found the leech in the girl's trachea, and it attached in her, in her throat, so... [That's terrifying.] Yeah, you definitely want to make sure they don't get away.
Evan 16:47
I mean, leeches apparently like to be in crevices, right? They like you know, say, armpits. [They like dark spaces. Yeah.] I mean, the, I think the immortal movie scene of leeches is Stand By Me. Have you seen that movie? [Oh, yes. Oh, yes.] And it... Yeah. And it's...The leeches wind up in some "delicate" parts of the body, shall we say?
Kristen Dicks 17:07
Exactly, exactly. Yeah, and I was, I was researching this, you know, when you mentioned the question of pain... I was kind of saddened to hear that once they finished leech therapy, they have to kill the leeches. [No, no.] Yeah, which, which is shocking to think about, but then when you think back you're like, Well of course they do. They just ate a patient's blood. It's not like they could reuse that leech on someone else.
Evan 17:31
It could like -- the blood they had -- they could somehow contaminate the next patient? Is that what you're saying?
Kristen Dicks 17:36
I guess, I guess so. I don't really know how that would go down because it sounds like that leech wouldn't be feeding again for a long time since they feed so infrequently. [Yeah.] So I would hope that you could free them into the environment, but it's probably also not possible because they're being used as a medical device. So they have to be terminated.
Evan 17:56
Right. Okay. Wow. So this adds another layer to the the ethics of leech therapy, right?
Kristen Dicks 18:01
Exactly.
Evan 18:02
I mean, not only are we starving them on the front end, we are killing them on the back end.
Kristen Dicks 18:06
Right. We are we are taking them for everything they have and just throwing them out.
Evan 18:10
And I mean, the irony is that we kind of blamed the victim, right? We say no, you leech, are sucking all the blood out of us. But in fact, we are sucking the life out of them.
Kristen Dicks 18:18
Exactly. Yep. And we had talked about this question of Do you name your leech? Like how comfortable do you get with the leech? And I don't know if I could name my leech if I knew that after I got my leech therapy, he was just gonna get killed. That's kind of sad.
Evan 18:33
Yeah. And that makes me think about -- I think the story you told about the boy with the ear or I think you told me -- before this podcast -- about a kid who they needed a leech to reattach a part of his finger. [Oh, yeah.] He did need to leech. And does the kid who had the... I mean, who named the leech, do they know that that leech is going to die? And if so, is there a kind of grief that comes knowing that your friend leech here has, has given his life for you? [Right.] Or given their life, I should say: leeches are hermaphrodites. Is that right?
Kristen Dicks 19:06
Right. Yes, you're correct. Yeah, it makes you think differently about the way that we feel about leeches. Like I, I came across a leech in a natural environment when I was in Maine, in a lake. I got a leech attached to my foot and was terrified. [Yes.] Thinking that, if I were a person sitting in a hospital bed, so scared about my finger that got cut off or my skin that won't heal, I would be so thankful to have medical leech therapy that worked. You know, so my -- gosh, my emotions would just be so different,
Evan 19:44
Right. Yeah, if you're, I guess context matters, right? If you're in the wild and you see a leech, it's Danger, Danger, Danger. If you're in a hospital and it's needed, and it's explained to you that it's gonna save your life or help you in some way, you would feel like maybe a more complicated set of emotions: gratitude, fear, maybe, as well, but. Okay, this is a... you've complicated my understanding of leeches. [Oh, it goes deep. That's right.] It goes deep. Yes. So, Kristen, would you -- so we've gone through a little bit of the history of medicinal leeches, the current practice. Are you aware of any future uses of leeches or advancements in leech therapy, leech technology?
Kristen Dicks 20:27
Well, scientists are very interested in the kind of proteins that leeches naturally have and the medical benefits of these proteins. So the one that I mentioned, that causes the blood thinning and allows for the bleeding, do you know what that protein is called? Do you have a guess?
Evan 20:47
Anticoagulant? I don't know.
Kristen Dicks 20:50
Well, that's, yeah, that's the broad umbrella. But it's actually called hirudin. [Hirudin!] Hirudin. [Explain that!] Yeah, well that's -- I don't, is that Latin? I don't know. I don't speak Latin. But isn't medical leech therapy, doesn't the stem come from hirudin?
Evan 21:06
Yes. It's hirudotherapy. Yes. [There you go. There you go.] Oh, wow. Okay.
Kristen Dicks 21:08
Yeah. So this -- that one protein, that anticoagulant protein, they have tried to extrapolate that and make into actual treatments they can give to patients outside of leech therapy. And there's one anticoagulant called bivalirudin that is used in hospitals today that I read is related to the protein hirudin in leech therapy. [Wow.] So there already has been some advances.
