Surgical Infections

Lesson Objectives

By the end of this topic, learners should be able to:

1. Define key surgical infections and their pathophysiology.

2. Recognize clinical features and complications of surgical infections.

3. Understand principles of antibiotic therapy and surgical intervention.

4. Apply nursing and medical principles in prevention and management.

 Key Glossary Terms

1. Surgical Site Infection (SSI)

• Definition: Infection occurring within 30 days of surgery (or 90 days if prosthetic implant), affecting incision or deep tissue.

• Types:

  • Superficial incisional

  • Deep incisional

  • Organ/space infection

• Prevention: Aseptic technique, prophylactic antibiotics, sterile dressings.

2. Abscess

• Definition: Localized collection of pus within tissue.

• Clinical Features: Pain, swelling, erythema, fluctuant mass, fever.

• Management: Incision and drainage, antibiotics if systemic infection.

3. Cellulitis

• Definition: Infection of skin and subcutaneous tissue without pus collection.

• Clinical Features: Red, warm, tender, swollen area; systemic symptoms possible.

• Management: Systemic antibiotics, elevation, wound care.

4. Necrotizing Fasciitis

• Definition: Rapidly progressive infection of fascia with necrosis of subcutaneous tissue.

• Clinical Features: Severe pain, erythema, swelling, skin discoloration, crepitus, systemic toxicity.

• Management: Surgical debridement (emergency), broad-spectrum IV antibiotics, supportive care.

• Mnemonic: “Pain out of proportion to exam” → early warning sign.

5. Gas Gangrene (Clostridial Myonecrosis)

• Definition: Muscle tissue infection by Clostridium species producing gas.

• Clinical Features: Severe pain, swelling, crepitus, foul-smelling discharge, systemic toxicity.

• Management: Emergency surgical debridement, high-dose IV antibiotics, hyperbaric oxygen therapy.

6. Post-Operative Fever

• Definition: Fever occurring after surgery (>38°C).

• Timing Mnemonic (5 W’s):

  • Wind (1–2 days) → Atelectasis/pneumonia

  • Water (3–5 days) → UTI

  • Wound (5–7 days) → SSI

  • Walking (5–7 days) → DVT/PE

  • Wonder drugs → Drug fever

7. Antibiotic Therapy in Surgical Infections

• Empiric Therapy: Broad-spectrum coverage (before culture results).

• Definitive Therapy: Based on culture & sensitivity.

• Common Classes:

  • Beta-lactams (e.g., amoxicillin-clavulanate)

  • Cephalosporins

  • Clindamycin for anaerobes

  • Vancomycin for MRSA

8. Principles of Surgical Infection Management

1. Source Control: Drain abscesses, debride necrotic tissue.

2. Antibiotics: Empiric → targeted therapy.

3. Supportive Care: Fluids, analgesics, nutrition.

4. Prevention: Hand hygiene, aseptic technique, prophylactic antibiotics when indicated.

9. Nursing & Medical Student Focus

• Nursing: Monitor for early signs of infection, wound care, patient education, administer antibiotics.

• Medical Students: Diagnose infection type, order cultures, plan surgical and medical management, monitor response.

 Tables

Table 1: Common Surgical Infections

Table 2: 5 W’s of Post-Operative Fever