Leech therapy, once thought of only as a good horror movie element, has experienced a modern medical practice revival across the United State and Europe. In 2004 the United States Food and Drug Administration officially approved leeches as a medical device ^{1, 13}. However, leeches and the practice of placing living leeches on a patient (known as “leeching”), is by no means a new medicinal practice.

There is documented evidence of leeching dating back all the way to the beginning of the Common Era. Leeches have been used for centuries in nearly every major culture as a tool in "bloodletting" ⁵. Interestingly, bloodletting was the most common worldwide medical practice performed by physicians from antiquity until the late 19^th century ⁵. Bloodletting is in essence the practice of withdrawing blood from a patient in order to cure or prevent illness and disease ⁵. Bloodletting and the use of leeches truly boomed in the early 19^th century and thus made the production and sale of leeches a very profitable business. In fact, most of the modern large scale producers of medicinal leeches were founded in the early 1800’s.

Although the uses for leeches have evolved since antiquity, the actual species of leech used in Western Europe and America has remained the same. Hirudo Medicinalis, the European medicinal leech, is the most common leech used in modern medical practice ^{1, 2, 5}. This leech is an aquatic segmented worm and can typically consume 5 -20 mL of blood in one application ⁵. The European Medicinal Leech has three jaws which each have approximately 100 teeth. This variety of leech releases an anesthetic into the wound when it bites, which helps to make the bite relatively painless ^{1, 2, 9}. Once the leech has attached to the wound it naturally injects powerful compounds to help inhibit coagulation of the blood and sustain continuous blood flow:

• Hirudin: a powerful anticoagulant and one of the most potent natural inhibitors of thrombin ^{5, 9}.
• Calin: an anticoagulant that prohibits the Von Willebrand factor to bind itself to collagen. This is also an effective inhibitor of the platelet aggregation caused by collagen^{5, 9}.
• Leech saliva also contains a naturally produced histamine-like substances that help to induce vasodilation ^{5, 6}.

In regards to leech storage the modern leech farm facilities provide detailed protocols for their specific leeches. This normally includes a cool temperature (40-45 degrees Fahrenheit) within a storage container of a specific distilled water solution ¹.

Leech therapy generally involves four main stages:

1. The initial bite – typically painless due to the anesthetic that is secreted in the leech’s saliva.

2. An attachment period – this can last from 15 minutes to 60 minutes ¹. This is the period in which the leech is attached and sucking blood. A normal individual leech can consume between 5 -20mL of blood ^{1, 5, 6}.

3. Post Attachment period – At some point during the attachment period the leech will de-attach on its own when satiated. Feeding times vary – the patient should be instructed to notify the nurse as soon as a leech detaches. After the leech detaches the site will continue to bleed.

Note: It is not advisable to try and force the removal of leeches ¹. In certain cases forced removal (with forceps or hands) damages the leeches and can even leave parts of the jaw and teeth attached to the site.

4. Leech Disposal – Once the leech has detached on its own the leech can be placed in a small cup with alcohol ^{1, 5}. The leech will die and should then be treated as bio-hazardous waste. Each cup should be labeled with patient’s name and the date.

Note: Leeches should never be reused on another person. Also, once a leech feeds and is full it will not be interested in feeding for several weeks ⁶.

Modern applications for leeches are extremely varied: ranging from the common usage during tissue grafts and plastic surgery to uncommon cases of being used in the treatment of systemic lupus erythematosus and during penile replantation ^{1, 5, 7} . The majority of present day leech applications revolve around situations in which severed arteries are reconnected by suturing ⁴.

In procedures such as reattaching severed body parts or tissue graft procedures the arteries may be able to be reconnected but the veins may be difficult to suture. Blood flow may then become restored through the arteries but not the veins and the blood in the attached body part or tissue may then become stagnant or congested. The reattached part will then turn blue and lifeless and become at serious risk of being lost. The leeches can help to reduce the congestion by removing blood which is currently unable to exit the area through the venous system ⁴.

As with any treatment option a detailed patient assessment should be performed. In a situation involving venous congestion the patient’s tissue will have a purple appearance and be engorged, taut, and warm to touch. Although leeches have been found to be an effective clinical treatment option to relieving venous congestion there are several contraindications to leech treatment:

• Leech treatment should be avoided in patients with HIV and AIDS³.
• Leech treatment should be avoided in patients who are on immunosuppressive drugs.
• Leech treatment should be avoided in patients who have preexisting arterial insufficiency.
• Leech treatment should be avoided in patients with bleeding disorder³.
• If a patient refuses to accept blood transfusions then leech treatment should be avoided.

A nurse should check with the patient in regards to any vitamins, supplements, or drugs that he or she may be taking. Caffeine consumption and smoking should be stopped since both contain compounds that raise the risk of vasoconstriction⁶.

As with any treatment option there are risks that must be evaluated. In the case of leeches, there is a risk of infection – specifically Aeromonas Hydrophila. This bacterium is found in the gut of the leech and in very rare cases can be transmitted to the patient.

Infections can present 2 to 11 days after the first therapy and can result in abscesses and cellulitis (and in extreme cases sepsis). Antibiotics can be used to combat the bacteria however the potential risk of infection through the use of leeches does exist.

During patient assessment you may find that the patient is extremely resistant to the idea of undergoing a leech treatment. In these situations education and a detailed explanation of how leeches can help is crucial to overcoming an initial hesitation⁶. Some nurses have found that showing the patient a before and after photo of a similar wound can help persuade them.

A normal leech treatment order should include the amount of leeches to be used, the frequency of treatment, and the specific area where the leeches are to be used.

