by Marcy E. Rosenfield (Moore)
Copyright © All rights reserved. No
part of this document may be reproduced without the expressed, written
consent of the author.
One of the more serious and fairly common health problem that occurs in rabbits is the development of an abscess. Abscesses can arise anywhere in the body; internal, soft tissue, reproductive, but the most debilitating and seemingly hardest to cure are abscesses that develop in the jaw, eye, and other areas of the head. The theory of abscess treatment revolved around the now disproven fact that the only way to successfully treat and cure these infections was by removing all purulence and the surrounding tissue, bone, teeth, sometimes one or both eyes (enucleation). In many cases, this is impossible to do without causing debilitating effects to the rabbit. However, administering penicillin G benzathine/ penicillin G procaine on a long- term basis using fairly low, well- tolerated doses has been extensively documented and proven to eradicate the abscess and all residual infection. Excellent results have been achieved and replicated countless times by veterinarians and other rabbit experts in the US, Canada and around the world.
History and Evolution of bicillin usage
I was introduced to Bicillin C-R®
(150K penicillin G benzathine & 150K penicillin G procaine 300,000
units/ ml, Wyeth- Ayerst) by Professor Theodore Vonieda (Dept. of
Neurobiology
at Northeastern Ohio Universities) in November 1986 at the Society of
Neuroscience
convention. His laboratory had been using the "human" form of the
antibiotic for treating postoperative infection in rabbits.
There are many veterinary pharmaceutical companies
that make this antibiotic combination for use in animals. The
more
commonly known "brand" names®
are:
Ambi-pen, Benza-pen, Benzapro, Bomacillin-LA, Combicillin-LA, Co-op,
Crystiben,
Dual-cillin, Duo-pen, Duplocillin, Durabiotic-LA, Dura-pen, Ethacillin,
Flo-cillin, Long Acting Penicillin, Longisil, PenPB- 48, Pen-Ben 48,
Pendure
Neat, Penject + B, Penlong XL, and Twin-pen. Because there is no
standard name for this antibiotic cocktail, I will use the name
"bicillin"
(small "b") for simplicity's sake.
In 1980's, our laboratory's research centered
on single cell unit recording in awake, behaving animals.
Postoperative
infection was common in rabbits who have undergone the surgical
procedure
for electrophysiological recording, which involved building and
cementing
a recording pedestal used to hold and stabilize the rabbit's head in
the
proper stereotaxic plane during these recording sessions. Most
rabbits
(two out of three) developed an infection either around the periphery
of
the recording pedestal or contracted septicemia through the
introduction
of bacteria during the recording procedure itself. These
complications
usually surfaced a week or more after the surgical procedure. The
post operative infection that began around the periphery of the
recording
pedestal would over time, penetrate and eat away at the bone, turning
it
to mush. Administering 0.25 cc of bicillin (approximately 75,000
units) every three days eradicated the infection after only one week of
treatment. Slowly the damaged bone regrew and was replaced by
healthy
bone. Not one rabbit experienced side effects, no disturbance of
the gut flora was noted with bicillin usage, even at higher doses (1.0
cc or 300,000 units per dose). From this time on, the use
of
bicillin became an integral part of the laboratory's surgical/
postoperative
protocol.
Treating Severe Chronic Infection/ Abscesses
All standard treatments begin with the removal
of the abscess and debriding the area. The more popular surgical
options used are removal of the eye (enucleation, removal of molar
spurs
or sometimes the tooth or teeth and then packing the abscessed cavity
with
calcium hydroxide, which has been reported to cause serious tissue
damage
and necrosis at the affected site, or packing the cavity with 50%
dextrose,
or packing the affected area with antibiotic impregnated polymethyl
methacrylate
beads (AIPMMA), a technique analagous to radioactive seeding used in
treating
prostate cancer in humans. Beads impregnated with an antibiotic
indicated
by culture and sensitivity are implanted in affected areas, allowing
the
slow release of the chosen antibiotic. Because the pus (purulent)
in rabbits is thick, almost the same consistency of mayonnaise and does
not drain, residual "fingers" of infection are usually left
behind.
These pockets of infection can lead to the formation of secondary
abscesses
from residual bacteria left in the vicinity of the main abscess,
allowing
infection to continue to spread. As systemic antibiotics go, the
most frequently and perhaps overprescribed drug used in treating
infection
in rabbits today is enrofloxacin (Baytril®,
Bayer Co.), oral and injectable. It is well- documented that
abscesses
contain a host of different bacteria, both aerobic and anaerobic.
