Surgical infection Chapter one

Dr. Haydar Muneer

The Hippocratic teachings described theuse of anti-microbials, such as wine and vinegar, which werewidely used to irrigate open, infected wounds before delayedprimary or secondary wound closure

Risk factors for increased risk of wound infection■ Malnutrition (obesity, weight loss)■ Metabolic disease (diabetes, uraemia, jaundice)■ Immunosuppression (cancer, AIDS, steroids, chemotherapy and radiotherapy)■ Poor perfusion (systemic shock or local ischaemia)■ Foreign body material■ Poor surgical technique (dead space, haematoma)

■ Colonisation and translocation in the gastrointestinal tract

Classification of sources of infection1. Primary: acquired from a community or endogenous source (such as that following a perforated peptic ulcer)

2. Secondary or exogenous :acquired from the operating theatre (such as inadequate air filtration) or the ward (e.g. poor hand-washing compliance) or from contamination at or after surgery (such as an anastomotic leak)

Local and systemic presentation

Types of localized infection

1.Cellulitis

2.Abscess

Cellulitis Cellulitis is the non-suppurative invasive infection of tissues. There is poor localisation in addition to the cardinal signs of inflammation. Spreading infection presenting in surgical practice is typically caused by organisms such as

β-haemolytic streptococciSystemic signs are common: chills, fever and rigors. These follow the release of organisms, exotoxins and cytokines into the circulation. However, blood cultures are often negative.

AbscessPyogenic organisms, predominantly Staphylococcus aureus, cause tissue necrosis and suppuration. Pus is composed of dead and dying white blood cells that release damaging cytokines, oxygen free radicals and other molecules.

Granulation tissue forms later around the suppurative process and leads to collagen deposition. If it is not drained or resorbed completely, a chronic abscess may result. If it is partly sterilized with antibiotics, an Antibioma

Wound abscesses may discharge spontaneously by tracking to a surface, but may need drainage through a surgical incision. Most abscesses relating to surgical wounds take 7–10 days to form after surgery

Abscess cavities need cleaning out after incision and drainage and are encouraged to heal by secondary intention. All loculi need to be opened and curetted before resolution can occur

Stages of infection characteristic Cellulitis Abscess

Duration 3-7 days Over 5 days

Localization Diffuse Localized

Skin quality Reddened Peripherally reddened

Tissue fluid Serum, flack of pus Pus

Predominant bacteria

Mixed Anaerobic

Chronic AbscessCertain organisms are associated with chronicity, sinus and fistula formation. Common ones are Mycobacterium and Actinomyces They should not be forgotten when these complications occur.

ACTINOMYCOSISActinomycosis is a chronic, suppurative infection caused by a filamentous bacterium, usually Actinomyces israelii.

Bacteria causing actinomycosis are common in the normal mouth. Injuries, especially dental extractions or fractures of the jaw, can provide a pathway and sometimes precede infection but in fact, rarely do so. Most patients were previously healthy and it is uncommon even in patients with AIDS. The pathogenesis is therefore unclear.

Clinically, men are predominantly affected, typically between the ages of 30 and 60 years. A chronic soft tissue swelling near the angle of the jaw in the upper neck is the usual complaint unresponsive to conventional, short courses of antibiotics

The mainstay of treatment is penicillin, which should be continued for 4-6 weeks or occasionally longer.

Tuberculosis Is a chronic infectious disease caused by myobacterium tuberculosis

Primary tuberculousis occur in previously unexposed people and almost always involve the lung

Most infection result from direct person to person spread through airborn droplets

The most common extrapulmonary sites in the head and neck are cervical lymph node

If a tuberculous ('cold') abscess and sinus form, incision is contraindicated and affected nodes should be excised intact.

SYSTEMIC INFLAMMATORY RESPONSESepsis is defined as the systemic manifestation of SIRS, with a documented infection two of :

hyperthermia (> 38°C) or hypothermia (< 36°C)tachycardia (> 90 min–1, no β-blockers) or tachypnoea (> 20 min–1)

white cell count > 12000 or < 4000Hyperglycemia in the absence of diabetes

Specific wound infections

1.Gas gangrene

2.Clostridium tetani

3.Necrotizing fasciatis

Gas gangreneThis is caused by C. perfringens. These Gram-positive, anaerobic, spore-bearing bacilli are widely found in nature, particularly in soil and faeces.

Patients who are immunocompromised, diabetic or have malignant disease are at greater risk, particularly if they have wounds containing necrotic or foreign material, resulting in anaerobic conditions

Gas gangrene wound infections are associated with:

severe local wound pain and crepitus (gas in the tissues, which may also be noted on plain radiographs).

The wound produces a thin, brown, sweets melling exudate, in which Gram staining will reveal bacteria. Oedema and spreading gangrene follow the release of collagenase,hyaluronidase, other proteases and alpha toxin.

Clostridium tetaniAnaerobic, terminal spore-bearing, Gram-positive bacterium that can cause tetanus following implantation into tissues or a wound

The signs and symptoms of tetanus are mediated by the release of the exotoxin tetanospasmin, which affects myoneural junctions and the motor neurones of the anterior horn of the spinal cord

Treatment and prophylaxis will be discussed in the second chapter

Necrotizing FasciitisA mixed pattern of organisms is responsible: coliforms, staphylococci, Bacteroides spp., anaerobic streptococci and peptostreptococci have all been implicated, acting in synergy.

Patients are almost always immunocompromised with conditions such as diabetes mellitus.

Severe wound pain, signs of spreading inflammation with crepitus and smell are all signs of the infection spreading. Untreated, it will lead to widespread gangrene and MOF.

The subdermal spread of gangrene is always much more extensive than appears from initial examination. Broad-spectrum

antibiotic therapy must be combined with aggressive circulatory support. Locally, there should be wide excision of necrotictissue and laying open of affected areas.

What is the diagnosis and etiology and management

of ?

37 years male patient present to the emergency complaining from swelling in the right side of the face duration of 1 week Patient ( temp 39, WBC 12000) and give history of dental pain before the development of swelling ?