• To begin, clean the patient’s skin thoroughly with soap and water to remove all substances that may have a strong order or taste ⁸ . Rinse the cleaned areas with distilled (non-chlorinated) water.
• While wearing gloves, gently hold the leech and guide the head towards the site.
  • The head is normally the smaller side that seems to be probing around, the tail end is typically used as a suction and does not move as much ^{1, 10} .
  • Smaller leeches tend to be the “hungrier” ones. Start with these and work your way towards the larger ones ⁶.
  • Avoid using forceps as this can damage the leech ⁶.
• Some practitioners prefer to make barriers with pre-cut holes in a sheet of op-site dressing or gauze in order to prevent the leeches from wandering around ² .
• If the leech seems reluctant to attach there are several tips towards convincing it:
  • Make a small needle prick on the skin to produce a tiny droplet of blood ^{1, 6} .
  • Place a small drop of glucose at the desired site. The leech should be drawn to the sweet taste.
• Once the leech is satisfied it may simply drop off of the skin or begin to move around on the skin. The patient should notify the nurse of any leeches that have detached so that they can be properly disposed of.
  • If blood supply seems poor and the leeches are becoming unattached quickly, the original diagnosis of venous congestion may have been incorrect ¹ .
• During the course of the treatment the patient should be monitored every 15 minutes to check for detachment or any adverse symptoms. In the event that a leech has migrated from the desired treatment site to another site you can try to nudge the leech with an empty syringe. If that does not work try rubbing a cotton swab doused in a small amount of vinegar or alcohol on the head of the leech.
  • Be careful when rubbing vinegar or alcohol on the leech – these compounds are toxic to the leech and if too much is applied the leech may regurgitate back into the open wound ⁶.
• A nurse should perform a detailed evaluation of the site at least every four hours. This can include checking the temperature of the skin (it should be warm – about 86 degrees Fahrenheit), checking for infection, checking the pulses near the site, and checking basic laboratory values ¹.
  • If any abnormal findings are noticed, the physician should be notified immediately.

• Any unused leeches can be returned to their sterile water storage ¹ .
• Leeches that have fed should be disposed of humanely - Leeches, although classified as medicinal devices, are living creatures ¹ . They can be narcotized with 8% alcohol and then placed in 70% alcohol in a larger container for at least 5 minutes ¹ . Afterwards they should be treated as bio hazardous waste.
• Important note – never reuse a leech on a second patient and never return a used leech to a pharmacy ^{1, 2, 8} .
• Interestingly, the major benefits of leech therapy occur during the post-bite period. Each bite should be encouraged to bleed by the gentle removal of any locally forming clots at regular intervals.
• The area around the leech bite wound should be closely monitored for local infection. In the event that bleeding is severely prolonged, hemoglobin levels should be checked daily.

Be sure to document the appearance of the site before the treatment and after the treatment. Also, document the time, location, and duration of each leech application. Patients usually require leech treatment for 2 – 10 days.

Although leech therapy is an ancient practice, it has direct benefits for the modern patient. Patients may
be hesitant at first, but when faced with the option of a lost finger or tissue section or leech therapy the
hesitation should subside. As with any form of medical treatment, care and detailed assessments are
necessary in order to reduce potential complications and to drive positive outcomes.

(1)Applying Leeches. (2014). Biopharm Leeches. Retrieved from: http://www.biopharm-leeches.com/applying.html
(2)Conroy FJ, et al. (2006). The prevention of migration during leech therapy. Plastic Reconstructive Surgery. 117 (7), 25-39.
(3)Contraindication for Leech Application. (2010). Biopharm Leeches. Retrieved from: http://www.biopharm-leeches.com/contraindications.html
(4)How Do Leeches Work? (2014). Biopharm Leeches. Retrieved from: http://www.biopharm-leeches.com/clinical.html
(5)Leeching. (2014). Encyclopedia Britannica. Retrieved from: http://www.britannica.com/EBchecked/topic/750132/leeching
(6)Newsom, Kandance, Yantis, Mary Ann, and Ring, Patricia. (2009). Leech Therapy. The American Journal of Nursing. April 109 (4), 36-42.
(7)Pantuck, Allan, Lobis, Michael, Ciocca, Rocco, Weiss, Robert. (1996). Penile Replantation Using the Leech Hirudo Medicinalis. Urology. 48(6), 953-956. DOI: http://dx.doi.org/10.1016/S0090-4295(96)00318-4
(8)Pullen, Richard. (2010). Using Leeches To Treat Wounds. Nursing. 40 (3), 62. DOI: 10.1097/01.NURSE.0000368825.43217.03
(9)The Benefits of Leech Therapy and Its Effects. (2014). Mehdi Leech Therapist. Retrieved from: http://www.leechestherapy.com/benefits_and_effects.php
(10)Treating Diseases with Leech Therapy. (2014). Mehdi Leech Therapist. Retrieved from: http://www.leechestherapy.com/treating_diseases.php
(11)Use of Leech Therapy in Patients with Skin Grafts. (2014). Mehdi Leech Therapist. Retrieved from: http://www.leechestherapy.com/skin_grafts.php
(12)Wells MD, Manktelow RT, Boyd JB, Bowen V. (1993). The medical leech: an old treatment revisited. Microsurgery 14 (3), 183–6. DOI:10.1002/micr.1920140309.
(13)Wong, Cathy. (2011). FDA Clears Medicinal Leeches. Retrieved from: http://altmedicine.about.com/od/consumerreviewsalerts/a/Leeches.htm