Enrofloxacin is not active against anaerobic bacteria so administering
this antibiotic as a standard treatment for abscesses may allow the
proliferation
of these anaerobes. Therefore it was imperative to find a safe,
effective
antibiotic that does not cause side- effects in the patient.
Other
advantages of bicillin are that bicillin injections do not cause skin
irritation
or sores at the injection site and administering one injection every
other
day is easier on rabbit owners, most of whom have little or no
experience
with injections.
Protocol, Doses and Schedule of Administration
I had such success using bicillin for postoperative
infection that I began to experiment, using it for other causes of
infection
such as wounds caused by bites from fights. It wasn't until my
own
pet rabbit Pal, at age seven, developed a severe infection and
accompanying
abscess likely caused by a scratch to his upper eyelid by his
"mate".
This infection innovated most of the right side of his face, coming to
a head as 12 to 15 cc's of pus just above his right eye.
Because of the limited options and Pal's age,
I felt that draining the abscess and administering bicillin on a long-
term basis was the best initial approach for us. The other
treatment
options could always be employed later.
As much pus as possible was removed first
with hydrogen peroxide to break down the pus. Although hydrogen
peroxide
has been argued to be damaging to the wound, H2O2 turns this purulence
into liquid form that is easily suctioned from the area. After
debridement,
the abscess was flushed with a sterile saline + hydrogen peroxide
solution
and a final wash ending with a sterile isotonic saline
solution.
The incision was closed using New Skin (liquid bandage, Medtech®).
Pal then received 0.50 cc (150,000 units) of Bicillin C-R administered
every other day for eight weeks, then reduced to every third day for
four
weeks. After three months of continuous bicillin administration,
Pal was declared abscess- free, suffered no relapse (2.5 years) during
his lifetime and best of all kept his eye and his vision.
The bicillin protocol and accompanying dosing
schedule was based on Pal's, a seven year old New Zealand,
experience.
Because most rabbits with infections and accompanying pain lose weight
during their bout, and most bunny owners do not have scales that are
sufficient
to carefully monitor small increments of weight gain (grams), the dose
of bicillin has been divided into two groups for administration
purposes:
* Rabbits weighing LESS than 2.50 Kgs receive 75,000 units every
other day
* Rabbits weighing MORE than 2.50 Kgs receive 150,000 units every
other day
* Route of administration: subcutaneous injection
Because the initial 12 "clinical" patients
chosen for bicillin administration had undergone numerous surgeries and
treatments (three to 12 surgeries per rabbit) and none successfully
eradicated
the infection, bacterial cultures were considered irrelevant. All
veterinarians participating agreed that bicillin was their patient's
last
hope and chance.
The length of treatment depends on (a) the
age and health of the patient, (b) how long the patient has been ill,
(c)
how many different treatments & other antibiotics were used and (d)
how well the infection responds to bicillin. At this point
in time rabbits are being treated with bicillin using the same dosage
schedule
as Pal's -- eight weeks of bicillin given every other day, followed by
four weeks of administration every third day.
Most rabbits responded immediately to bicillin
injections, while others who had been chronically ill for some time
took
anywhere from three to six weeks of injections before any results were
seen. Therefore it is imperative to continue the bicillin therapy
and not discontinue administration too soon.
There were rabbits in which their abscesses
did not respond or continued to grow while receiving the dosage stated
in this paper. However, by increasing the administration
rate
from every- other- day to every day eradicated the abscess and
sparing these rabbits from serious surgical intervention such as
enucleation.
This discovery made it possible to successfully treat rabbits with
inoperable
abscesses using only bicillin. Most rabbits tolerated the
increase
in bicillin administration without experiencing side effects, but it is
recommended that rabbits with histories of gut problems, sensitivities
or gastrointestinal stasis be given probiotics as a preventative
measure.
In conclusion, the use of penicillin G
benzathine/
procaine used as a systemic antibiotic has successfully eradicated
abscess
and infection in rabbits without causing debilitating side effects that
other treatments tend to do. This has been proven countless times
by veterinarians who have independently replicated my results by
following
the protocol. It has also been proven that bicillin administered
as a primary antibiotic can prevent a small infection from becoming a
life-
threatening situation.
Other Considerations
Pain Management
A successful surgical preparation is based
on the recovery of the subject, that is how long it takes to recover
after
the surgical procedure back to pre- surgical condition and
behavior.
