Leeches

LEECHES, used for medical purposes, belong to the type of annelids (Annelida), class Hirudinea, order Gnathobdellida. They live in fresh standing waters (marshes, ponds, ditches). Their lifespan is several years. Many species are suitable for blood extraction. In Europe, particularly in the USSR, the medicinal species Hirudo (s. Sanguisuga) medicinalis and Hirudo officinalis are used predominantly; these should not be confused with horse leeches (Hirudo sanguisorba). Leeches have an elongated flattened body composed of rings and capable of strong contraction; the length of an adult leech is 3–6 cm, the transverse diameter 10–12 mm, weight 1¹/*–3 g. At the narrowed head end there is a sucker, at the bottom of which the mouth opens with 3 jaws radiating outwards. The jaws are shaped like small saws with teeth, numbering 90, with which the leech pierces the body covering. At the tail, thickened end there is a second sucker of larger size, with which the leech can attach in place or move forward. Medical leeches—back is olive-green, often almost black, with 6 narrow reddish longitudinal stripes; belly is also olive-green with black spots. Pharmaceutical leeches—back without stripes; belly with 2 black longitudinal stripes. Horse leeches—greenish-brown with black, fairly densely located spots. Only healthy, hungry leeches, moving quickly in water and having a thin body when stretched, which contracts strongly (3–4 times) upon contact, are suitable for use; the body of such a leech is elastic and slippery to the touch. Lethargic movements, knots of hardening, and a sticky surface indicate a diseased state of the leech and its unsuitability for use. To avoid transmitting infection from one patient to another, leeches that have never been used are generally applied. In case of insufficient stock of leeches, they have to be used repeatedly; in this case, after use, the blood must be squeezed from the engorged leech into water acidified with vinegar or salted and kept hungry for several months, since the remaining blood in it digests extremely slowly. Leeches suck best at 3–5 years of age, weighing about 1–2 g. Such a leech can suck 10–15 cm³ of blood. When sucking blood, the leech releases hirudin (see) into the wound, due to which blood flows from the wound for quite a long time after the leech is removed. Indications. Leeches are used along with other methods of blood extraction, but they have a slightly different effect, since they reduce blood coagulability. At the same time, they can be applied where blood-sucking jars cannot be attached, namely: behind the ears, in the coccygeal region, at the anus, on the gums, on the cervix, as well as in places where the skin is inflamed and the underlying tissues are very painful. According to Zakharin, who used them very widely and with great success in many diseases, the distracting action of leeches has even greater significance in many cases than the extraction of blood in the area of their application, and is expressed in the fact that with hyperemia of the brain and spinal cord with a tendency to hemorrhage, as well as with venous stasis in the liver, lungs, and uterus, attaching several (2–7) leeches to the coccygeal region can quickly regulate circulation, eliminate many severe symptoms, and stop bleeding from the nose or hemoptysis. Thus, the use of leeches is considered indicated: 1. For blood extraction, in which leeches are mostly attached in the mastoid process area during blood influx to the brain, especially with threatening hemorrhage, and with inflammation of the middle ear; to the nasal septum—during painful hyperemia of the head with blood influx to the face in the initial stage of infectious diseases (chiefly typhoid state); in the spinal region—during inflammation of the meninges; along the right costal arch—during acute pericholecystitis, as well as during blood stasis in the liver; in the anterior superior iliac spine area—during acute perityphlitis; to the cervix—during its hyperemia; to the coccyx—during acute hemorrhoidal phlebitis. 2. For blood diversion, according to Zakharin's indications, leeches are attached predominantly to the coccyx. 3. For general bloodletting, it may be necessary to apply leeches only in cases where, for some reason, venesection cannot be performed or blood-sucking jars cannot be placed. The negative side of using leeches is considered to be the impossibility of accurately determining the amount of blood extracted and maintaining complete asepsis. For attaching leeches, a place is chosen where the skin is not too thin and less sensitive to pain, and where the subcutaneous fat is not too loose, otherwise extensive infiltration with blood may result. Leeches cannot be placed where vessels—veins or arteries—pass directly under the skin. Cases of leeches piercing superficial veins have been observed. Leeches cannot be placed in conspicuous places, especially in women, since after use star-shaped, characteristic, often very noticeable scars remain. Leeches do not attach where the skin is very dense, especially on the palms and soles. Leeches can crawl into natural openings; therefore, having in mind to place them nearby, it is necessary to first insert a cotton tampon soaked in oil there. At the place of leech attachment, the skin is shaved, washed with soap and water, and dried, vigorously rubbing with a towel to cause blood influx, due to which leeches attach more willingly. For the same purpose, the skin should be moistened with sugar water or blood from a very superficial incision or prick; this is especially useful on inflamed places where leeches attach reluctantly. -Method of application. Leeches are attached in various ways; if one leech needs to be attached, it is grasped by the fingers near the head end, applied to the skin, and held until it attaches. It is much more convenient to place the leech head end in a glass or on a playing card, making a tube out of it, and then pull it out from under the leech when it attaches, without risking tearing it from the wound. If the leech falls off quickly after attaching, it is replaced by another. If it has attached, it should not be touched, as it may fall off upon contact. If it is necessary to remove the leech before it falls off on its own, it should not be pulled, but simply sprinkled with salt or moistened with salted or acidified water; it is also possible to cut it with scissors or pierce it with a needle, after which it dies. To continue bleeding, it is sufficient to apply warm moist compresses to the bite site. If, however, bleeding must be stopped immediately, a dry compressive bandage is applied. Healing of bites under aseptic bandage occurs within 2–3 days. Application of leeches in individual areas. 1. On the gums, the leech is held in a glass tube and after it has attached, to prevent it from crawling into the oral cavity. If the patient swallowed the leech, he should be given to drink brine or wine. 2. When applying leeches to the uterus, first of all a cylindrical mirror must be inserted and pressed tightly against the vaults of the vagina so that the leech does not escape; then, inserting a glass tube with a leech through the opening of the mirror, it is allowed to attach to the cervix. If the cervix is gaping, it is tamponed beforehand; it is also recommended to hold the leech on a thread tied around its tail end. Prolonged bleeding after attaching leeches can be dangerous, especially in children. If bleeding does not stop with a compressive bandage, hemostatic agents (see) are applied. If there is no certainty that bleeding has stopped completely, appropriate surgical measures are taken. Infection of the wound with unsatisfactory technique of using leeches has been observed in the form of lymphangitis, phlegmon, erysipelas, and even tissue necrosis.