Abscesses are collections of pus in confined tissue spaces, usually caused by a bacterial infection. Symptoms include local pain, tenderness, flushing and swelling (when located near the skin layer) or constitutional symptoms (if found deep within). Imaging studies are sometimes necessary to diagnose deep abscesses. Treatment is surgical drainage and often antibiotics .
Etiology
Many microorganisms can cause abscesses , although the most common is Staphylococcus aureus.
Microorganisms can enter tissue by:
• Direct implantation (eg, from penetrating trauma with a contaminated object).
• Spread from a contiguous established infection site.
• Spread by lymphatic or hematogenous routes from a distant site.
• Migrating from a place where there resident flora towards a normally sterile site adjacent, due to the disruption of the natural barriers (p. G., A perforation that causes intraabdominal abscess abdominal viscera).
Abscesses can form in an area of cellulite or in compromised tissue where white blood cells accumulate. Progressive dissection caused by pus or by necrosis of surrounding cells expands the abscess. Highly vascularized connective tissue can then surround necrotic tissue , leukocytes, and cellular debris, forming a wall that delimits the abscess and prevents it from spreading further.
Predisposing factors
Altered host defense mechanisms (eg, decreased leukocyte defenses)
• The presence of foreign bodies.
• Obstruction of normal drainage (eg, in the urinary tract, respiratory biliary).
• Ischemia or tissue necrosis.
• Hematoma or excessive accumulation of fluid in the tissue.
• Trauma .
Signs and symptoms
Signs and symptoms of skin and subcutaneous abscesses are pain, warmth, swelling, tenderness, and redness. If the superficial abscesses are about to rupture spontaneously, the skin over its central part may be thin, sometimes with a white or yellowish appearance due to the presence of pus under it (with the appearance of a point). Fever may appear, especially with surrounding cellulite. In deep abscesses, local pain and tenderness, and systemic symptoms, especially fever , as well as anorexia , weight loss, and fatigue are typical . The predominant manifestation of some abscesses is abnormal organ function (eg, hemiplegia due to a brain abscess).
Complications
• Bacteremic spread.
• Break in adjacent tissue.
• Bleeding from vessels eroded by inflammation.
• Alteration of the function of a vital organ.
• Starvation due to anorexia and increased metabolic needs.
Diagnosis
• Clinical evaluation.
• Sometimes ultrasound, CT, or MRI.
Diagnosis of skin and subcutaneous abscesses is made by physical examination. Diagnosis of deep abscesses often requires imaging techniques. Ultrasound is noninvasive and detects many soft tissue abscesses ; CT is accurate for most cases, although MRI is usually more sensitive.
Treatment
• Surgical drainage.
• Sometimes antibiotics.
Superficial abscesses can be resolved with the application of heat and oral antibiotics. However, its disappearance usually requires drainage. Minor skin abscesses may require only one incision and one drain. All pus, necrotic tissue, and debris should be removed. Removal of the open (dead) space with gauze packing or placement of drains may be necessary to prevent recurrence of the abscess. Predisposing factors, such as obstruction of a natural drainage or the presence of a foreign body, must be corrected. Deep abscesses can sometimes be adequately drained with percutaneous needle aspiration (usually ultrasound or CT-guided); This method often avoids the need for an open surgical drain.Spontaneous rupture and drainage can occur, sometimes leading to the formation of chronic drainage paths. Without drainage, an abscess sometimes resolves slowly after proteolytic digestion of pus, which creates a thin, sterile fluid that is reabsorbed into the bloodstream. Incomplete reabsorption can produce a cystic loculation with a fibrous wall that is susceptible to calcification.
Systemic antimicrobials are indicated as adjunctive therapy as follows: • If the abscess is deep (eg, intra-abdominal).
• If there are multiple abscesses.
• If there is a significant surrounding cellulite .
• Maybe if the size is> 2cm.
Antimicrobial drugs are generally ineffective without drainage. Empirical antimicrobial therapy is based on the location and likely pathogen causing the infection. Subsequent therapy should be guided by Gram stain, culture, and microbial susceptibility testing.