Leeches: Friends or Foes
Tra T. Nguyen, M.D., Otolaryngologist

Tường Trình Trường Hợp Lâm Sàng Bị Đỉa Cắn
Bs Nguyễn Thanh Trà, Chuyên Khoa Bệnh Tai Mũi Họng

Leeches can cause serious morbidity but also are used, over the ages in therapy. Leeches have been reported harming both animals and humans.
Leeches are annelids or segmented worms, hermaphrodites, blood sucking parasites. They vary in color (black, red, or mottled) range in length between few millimiters to few centimeters, they are cylindrical or leaf like in shape. Leeches can be found in the tropics and temperate zones, in infested waters and in swampy tropical vegetation and bogs. The leeches suck blood using powerful jaws and muscular suckers at both anterior and posterior ends; its saliva contains an anticoagulant factor: hirudin which inhibits thrombin and factor 1a and hementerin causing bleeding. In animals, attacks on hunting dogs, camel, ducks, turtles are well documented in the Mediterranean countries, in Africa, Asia, and Europe. In these animals, leeches were described to act as foreign bodies and parasites into the respiratory tract. In humans, leeches can cause severe bleeding: epistaxis, pharyngeal bleeding, hemoptysis, hematoemasis, vaginal bleeding (depending on the port of entry). Leeches bite to various sites: nose, pharynx, larynx, esophagus, rectum, bladder, vagina have been reported sporadically in the literature.
Case report:
In the late 60’s, on assignment to the ENT Dept. in the largest Military Hospital in the outskirt of Saigon, I happened to see a young soldier with the history of severe nasal and postnasal bleeding, for the past 5 weeks. He was evacuated from a provincial hospital after multiple repeated nasal packings that failed to control the bleeding. The patient was obviously in tremendous pain, very weak and severe anemic. He can barely sit in the exam chair with the help of a nurse. The patient’s face was swollen due to the large amount of packings in both nasal fossae. I could not ask any question and I will never forget the patient’s stare of despair and his expression of distrust in doctors that so far, only replaced his nasal packings causing more pain and bleeding with no end in sight!
I realized that I had a very short window of time to find the etiology of his bleeding and stop it before I lost the patient. The mistake would be to remove the packings and try to examine the nose, the bleeding will be so brisk that the only choice would be to repack the nose. Instead, I try to visualize the nasopharynx with a small mirror, I saw a red fleshy mass in the middle of the posterior noses, I was thinking of a tumor or a vascular malformation (juvenile angiofibroma). With a second look with the mirror, I was totally surprised to find the red mass was moving! At the moment, I realized that must be a leech that suck out the blood from this patient. The patient was then sent to the OR and under general anesthesia the leech was retrieved with forceps, the bleeding ended and the nasal packings removed safely.
Another case??
When I was a youngster on vacation in the countryside of Viet Nam, I heard a story, repeated with so much fervor that there must be truth to it, although nobody could explain how that could happen. A mother surprised her daughter in law to cover the clay rice cooker to ease the severe headaches. She suffered for some time. The mother in law was so enraged that she striked the daughter’s head with a baton and fractured the girl’s skull and discovered that a part of the brain was destroyed and replaced by a colony of leeches!
For a long time, I believe that it was of these tragic endings trying to explain the proverbial conflict mother and the daughter in law. But later, I saw a patient in my practice with a complain of severe dizziness and I found a large open cavity behind the ear without any previous surgery, I understood that there was a possible pathway to the brain from an open mastoid where leeches can eat their way to the middle cranial fossa through the tegmen tympani (thin layer of bone separating the mastoid from the brain and that bone could be dehiscent).
Leeches Use in Medicine: Leech Therapy or Hirudotherapy
For over 2000 years, leeches were applied to may ailments as adjunct to blood letting in Asia, Europe. Since the early 60’s there was a revival of leech therapy, especially in Plastic and Reconstructive Surgery. Historically, leeches collectors would wade in leech infested waters and allowed the leeches to attach themselves to their legs. Nowadays, leeches for medical use, are bred in Laboratories under sterile condition to reduce infections in patients. Two US companies sell medicinal leeches for 7.50$ a piece, they are usually on call in hospital pharmacy refrigerators. As the leeches suck blood, they released an anticoagulant called hirudin that stops the blood from the clothing. This action can last up to 6 hrs after the leeche is detached from the patient. The feeding process of a leech about 20-40 mn and the body size can increase to 10 times their original size. Once the leech is full, it will release itself and drop off.
Leeches remove edema, had a drainage effect, restored microcirculation.
In Plastic and Reconstructive Surgery, before grafted tissues gets new vein growth, it can become congested with blood, and the graft may fail. This is when the leeches can suck out excess of blood. An ENT Surgeon from the University of Michigan treated 2-3 patients a year with leeches after rebuilding faces or mouth invaded by cancer. Leeches are also used in the treatment of a wide range of diseases:
- Cardiovascular diseases (hypertension, ischemic diseases of the heart, stroke prophylaxis, thrombosis, thrombophlebitis, varicose veins, trophic ulcer), a particular mention of Buerher’s diseases (thromboagiitis obliterans), inflammatory occlusion of peripheral arteries, causing circulatory disorders. Beside the usual treatment of this disease: stop smoking, focal care of ischemic ulcer, anticoagulant, vasodilator, and platelet, the addition of leeches could help to avoid amputation or bypass graft.
- Gynecological disorders: acute and chronic inflammatory process, hysteromyomas.
- Neurological diseases: headaches, neuralgia, neuropathy.
- Urological diseases: chronic prostates, prostate adenoma, chronic pyelonephritis.
Hirudin, contained in leeches saliva is being developed for experimental use as systemic anticoagulant. US magazine reported that a number of Hollywood celebrities are swearing by leech therapy to keep themselves toxin free, youthful and looking sexy way pass their prime!
Complications of Hirudotherapy:
- Infection by bacteria that the lechers may cary and pass on; broad spectrum antibiotics should be used.
- Excessive blood loss.
- Loss of leeches in body orifice and spaces.
- Allergic reactions such as itching, wheal formation and blisters.

Although rare, leeches causing diseases should be part of the differential diagnosis, especially in cases of persistent bleeding or airway obstruction in children of unknown etiology,
Leeches play an important role in Modern Medicine and should belong to our therapeutic armamentarium.

References:
Alavi, K (1969) Epistaxis and hemoptysis due to Hirido medicinalis. Arch OTO 90, 178-179.
Bilgen, C. (2002) A nasopharyngeal mass: leech. Int. J. of Pediatrics OTO 64, 73-76.
El-Awad M.E. (1990) Haematemesis due to leech. Annals Tropical Paediatrics 10: 61-62.
Gerlach, A. (1975) Leeches in the respiratory system. Laryngologie, Rhinologie, Otologie 54, 123-132.
Mohammad, Y. (2002) Laryngeal hirudiniasis. Pediatric Pulmonology 33, 224-226.
Uygur, K. (2003) Removal of a laryngeal leech. American Journal of OTO 24, 338-340.

Nguyễn Thanh Trà, M.D.

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