Infection of Open Wound

Overview

Wound infections are a common complication that can occur when the protective barrier of the skin is broken, allowing bacteria and other pathogens to enter the body. While the body has natural defense mechanisms to prevent infection, certain factors can overwhelm these defenses, leading to bacterial colonization and infection of the wound site.

Infections can develop in any type of open wound, including surgical incisions, traumatic injuries, burns, pressure sores, and chronic ulcers. The severity can range from superficial infections affecting only the skin surface to deep infections involving underlying tissues, muscles, or bones. Without proper treatment, wound infections can lead to serious complications including sepsis, tissue necrosis, and even death.

The incidence of wound infections varies depending on the type of wound and setting. Surgical site infections occur in 2-5% of clean surgeries and up to 20% in contaminated surgeries. Traumatic wound infections are even more common, particularly in wounds contaminated with soil, foreign bodies, or those with significant tissue damage. Understanding the signs of infection and implementing proper wound care is essential for optimal healing outcomes.

Symptoms

Recognizing the signs and symptoms of wound infection early is crucial for prompt treatment and prevention of complications. Symptoms typically develop 2-7 days after the initial injury but can occur at any time during the healing process.

Local Signs of Infection

• Abnormal appearing skin around the wound - increased redness, warmth, and discoloration
• Increased pain or tenderness at the wound site
• Swelling that worsens or doesn't improve
• Pus or cloudy drainage from the wound
• Foul odor from the wound
• Red streaks extending from the wound (lymphangitis)
• Wound edges separating or wound breakdown
• Delayed or stopped healing

Regional Symptoms

• Hand or finger swelling - if wound is on extremity
• Leg pain - for lower extremity wounds
• Swollen lymph nodes near the wound
• Limited mobility of affected area
• Numbness or tingling around wound

Systemic Signs of Infection

• Fever (temperature above 100.4°F or 38°C)
• Chills and sweating
• Insomnia due to pain or discomfort
• General malaise and fatigue
• Nausea or vomiting
• Rapid heart rate
• Confusion (in severe cases)

The presence of systemic symptoms often indicates that the infection has spread beyond the local wound site and requires immediate medical attention. Early infections may present with only local symptoms, while advanced infections typically show both local and systemic signs.

Causes

Wound infections are caused by the invasion and multiplication of microorganisms in damaged tissue. While bacteria are the most common culprits, other pathogens can also cause infections.

Common Bacterial Causes

• Staphylococcus aureus: Most common cause, including MRSA (methicillin-resistant strains)
• Streptococcus pyogenes: Causes rapidly spreading infections
• Pseudomonas aeruginosa: Common in burns and chronic wounds
• Escherichia coli: Often in abdominal or perineal wounds
• Enterococcus species: Hospital-acquired infections
• Clostridium species: Causes gas gangrene in deep wounds

Sources of Contamination

• Environmental contamination: Soil, water, foreign bodies
• Skin flora: Normal bacteria on skin surface
• Healthcare-associated: Contaminated instruments or poor hygiene
• Cross-contamination: From other infected sites
• Airborne particles: In surgical settings

Factors Promoting Infection

• Presence of dead tissue (necrosis)
• Foreign bodies in the wound
• Poor blood supply to the area
• Hematoma or seroma formation
• Wound tension or movement
• Excessive moisture or dryness

Risk Factors

Certain conditions and factors increase the likelihood of developing a wound infection. Understanding these helps identify high-risk patients who need extra vigilance.

Host Factors

• Diabetes: Impairs immune function and wound healing
• Advanced age: Decreased immune response and skin integrity
• Obesity: Poor tissue perfusion and increased wound tension
• Malnutrition: Impaired healing and immune function
• Immunosuppression: From disease or medications
• Smoking: Reduces tissue oxygenation
• Chronic diseases: Kidney, liver, or heart disease

Wound Characteristics

• Contaminated or dirty wounds
• Deep puncture wounds
• Wounds with tissue loss
• Crush injuries
• Bite wounds
• Wounds older than 6 hours before treatment
• Wounds in areas with poor circulation

Treatment-Related Factors

• Inadequate wound cleaning
• Improper surgical technique
• Long operative times
• Use of drains
• Emergency procedures
• Multiple wound dressing changes

Diagnosis

Diagnosis of wound infection is primarily clinical, based on signs and symptoms, but laboratory tests can help identify the causative organism and guide treatment.

