Are Leeches Still Used In Medicine

Medicinal bloodletting has been practiced since the Stone Historic period. The popularity of leech therapy as a treatment has varied over time, just they notwithstanding have a apply in modern surgery.

The species of leech used for medicinal purposes is Hirudo medicinalis. Each leech tin consume about 5 to 10 ml of blood at each feeding, almost 10 times its own weight. They have three jaws and a hundred teeth. As they seize with teeth, they inject an anaesthetic into the skin and their saliva contains anticoagulants which finish the blood clotting.

Leeches 1: Hirudo medicinalis

Image from Pixabay, free to use (CC0 one.0).

So why are surgeons using the leech therapeutically once again? The medicinal use of leeches — scientifically known as hirudotherapy — re-emerged in the 1970s. Leeches have a useful function in reconstructive and microsurgery where they tin relieve venous congestion. For example, when a surgeon reattaches a severed finger, it is much more hard to repair the smaller veins than the big ones, so the finger can go bloated with blood. The hungry leech sucks out the backlog blood slowly and steadily, which keeps the finger healthy while the veins knit together and heal. The anticoagulants continue the blood thin, so that clots don't class and create problems. It'due south an constructive treatment with few side effects.

The history of the medicinal leech is fascinating. In antiquity, Pliny the Elder (AD 23–79) recommended leeches to treat phlebitis and haemorrhoids, while Egyptian medics believed the leech could help cure everything from fevers to flatulence. For centuries, patients were bled to restore a supposed imbalance in bodily humours.

Leeches 2: Application Humorism identified four humours that existed as liquids within the body: blood, phlegm, black bile and yellow bile. A good remainder between the 4 humours was essential to remain healthy and an imbalance could result in disease. By the end of the Middle-Ages, doctors were using leeches to care for a wide range of disorders, including nervous organization diseases, urinary and reproductive problems, inflammatory and center diseases.

Right: A medical practitioner administers leeches to a patient. Colour lithograph after L. Boilly, 1827. From the Wellcome Collection, gratuitous to employ with attribution (CC BY 4.0).

Medicinal leeching reached a pinnacle in the 18^thursday and 19^th centuries. The theories published by the Napoleonic surgeon François-Joseph-Victor Broussais created a stir and a market place for leeches. Leech trading became a lucrative business, with leeches exported across Europe and to the USA. France alone required millions of leeches annually. The use of medicinal leeches began to decline around the 1830s as diagnostic medical skills improved. John Haycraft'south publication,On the action of a secretion obtained from the medicinal leech on the coagulation of the blood (1884), showed that the blood in a leech'due south gut doesn't coagulate and the isolation of this anticoagulant, hirudin, past Fritz Markwardt in the 1950s, ensured the standing importance of the leech in medicine.

Leeches 3: Practical treatise

Leeches 4: KCH Pharmacopeia 2016 Many books and papers have been published over the years, and the field of study is scattered throughout the RCS Library collections, as you would expect given the popularity of the treatment. Some of the xix^th century material has been digitised as part of the Uk Medical Heritage Library project. For instance, A practical treatise on the efficacy of bloodletting, in the epidemic fever of Edinburgh past Benjamin Welsh looks at the evidence for using leeches in fever cases during an outbreak in 1819. He describes treatment of 44 individuals in item, as can be seen in this extract on Joseph Burkett, a Flaxman (he survives). Welsh summarised his treatment: "Very sharp case. An splendid example of the efficacy of haemorrhage at a late period of the affliction; instantaneous relief from the evacuation." Further data is included on the environment, and tables covering age, symptoms and the number of leeches used are included. The leech continued to be used regularly, as this example from the 1916 Rex'south College Infirmary Pharmacopoeia giving the procedure for applying a leech to the patient shows.

In the past, leeches were harvested from the wild and kept in leech jars filled with rainwater, which were often decorative. Leeches could be reused: you either waited until they'd digested their meal or persuaded them to disgorge the blood. Now to avoid infection, they are peculiarly bred and grown for medical use and humanely disposed of after one utilize. Modern leech therapy has fewer applications than in the past, simply is supported by scientific studies and instance reports; research continues into their use in a number of medical fields.

Susan Isaac, Information Services Manager