A leech is a form of segmented worm. They swim in water and move across land. A sucker exists at each end of the leech's body. It does not have legs nor does it have gills or lungs for respiration. Several fine blood vessels located near the surface of the leech's body take oxygen in and give off carbon dioxide. Leeches not only feed off of blood, but they eat tadpoles, snails, and other small animals residing in ponds.
For centuries, leeches have used for a variety of medical purposes including bloodletting and post-surgical treatments.
Medicinal Leech Therapy
Post-surgery, the fresh blood containing oxygen from the lungs goes directly to the surgical area. The old blood then has an issue leaving the surgical area and getting back to the lungs and heart. The old blood causes the area to become cold and dark in color.
Leeches are attached to the discolored area to suck out the old blood, allowing fresh blood to enter the area. The leeches can feed anywhere from 10 minutes up to an hour. They suck 1 to 2 teaspoons of blood during a feeding. Once the leeches are done feeding, they will fall off of the area. The leeches are not reused and are placed in a container of alcohol to die.
Treating Kasabach-Merritt Syndrome
Kasabach-Merritt Syndrome is characterized by low platelets, destroyed red blood cells, fast growing vascular tumors, or impaired clotting. While feeding, leeches secrete hirudin, which is an anticoagulant that prevents blood from clotting.
During reattachment or transplant surgery and flap surgery, the two ends of the arteries are easy to attach, due to the arteries being thick-walled. Veins, on the other hand, are thin-walled and can be difficult to attach. As a result, the blood going into the reattached body part/flap becomes stagnant, because the veins aren't able to get the blood out.
Leeches take over the job of the veins, sucking out the used blood, allowing fresh blood to enter the area and keep the it healthy. This allows the veins more time to heal.
Leeches produce an anticoagulant called hirudin, which can inhibit blood clotting for four or more hours. Hirudin has been proven to benefit heart patients who have had heart attacks, angina, or angioplasty.