Don't look now - there are leeches in the ICU!

Leeches. Yuck. We fear we´ll find them stuck to our legs after a dip in
the lake but... believe it or not, they serve a medical purpose too!

This is a fresh leech looking for food - the narrow end is the front.

 

Well, Hirudo medicinalis, to be specific, the European medical leech. Their use was
first described by Sushruta, the father of plastic surgery, all the way
back in 600 BC and they have been used to treat various ailments since
then. From medieval to early modern times, the medical leech was used to
remove blood from ones body and restore the balance of the "humours." While
this practice fell out of favor in the 1800s, medical leeches are now
making a comeback in plastic and reconstructive surgery.

The leech is held over the area of reimplantation, waiting for it to latch on.

But first, a little anatomy... Leeches have suckers at both the front and
rear of their body. The jaws up front have three rows of 100 teeth each,
enabling them to break the skin and gain entry to the vasculature. To do
this unannounced, a local anesthetic in the saliva renders the bite
painless. Once attached, each leech is capable of sucking approximately 15
ml of blood from its unknowing host. A vasodilator ensures increased blood
flow to the leech, and an anticoagulant, hirudin, prevents the blood from
clotting. In the hospital, what´s good for the leeches is good for our
patients. Leeches not only reduce blood coagulation in tissue grafts, they
also relieve venous pressure from pooling blood, and stimulate circulation
to reattached eyelids, lips, fingers, and ears.

 

Here are two happily feeding leeches.

Here in trauma, we frequently find ourselves in the care of patients who
need body parts surgically replanted. However, even when the arterial
system can be re- anastomosed by our microvascular surgeons, venous
obstruction remains one of the main causes of graft failure. It is in these
patients with swollen, replanted grafts that leeches and hirudotherapy come
to the rescue, sucking the swollen blood away. But not just any leech will
do. Leeches are a potential vector of blood-borne disease and should be
obtained from a medical supply company. The most commonly encountered
infectious agents from the leech intestinal tract are the Gram-negative
bacteria, Aeromonas hydrophila, Pseudomonas, and Vibrio. Patients should be
given prophylactic antibiotics that cover gram-negative bacteria such a
fluoroquinolones, thus ensuring a healthy and prosperous relationship.

1. Ernst E. Born to suck -- the return of the leech? Pain. 2008 Jul
15;137(2):235-6. Epub 2008 Mar 25.
2. Porschinsky et al. Clinical uses of the medicinal leech: a practical
review. J Postgrad Med. 2011 Jan-Mar;57(1):65-71.*

 

 

Thanks to Dr. George Singer for this post