infectious diseases
Abscesses
Etiology of Abscesses
Numerous organisms can cause abscesses, but the most common is Staphylococcal Infections None Organisms may enter the tissue by Direct implantation (eg, penetrating trauma with a contaminated object) Spread from an established, contiguous infection Dissemination via lymphatic or hematogenous routes from a distant site Migration from a location where there are resident flora into an adjacent, normally sterile area because natural barriers are disrupted (eg, by perforation of an abdominal viscus causing an intra-abdominal abscess) Abscesses may begin in an area of Cellulitis or in compromised tissue where leukocytes accumulate. Progressive dissection by pus or necrosis of surrounding cells expands the abscess. Highly vascularized connective tissue may then surround the necrotic tissue, leukocytes, and debris to wall off the abscess and limit further spread. Predisposing factorsto abscess formation include the following: Impaired host defense mechanisms (eg, impaired leukocyte defenses) The presence of foreign bodies Obstruction to normal drainage (eg, in the urinary, biliary, or respiratory tracts) Tissue ischemia or necrosis Hematoma or excessive fluid accumulation in tissue Trauma 