Skin Abscesses
Esther van Praag Ph.D.
Warning: this page contains pictures that may be distressing for some persons.
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An abscess is a pocket of fluid and
pus, which results from an attack by pyogenic organism
(e.g., bacterium) followed by the destruction of cells. The pocket usually
contains a collection of pus, dead phagocytic white blood cells, necrotic
cells, and live or dead bacteria. As the quantity of pus increases, the
pocket grows larger and starts to wall off from the surrounding tissues and
blood circulation. This renders treatment difficult. If the abscess is left
untreated, it continues to grow. Tissue will rupture either inside the body
or on the surface of the skin. This stage is particularly painful and
dangerous, with the liberation of bacteria and their toxins in the blood
circulation. In
most cases of abscess, the rabbit has a history of pasteurellosis, though
other bacteria like Staphylococcus aureus, Streptococcus sp., Pseudomonas
sp or Fusiformis sp. are no exceptions. They
often result from a nasolacrimal or tooth problem,
surgery, insect bites, scratches or skin wound, trauma, or a foreign body
such as a hay splinter in the gum, foot sole or anal gland. Abscesses are typically found on the
head, neck and shoulders regions, but can also affect other parts of the
body, organs or bones. During palpation, abscesses feel either as a hard lump
or a soft doughy swelling that can be moved. The presence of an abscess is
usually painless, unlike other animals. It is often observed that abscesses
can grow within a few days time.
Clinical signs
There are no specific clinical signs,
except the presence of a lump, an unusual swelling, reduced appetite,
increased water intake, and/or fever.
Treatment
The treatment of an abscess is difficult,
long, and recurrence is no exception in rabbits. Use of systemic antibiotics
will have little effect and more aggressive therapy is needed. The best option remains total
surgical excision of the abscess cavity, necrotic tissue, and the surrounding
fibrous capsule. This treatment can, however, not be done when several
abscesses are present, or when the bone is affected (e.g., osteomyelitis, jaw
bone infection by a tooth root). During the surgical procedure, it is
important to check that no fibrous channels leading to abscess cavities
deeper in the tissue remain. If present, the cavities must be flushed with
antiseptic solutions (e.g., chlorhexiderm or iodine povidone) by means of a
catheter tube. A drain can be placed to facilitate this procedure. The cavity should be packed with an
antibiotic impregnated dressing. Various types are available nowadays
include: • Permanent placement of antibiotic impregnated PMMA beads; • Temporary filling with antibiotic impregnated gelatin or
cellulose hemostat (e.g., GelFoam®, Surgicel®). The dressing must be changed daily or every
2nd day, to avoid necrosis of surrounding tissues; • Temporary filling with wet-to-dry hygroscopic and bactericidal
sugar dressing (e.g., 50% dextrose, or manuka or clear sterilized (g-rayed) honey). The dressing must be
changed daily, to avoid necrosis of surrounding tissues. The later filling presents the
advantage to remove the malodorous smell of ammonium and sulfur compounds due
to bacterial breakdown of serum or cell proteins. If osteomyelitis (bone infection) has
developed, systemic administration of antibiotics is necessary. Antibiotics
of choice include those that penetrate the bone or joints, e.g.,
chloramphenicol, fluoroquinolone (enrofloxacin or marbofloxacin), bicillin (a combination of penicillin G benzathine and
penicillin G procaine), or penicillinase-resistant semi-synthetic penicillin
such as cephalosporin or metronidazole. The choice of antibiotics
safe for use in rabbit is limited.
The treatment needs to be aggressive
and long (4 to 6 weeks). If this antibiotic treatment is not successful, or
if large parts of the bone have been destructed, radical debridement remains
necessary. Nowadays, gentamycin PMMA beads can be implanted near the bone. There is little information is
available about the effusion rate of the antibiotic from antibiotic impregnated
gel sponge or beads. Newly grown tissue may hinder a good distribution of the
antibiotics from beads after 3 weeks already, limiting their action to 6
weeks. It should be kept in mind that
abscesses in rabbits are difficult to treat and a full recovery without
relapse cannot be guaranteed.
Acknowledgement
Thanks are due (listed alphabetically) to Dr. Orlando Diaz
(Lake Howell Animal Clinic, Maitland-FL, USA), and to Michel Gruaz (Switzerland) for the
gracious permission to use their pictures. Further
information
Aoyama
T, Sunakawa K, Iwata S, Takeuchi Y, Fujii R. Efficacy of short-term treatment of pertussis with clarithromycin
and azithromycin. J Pediatr.
1996; 129(5):761-4. Blackwell
NJ. Abscesses in rabbits. Vet Rec. 1999; 144(19):540. Harcourt-Brown
F. Rabbit Medicine and Surgery, Oxford, UK: Butterworth-Heinemann 2001, 192
pages. Hillyer EV, Quesenberry
QE. Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery New York: WB
Saunders Co.,1997. Ladefoged O. The
absorption half-life, volume of distribution and elimination half-life of
trimethoprim after peroral administration to
febrile rabbits. Zentralbl Veterinarmed
A. 1979; 26(7):580-6. Ladefoged O. Pharmacokinetics of
trimethoprim (TMP) in normal and febrile rabbits. Acta
Pharmacol Toxicol (Copenh). 1977; 41(5):507-14. Bergman
A, Yanai J, Weiss J, Bell D, David MP. Acceleration
of wound healing by topical application of honey. An animal model. Am J Surg.
1983; 145(3):374-6. [No
authors listed] Related Extraction and abscess treatment in a rabbit. J Vet
Dent. 2000; 17(2):95. Richardson
V. Rabbits: Health, Husbandry and Disease. Blackwell Science Inc, 2000. |
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