An abscess is a localized collection of pus. It contains necrotic tissue and suppuration from damage by the bacteria, and white blood cells. It is surrounded by area of inflamed tissue due to the body’s response to limit the infection. Pyogenic organisms, predominantly Staphylococci are the leading causes. These organisms lead to tissue necrosis and pus formation.
An abscess commences as a hard, red, painful swelling, which then softens and becomes fluctuant. If not drained, it may discharge spontaneously onto the surface or into an adjacent viscus or body cavity. There are the associated features of bacterial infection, namely a swinging fever, malaise, anorexia and sweating with a polymorph leucocytosis.
Patients with an abscess anywhere in the body may present with the following findings.
- Clinical features of inflammation when superficial (Heat, pain, edema, redness and loss of function) Local fluctuation if superficially located.
- Spontaneous discharge and sinus formation
- Systemic manifestations like fever, sweating, tachycardia
- Chronicity especially in granulomatous infection like mycobacteria,
Treatment of wound abscess
An established abscess in any situation requires drainage. Antimicrobial agents cannot diffuse in sufficient quantity to sterilize an abscess completely. Pus left undrained continues to act as a source of toxaemia and becomes surrounded by dense, fibrous tissue.
The technique of abscess drainage depends on the site. The classical method, which is applicable to a superficial abscess, is to wait until there is fluctuation and to insert the tip of a scalpel blade at this point. The track is widened by means of sinus forceps, which can be inserted without fear of damaging adjacent structures. If there is room, the surgeon’s finger can be used to explore the abscess cavity and break down undrained loculi. Drainage is then maintained until the abscess cavity heals – from below outwards – since otherwise the superficial layers can close over, with recurrence of the abscess. The cavity is therefore kept open by means of a gauze wick, a corrugated drain or a tube; the drain is gradually withdrawn until complete healing is achieved.
Deep abscesses can be localized and drained percutaneously using ultrasound or CT guidance.