Evan 21:36
Okay. That's, that's really amazing. You know, it's interesting, I think, at least in my studies, the bloodletting practices with leeches was always this example of how backwards medicine was. And it was usually tied to the Middle Ages. I think you said the 18th century, but it was tied to like all these, these Dark Ages when medicine was so, so terrible. But it sounds like maybe folks back in the day were on to more than they realized. Maybe?
Kristen Dicks 22:09
Yeah, I think, I think you're right. I think they weren't totally wrong. [Yeah.] I think there's definitely a niche like, uh, leech niche for this kind of treatment. If, if you have some kind of microcirculatory compromise that you need to encourage bleeding, because that's basically the great benefit of leech therapy. It's not necessarily while the leeche is attached, it's the bleeding that occurs after the leech is removed, because that anesthetic and the anticoagulant proteins allow for free bleeding from the tissue. And that allows the decrease of that venous congestion and also to promote that circulatory growth, to allow for tissue reconnection.
Evan 22:49
So I love that. And can we like, let's sit with that as a metaphor for a minute -- just to tie everything back to the Leech Podcast here. So if I hear you right, you're saying that the deep benefit of leech therapy is that it allows for circulation and this blood flow that ultimately -- the benefits are seen in healing after the fact? [Yes.] Something like, if I was to make the analogy, it would be: we've watched these movies, they really just are like, painful and they're, the blood is flowing, right? [Oh, yeah.] And yet you step away from it for a while...and you begin to see the healing or the goodness that has come from this film... filmic hirudotherapy. Is it-- Are you with me on that? Or am I just, is that a stretch?
Kristen Dicks 23:36
I absolutely agree. I absolutely agree. My mind is blown.
Evan 23:40
Wow. Okay. Well, maybe on that note, Kristen, are there any movies that come to mind for you that are particularly leechy? [Oh boy.] Or books or TV too? I think we don't want to limit ourselves just to film.
Kristen Dicks 23:57
Mm hmm. I think this is one that we've chatted about before: the movie Parasite. [Oh, yeah.] Yeah, one, a movie that is so well done. Such a good movie. But it made me feel awful while I was watching it. [Oh, yeah.] Yeah. But then, you know, connecting to this thought that you just mentioned (about maybe the rich benefit is really after the leech therapy after the movie) -- it fostered this great conversation that I've had with multiple people about the movie and just, yeah, really broadened my mind in ways that it probably wouldn't have if I hadn't seen the movie. If I hadn't have gone through the pain.
Evan 24:32
Yes. Oh, man. Yes. Said very well. Yes. Agreed. Um, well, are there any other leech, hirudotherapy, things that we should know about? Anything our listeners need to know when it comes to the medicinal uses of leeches? Or even a story? Do you have another story that comes to mind?
Kristen Dicks 24:55
Well, I can-- Should I mentioned the story that we talked about before? [Oh, yeah, great one.] The finger story? [Please!] Yeah. All right. So this I heard from someone else, so this is not my story. But there was a young boy whose finger was cut off. And I don't know what exactly happened -- some traumatic incident. But finger was cut clean off, and so he underwent surgery to have the finger reattached. But in the same way to my first story, the finger just wasn't taking very well. It was looking bruised. It had some venous congestion because the blood wasn't--the blood would flow in, but it wasn't flowing out very well. And so they brought in the leeches. And they attached one or two leeches around the finger per day for a couple days. And it helped with all of that pooled blood and the finger healed and did great.
Evan 25:38
And he did name his leeches. Is that right?
Kristen Dicks 25:42
He did name his leech. Yes. Yeah, the story I was told is that the parents were very queasy about this whole situation, but the kid was fine with it. And the surgeons recommended that the kid name the leech to kind of bond and work through it.
Evan 25:56
Wow. Yeah. Did you catch the name of those leeches that he gave them? By chance?
Kristen Dicks 26:01
No, no, I never heard.
Evan 26:02
Oh man. Well, that is an inspiring story. And I am glad for that child that he now has a finger that is, that is working better, thanks to leeches. [That's right.] Well, Kristen, this has been a joy. I would say, I felt uncomfortable at times, hearing about how this works, but also deeply amazed by leeches and nature. And even just human ingenuity and trying things out with them. But also the complicated feelings about overharvesting of leeches and how we treat them and the ways they become expendable for us. So you've really complicated my understanding of leeches. And thank you.
Kristen Dicks 26:54
Absolutely. Happy to help.
Evan 26:57
It's amazing. Well, we might, we might need you to come back on the pod at some point as our expert Leech Therapist. And if you do come up with some more Leech movies that, that that you've seen, and want to be a guest host with us, we'd love to have you anytime on The Leech. [Sounds awesome.] Great. Well, thanks again to Dr. Kristen Dicks. And this has been a special bonus podcast from The Leech pond. Again, this is a show about movies that suck the life out of you, and also stick with you. I'm Evan Cate. Thanks for listening. See y'all soon.