Clinical Assessment

• Visual inspection: Examining wound appearance, drainage, surrounding tissue
• Palpation: Checking for warmth, tenderness, fluctuance
• Measurement: Documenting wound size and depth
• Photography: For monitoring progression
• Assessment of healing: Evaluating granulation tissue

Laboratory Tests

• Wound culture: Gold standard for identifying pathogens
  • Swab culture (superficial infections)
  • Tissue biopsy (deep infections)
  • Aspiration of pus
• Blood tests:
  • Complete blood count (elevated WBC)
  • C-reactive protein (CRP)
  • Erythrocyte sedimentation rate (ESR)
  • Blood cultures (if systemic infection suspected)
• Gram stain: Rapid identification of bacteria type

Imaging Studies

• X-ray: To check for foreign bodies or gas in tissues
• Ultrasound: Detects fluid collections or abscesses
• CT scan: For deep infections or complications
• MRI: Best for soft tissue and bone involvement

Treatment Options

Treatment of wound infections requires a comprehensive approach combining systemic therapy, local wound care, and addressing underlying factors that impair healing.

Antibiotic Therapy

Topical Antibiotics

• Mupirocin: Effective against Staph and Strep
• Silver sulfadiazine: For burns and large wounds
• Bacitracin/Polymyxin: Minor superficial infections
• Honey-based dressings: Natural antimicrobial properties

Oral Antibiotics

• First-line: Cephalexin, dicloxacillin
• MRSA coverage: Trimethoprim-sulfamethoxazole, doxycycline
• Broad spectrum: Amoxicillin-clavulanate
• Duration: Usually 7-14 days depending on severity

Intravenous Antibiotics

• Reserved for severe infections
• Vancomycin for MRSA
• Piperacillin-tazobactam for broad coverage
• May require hospitalization

Wound Care

• Cleansing: Saline irrigation, removal of debris
• Debridement: Removal of dead tissue
  • Surgical debridement
  • Enzymatic debridement
  • Autolytic debridement
• Drainage: Of abscesses or fluid collections
• Dressing selection:
  • Absorptive dressings for exudate
  • Antimicrobial dressings
  • Moisture-retentive dressings

Surgical Intervention

• Incision and drainage of abscesses
• Exploration and washout of deep infections
• Removal of infected foreign bodies
• Tissue reconstruction after infection control
• Amputation in severe cases

Supportive Care

• Pain management: Analgesics as needed
• Elevation: Of affected extremity to reduce swelling
• Immobilization: To promote healing
• Nutritional support: Protein and vitamin supplementation
• Blood sugar control: In diabetic patients
• Tetanus prophylaxis: If indicated

Prevention

Preventing wound infections is more effective than treating established infections. Prevention strategies should begin immediately after injury and continue throughout healing.

Immediate Wound Care

• Clean wounds thoroughly within 6 hours of injury
• Remove all foreign material and debris
• Irrigate with saline or clean water
• Avoid hydrogen peroxide or alcohol on open wounds
• Apply appropriate dressing

Ongoing Care

• Keep wound clean and dry
• Change dressings as directed
• Wash hands before and after wound care
• Monitor for signs of infection
• Complete prescribed antibiotics
• Avoid touching or picking at wounds

Risk Reduction

• Control underlying medical conditions
• Optimize nutrition
• Stop smoking
• Maintain good hygiene
• Update tetanus vaccination
• Seek prompt medical attention for high-risk wounds

Healthcare Settings

• Strict aseptic technique
• Appropriate surgical prophylaxis
• Minimize operative time
• Proper sterilization of instruments
• Hand hygiene compliance

When to See a Doctor

While minor wounds can often be managed at home, certain situations require professional medical evaluation to prevent serious complications.

Seek Immediate Medical Attention For:

• Signs of spreading infection (red streaks, fever, chills)
• Rapidly worsening pain or swelling
• Pus or foul-smelling drainage
• Wounds that won't stop bleeding
• Deep or gaping wounds
• Wounds with visible fat, muscle, or bone
• Animal or human bites
• Puncture wounds, especially on feet
• Wounds contaminated with dirt or debris you can't remove

Schedule an Appointment If:

• Wound isn't healing after 24-48 hours
• Increasing redness around wound
• New drainage from wound
• Sutures or staples become loose
• You have diabetes or poor circulation
• Last tetanus shot was over 10 years ago

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