Treatment of abscesses
An abscess is a pocket of pus within tissue. They form due to an inflammatory reaction to bacteria or foreign substance in the area. In tigers, abscesses are commonly seen secondary to bite wounds, claw wounds and trauma
The clinical signs of an abscess are swelling, increased heat in the affected area, redness and hair loss in the abscess. Abscesses are painful so the tiger may be paying attention to the affected area (e.g. by overgrooming) or not be using the affected area normally. Sometimes abscess may only be evident when they rupture.
The diagnosis of an abscess in a tiger may need to be made without actually manually examining the area. If the tiger is anaesthetised for an examination an abscess can be diagnosed by palpating the affected swollen area, seeing the redness and feeling the increased temperature of the affected skin and by aspirating purulent material from the area. Wherever possible purulent material from an abscess should be collected on a charcoal swab and submitted to a laboratory for culture and sensitivity. It is important to ensure that the swab only contacts the pus and not other surrounding tissue/ objects. When submitting the swab for culture it is prudent to include a list of appropriate antibiotics for the laboratory to run the sensitivity testing against. An appropriate list should be assembled according to product availability and suitability for dosing in tigers (see formulary).
The treatment of an abscess in a tiger depends on the location, demeanour of the tiger and whether it has ruptured.
Abscesses that have ruptured should not require antibiotic treatment. They often resolve without treatment but, if necessary, they should be expressed and flushed. This involves flushing the abscess with appropriate diluted antiseptic such as diluted chlorhexidine (0.05%), diluted F10 (1:250) or diluted iodine (10%). If the tiger has been anesthetised to achieve the fur surrounding the area should be clipped and the skin cleaned with the same dilute antiseptic agent used as a skin scrub. A water-based lubricant (such as KY jelly) should be applied into the ruptured abscess and any surrounding wounds before the surrounding fur is clipped. The lubricant traps any resulting fur and dirt, preventing any further contamination to the area. If the abscess is found to have a very small drainage hole this can be enlarged using a sterile scalpel (see below).
Abscesses that have not ruptured may need lancing. All fur surrounding and on the abscess should be clipped away and the skin prepared with antiseptic skin scrub as above. The abscess should be lanced with a sterile scalpel ensuring if possible that that resulting drainage hole will face ventrally when the tiger is awake, ensuring continuing drainage. The size of the drainage hole will depend on the size of the abscess but a large drainage hole of 2-3cm is desirable. After lancing the abscess should be flushed as above. Most abscesses that are lanced in this way also do not require antibiotics.
Occasionally an abscess may need antibiotic treatment. This is usually seen in debilitated animals, animals with co-morbidities or where the bacteria in the abscess are very pathogenic (e.g. Pasteurella). In these cases, the redness around the abscess will start to spread, along with the associated swelling. The tiger is likely to become more lethargic and eat less. Antibiotic treatment should be based on culture and sensitivity obtained from the abscess. Even more occasionally, an abscess can cause a systemic infection/ septicaemia in a tiger. In these cases, the tiger will begin to look increasingly unwell with signs such as lethargy, decreased appetite, rapid breathing and vomiting/ diarrhoea. In these cases, intravenous antibiotic therapy and supportive intravenous fluids may be needed.
Tiger with paw abscess forming on distal forelimb
Tiger with fur clipped around abscess to allow treatment