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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 R elated 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 -Pyogenicorganisms - 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-suppurativeinfection 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 • Clellulitis Vs 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 • Cutaneousgangrene, 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
TETANUS Treatment: wound debridement, penicillin Muscle relaxants, ventilatory support Nutritional support Prophylaxis: wound care, antibiotics Human TIG in high risk ( un-immunized ) Commence active immunization ( T toxoid) Previously immunized- booster >10 years needs a booster dose booster <10 years- no treatment in low risk wounds