The most important aspect when dealing with rabbits is controlling
postoperative
pain. Without pain relief many rabbits stop eating, raising the
specter
of gastrointestinal stasis and other complications. Injecting a
minute
amount (0.25 cc - 0.50 cc) of lidocaine HCl (Xylocaine®
1% or 2%, Astra) epidermally at the area of the incision dramatically
decreases
postoperative pain caused by edema and swelling by interrupting the
cascading
effect caused by trauma to the affected area. Lidocaine applied
before
any surgical procedure anaesthetizes the area for up to four hours from
the initial injection time. Adding a local anesthetic to any pre-
surgical preparation is an inexpensive and simple way to help alleviate
or eliminate postoperative pain.
Acknowledgements
First and foremost I must thank Pat Franklin
who's bunny Londo was the first "clinical" patient to be successfully
treated
using this protocol. Pat not only helped kept me focused on our
quest
during some pretty strenuous times and was also instrumental in helping
many others whose bunnies were in the same dire straits. I also
want
to thank Dr. Anita Sabellico (Suffield Veterinary Hospital in Suffield
Connecticut), the first veterinarian willing to try bicillin on a "last
chance" bunny, Londo. Another big thank you goes to Christine
Goodhand,
her brave bunny Billy, her veterinarian Dr. Guy Carter who immediately
recognized bicillin's potential and Dr. Linda Dykes (president of the
BHRA)
for her featured article on bicillin in the BHRA journal "Rabbiting
On".
I also want to thank Marti Veneziale and her bunny Bubby the second
success
story, Primula Nevel for her proofreading expertise, and Bob
Polewan, Neuroscience doctoral student, UMass/ Amherst, for putting
this on the internet and making this data available to the public.
Linked to this protocol are a few of the hundred plus
cases, written in the bunny owner's "own words". Contributions to
this page are more than welcome and can be sent to the author.
The
data and subsequent results gathered can be used as an outline and
guide
for veterinarians interested in exploring the use of penicillin G
benzathine/
procaine for their rabbit- patients and the cases illustrated help
reassure
bunny owners that the diagnosis of an abscess no longer means chronic
illness,
debilitation, or certain death.
This protocol and accompanying data will be
revised and updated as more patients' case studies are reported.
Questions, queries, and case study contributions can be directed to the
author at petlabrabbits@webtv.net
Disclaimer: All data regarding bicillin was the accumulation of 15+ years of observation, data gathering and refinement. No abscess/ infection was induced, nor was any rabbit killed for any data associated with this work.
References
Small Animal Wound Management; ed. by Steven F. Swain, DVM, MS and
Ralph Henderson Jr., DVM, MS.; Lea and Febiger, Philadelphia-
London,
1990, pgs.12- 13, 46.
A Volumetric Study of Guided Bone Regeneration Around Titanium
Implants
in the New Zealand White Rabbit; G.L. Pal, A. Stephenson, I.J.
Klineberg,
M. Pearson, T. Albrektsson, C.
Johansson, Australian Dental Journal 1998; 43:(2): pgs. 73- 80.
Management of Abscesses of the Head in Rabbits; R. Avery Bennett, Veterinary Proceedings of the North American Veterinary Conference 1999, Vol. 13; pgs. 821- 823.
Wound and Abscess Management in Rabbits; Dr. Susan Kelleher, Exotic DVM, Vol. 2.3, June/ July 2000, pgs. 49- 51.
Ileus in Domestic Rabbit; D. Kremples, M. Cotter, and G. Stanzione; Exotic DVM, Vol. 2.4, August 2000.
Mandibular Abscess Treatment Using Antibiotic Impregnated Beads; Stephen J. Divers, Exotic DVM, Vol. 2.5, October/ November 2000.
"Hope in Fighting Abscesses", Christine Goodhand, Rabbiting On, Summer 2001, pp. 5.
"Rabbit Health Matters"; Dr. Linda Dykes MBBS (Hons) MRCSEd A&E and Veterinary Advisor Owen Davies, BVSc MRCVS; Rabbiting On, Summer 2001, pp.18- 20.
Periodontal Bacteria in Rabbit Mandibular and Maxillary Abscesses; K.L. Tyrell, D.M. Citron, J.R. Jenkins, E.J.C. Goldstein, and the Veterinary Study Group; Journal of Clinical Microbiology, March 2002; 40:(3): pgs. 1044- 1047.
Copyright © November 2000, revised December 2001, 3rd revision: December 2002