If you are my sister, or if you are eating, skip this post.
I got a question the other day from a friend of mine about maggots and leeches. Specifically, she wanted to know what sorts of situations warrant the use of maggots or leeches, and how on earth maggot therapy or leech therapy actually works.
So I thought I'd put the answers up here. If you're a lay person or have never worked with leeches or maggots, or even if you have, you might find the following kind of icky.
Maggots are the larvae of flies. They hatch from eggs and spend their lives as larvae eating dead (and sometimes living) tissue, feces, dead plant material, what-have-you. Maggots are the obsessive-compulsive garbage men of the natural world. With the exception of a couple of species of beetle (one of which is kept specifically for cleaning the bones for display skeletons), no critter is better at eatin' dead stuff and gettin' it out of the way.
In certain situations tissue will die. Let's take the example of a diabetic person with a nasty wound on his foot: because the nerves in his foot have died off as a result of his diabetes, and because there isn't a lot of blood circulation there ditto, the wound has gotten truly horrible. As in, gangrenous, black, bits of infected crap hither and yon, eating into the deeper structure of the foot.
(Here I'm describing a wound I actually saw, though not the worst one. The worst diabetic foot I ever saw had four toes that came off in the bandages when I unwrapped them.)
Okay, so dude has a bad foot wound. Standard practice would normally be to do a "sharp debridement" of the wound--in English, that means snipping away the dead tissue (it doesn't hurt)--in order to let the underlying healthy stuff grow and heal the problem. Unfortunately, there are a number of situations in which sharp debridement isn't an option. If the wound is too big, or too deep, or the proportion of dead tissue is truly awful, or if the structures involved are really delicate, you don't want to get in there and just start scissoring away.
So we send in the maggots. ("Isn't it rich? Aren't we a pair? Me in a hole in his foot, you in his hair?")
Maggots do three really cool things: They eat dead tissue, they *don't* eat live tissue (if you have the correct species), and they sweat antibiotic goo out of their skins. So they're perfect for cleaning out really icky wounds.
Plus, since they're sterile (both ways, in that they're non-infective and won't turn into flies), they're easy to get *out* of the wound. You put 'em in, cover the area with a loose bandage, warn the patient not to soak the affected bit in water, and three weeks later, hey presto! Big fat maggots that fall out and have to be wrangled across the floor.
Which is the downside--collecting them all after they come out of the bandage. But it's worth it, to be able to look at a formerly-necrotic, stinking wound that would've otherwise necessitated amputation, and see healthy pink granulating tissue.
Don't disrespect the leech. It could be your best friend if you have the misfortune or poor judgement to, say, stick your head inside the business end of a combine and get your ear torn off. (Yes, another actual case.) (Or if you have, say, major facial trauma or limb trauma with a lot of bruising and hemorrhage under the skin.)
The patient, whom I'll call Albert E., had had his ear reattached but had developed a fairly common complication of tricky teeny-eeny plastic surgery: the reattached ear had gotten congested with blood. The swelling was such that it threatened to cut off blood supply to the ear and kill the tissue, so we stuck a couple of leeches on the worst-off parts of the ear and scalp.
Leeches are easy to work with. They don't talk politics and they don't take breaks. They also have both an anticoagulant and (if I'm remembering right) an anesthetic in their spit, so it doesn't hurt the person to have a couple of purply-black worms on their skin. The absolute worst thing that can happen with leech therapy is that a leech is yanked off before it's done feeding: in that case, the mouthparts might be left behind, causing an infection.
The second-worst thing that can happen is that a leech attaches itself to someone other than the patient, like the nurse. Which is why you always wear gloves and use forceps in handling the little guys.
Leeches are also a biohazard, in that they're full of human blood, so you can't just toss 'em in the trash. We dispose of ours in containers of rubbing alcohol (yikes eek ow yuck gar ick) and then in sharps containers after we've put that Sorb-O stuff in the alcohol.
There you have it: The two grossest things you're ever likely to see working as a nurse (or being a patient)--but with the redeeming quality that they're actually useful.