Creepy Crawly Care: Medicinal Leeches in Modern Medicine

An age-old treatment, medicinal leeches have made a comeback as emergency salvage therapy when surgical options fail to re-establish blood flow after tissue grafting and limb re-attachment surgery.

The Hirudo medicinalis leech has 300 sharp teeth within the muscular head sucker.

Photo courtesy of Ricarimpex.

Leeches are being prescribed by Canadian surgeons to remove pools of congested blood after operations to re-attach severed fingers, ears and other body parts. Pooled blood interferes with circulation and can cause tissue death.[1]

The Benefit of the Bite

A leech bite in the grafted or replanted area removes about 5 mL of congested blood. However, the major therapeutic benefit is linked to natural anticoagulants and vasodilators in the leech saliva that cause the bite wound to ooze blood (up to 50 mL) for six or more hours following detachment.[2]

New leeches are applied several times daily for three to seven days until new blood vessels grow and restore regular blood flow in the affected tissue.[1]

Cost

Leeches cost US$9.45 each. Same-day delivery can add significantly to the cost. Toronto-based Canada World Wide is the distributor for Leeches U.S.A. Ltd. (Westbury, NY), which imports the leeches from Ricarimpex SAS, in France.

Patient Population

The frequency of leech use following reconstructive and plastic surgery in Canada is unknown. According to Rudy Rosenberg, co-owner of Leeches U.S.A. Ltd., approximately 8,000 leeches were shipped to Canadian hospitals in 2005, a number that has been steadily increasing during the last 20 years.

Regulatory Status

The US Food and Drug Administration approved Hirudo medicinalis as a medical device in June 2004.[1] Medicinal leeches are regulated as biologic products by Health Canada’s Biologics and Genetic Therapies Directorate.

Evidence

A meta-analysis of 36 reports of medicinal leech use after tissue grafting in 108 patients showed that tissue that would have otherwise required debridement or amputation was successfully salvaged in 70% to 80% of cases.[3]

Patient Care Implications

Applying and monitoring leech therapy requires significant nursing staff time to ensure that leeches do not feed on healthy tissue or migrate during treatment. Bite wounds require close monitoring after the leech detaches. Patient acceptance of leech therapy depends largely on thorough pre-treatment counselling.

Treatment Risk

The risks associated with leech therapy include infection, excessive blood loss requiring transfusion, migration of leeches into body orifices and allergic reactions to leech saliva. Leeches have the potential to transmit blood-borne viruses such as hepatitis and HIV. They are intended for single use only and must be handled as biohazardous waste.[2] Prophylactic intravenous antibiotics are recommended to protect patients against leech bacteria.[2]

Hospital Policies

Hospital staff must be familiar with procedures for the safe acquisition, storage, dispensing and disposal of these live parasites. A standardized protocol will help meet the challenges of using this therapy.

References

[1] Horowitz S. Altern Complement Ther 2005;11(1):12-6.

[2] Weinfeld AB, et al. Ann Plast Surg 2000;45(2):207-12.

[3 ]de Chalain TM. J Reconstr Microsurg 1996;12(3):165-72.