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SURGICAL INFECTIONS. Begashaw M (MD). Surgical infection. D efined as an infection related to or complicating a surgical therapy and requiring surgical management Related to surgical therapy but may not require surgery - UTI after catheterization Pulmonary CXN after intubation
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SURGICAL INFECTIONS Begashaw M (MD)
Surgical infection • Defined as aninfection related to or complicating a surgical therapy and requiring surgical management • Related to surgical therapy but may not require surgery - UTI after catheterization • Pulmonary CXN after intubation • Tracheotomy site infection • Post-operative wound infection
CLASSIFICATION • Pre operative infections:before a surgical procedure - Accidents - Appendicitis - Boils - Carbuncle - Pyomyositis
Operative infections Happen during a surgical procedure Due to -contamination of the site -poor tissue handling
Postoperative infections Occur after a surgical procedure Contamination is from the patient’s source e.g - Surgical wound infections - Urinary & respiratory tract infection
PATHOGENESIS • Elements or factors include: - An infectious agent - A susceptible host - Favorable external factors/ environment
Infectious agents 1- Aerobic bacteria - Staphylococcus aureus - Streptococci - Klebsiella - E. coli 2- Anaerobic bacteria - Bacteroides - Peptostreptococci - Clostridia
Infectious agents 3- Fungi - Histoplasma - Candida - Nocardia and actinomycetes 4- Parasites - Entamebahystolytica-amebic liver abscess - Echinococcus - hydatid cyst
Host Susceptibility • Reduced immunity/host defense -Diabetes mellitus -TB -AIDS
Local and external factors • Local factors - Poor vascularization - Poor perfusion of blood and oxygen - Dead tissue - Foreign bodies - Closure under tension • External factors-break in the sterility technique
Clinical manifestation Hotness, redness, edema/swelling,pain & loss of function Non-Specific symptoms- Fever, chills, tachycardia Constitutionalsymptoms - Fatigue, low-grade fever
Investigations WBC count: usually elevated Gram stain ,culture & sensitivity Blood culture:bacterermia Biopsy: Histologic X-ray and ultrasound
Post-Operative Wound Infection Is contamination of a surgical wound during or after a surgical procedure Is usually confined superficial Below the fascia - deep infection
Source of infection 80% cases - patient (Endogenous) -skin ,transected viscus. In about 20% cases - Exogenous -environment -operating staff -unsterile surgical equipment
Clinical Findings • On the 5th-7thpostoperativeday - Fever - Wound pain - Wound edema and induration - Local hotness and tenderness - Wound/stitch abscess - Serous discharge - Crepitation
Management - Remove stitches to allow drainage - Local wound care - Antibiotics-if systemic manifestations/cellulitis
Prevention Shorten preop. Hospitalization Loose weight Treatment of remote infection Shorten operative time Restore host defense Decrease endogenous bacterial cont. Good surgical technique Proper asepsis and antisepsis Chemoprophylaxis
Abscess Localized collection of pus Contains necrotic tissue & suppuration Etiology -Pyogenic organisms - staphylococci
Clinical features - Superficial (Hot, pain, edema, rednessand loss of function) - Fluctuation - Discharge & sinus - Systemic - fever, sweating, tachycardia
Treatment - Drainage byincision - Debridement & curettage - Delayed primary or secondary closure - Antibiotics - systemic symptoms or signs of spread occur-cloxacillin
Erysipelas _ Acute skin infection that is more superficial than cellulitis _ Etiology - Group A Streptococcus (GABHS) _Clinical Features Intense erythema, induration, & sharply demarcated borders _Treatment - penicillin or first generation cephalosporin - cephalexin
Cellulitis • Non-suppurative infection of skin and subcutaneous tissues • Usually involves the extremities • Identifiable portal of entry • Etiology: skin flora - Beta hemolytic streptococci - Staphylococci - Clostridium perfringens
Clinical Features Source of infection -trauma, recent surgery -diabetes - cracked skin -foreign bodies Systemic - fever, chills, malaise Pain, tenderness, edema, erythema with poorly defined margins
Investigation • CBC, blood cultures • Culture and Gram stain • Plain radiographs- R/o osteomyelitis • CellulitisVs Eryspela -Cellulitis: indistinct border -Erysipela: sharp boarder
Management - Rest - Elevation/immobilize - Hot, wet pack - High dose broad spectrum antibiotics IV _Cloxacillin 500 mg QID/cephalexin
Pyomyositis • Acute bacterial infection of skeletal muscles with accumulation of pus inthe intramuscular area • Occurs in the lower limbs &trunk • Associated factors-Poor nutrition -immune deficiency -hot climate -intense muscle activity
Etiology -Staphylococcus aureus - common -Streptococci
Clinical Features • Sub-acute onset • Localized muscle pain & swelling • Tenderness • Induration, erythema, heat • Muscle necrosis • Fever
Treatment • Intravenous antibiotics- cloxacillin • Surgical drainage • Excision -necrotic muscle • Supportive care-analgesics
Necrotizing fasciitis • Rapidly spreading, very painful infection of the deep fascia with necrosis of tissues • Some bacteria create gas that can be felt as crepitus • Infection spreads rapidly along deep fascial plane and is limb and life threatening
Etiology • Polymicrobial - Streptococci- hemolytic - Staphylococci - Gram negative bacteria - Anaerobes - Clostridia
Clinical Features Pain out of proportion Erythema, edema, tenderness, ± crepitus ±fever Infection spreads very rapidly Rapidly become very sick/toxic Skin turns dusky blue and black (secondary to thrombosis & necrosis) Induration, formation of bullae Cutaneous gangrene, subcutaneous emphysema
Treatment Rigorous resuscitation Multiple surgical debridement: remove all necrotic tissue, copious irrigation IV antibiotics-Ceftriaxone +Metronidazole
Gas Gangrene Characterized by muscle necrosis and systemic toxicity Follows - Trauma - Surgery - Foreign bodies - Vascular insufficiency
Etiology -Clostridium perfringens -80% of cases - polymicrobial infection
Clinical features - Sudden and persistent severe pain at wound site - Localized tense edema, pallor , tenderness - Gas noted on palpation or radiograph - brownish discoloration of skin and hemorrhagic bullae - Dirty brown discharge with offensive, sweetish odor - Systemic - fever, tachycardia,hypotension
Management • Surgery - important -Extensive, wide excision -Amputation -Antibiotic -Supportive - Intravenous infusions - Blood transfusions - Close monitoring
TETANUS Cl. Tetani, produce neurotoxin Penetrating wound ( rusty nail, thorn ) Usually wound healed when symptoms appear Incubation period: 7-10 days Trismus - first symptom, stiffness in neck & back Anxious look with mouth drawn up ( risussardonicus) Respiration & swallowing progressively difficult Reflex convulsions along with tonic spasm Death by exhaustion, aspiration or asphyxiation