Surgical Infections - الأهلية

Surgical Infections

• Wound infections, also called surgical site infections, involve the invasion of organisms into tissues
• This follows a breakdown of local and systemic host defenses, leading to conditions like cellulitis, lymphangitis, abscess, and bacteremia

Sources of Infection

• Primary infections are acquired from a community or are from an endogenous source, e.g., a perforated peptic ulcer.
• Secondary infections follow surgery and can be hospital-acquired, termed healthcare-associated infections, or HAI
• HAIs can originate from the operating theatre due to inadequate air filtration, the ward due to poor hand-washing compliance, or contamination during or after surgery such as an anastomotic leak.

Main Groups of HAI

• Respiratory infections, including ventilator-associated pneumonia
• Urinary tract infections mostly related to urinary catheters
• Bacteremia mostly related to indwelling vascular catheters
• Surgical Site Infections (SSIs)

Reduced Host Resistance

• Reduce host resistance with Metabolic factors like malnutrition including obesity, diabetes, uremia, and jaundice
• Disseminated diseases like cancer and AIDS also decrease resistance
• Iatrogenic causes, such as radiotherapy, chemotherapy, and steroids, can lead to reduced host resistance to infection

Complications of Surgical Infections

• Bacteremia is the transient circulation of bacteria in the blood, is usually asymptomatic
• Toxemia involves endotoxins and exotoxins circulating in the blood, which can initiate a systemic body response
• SIRS, or Systemic Inflammatory Response Syndrome, which is an inflammatory state affecting the whole body in response to severe infectious incidents.
• Sepsis, or septicemia, which is a severe infection associated with SIRS
• Severe sepsis is severe infection associated with SIRS and MODS, or Multiple Organ Dysfunction Syndrome
• Septic shock is sepsis with cardiovascular collapse and shock

Pathogenesis

• Pathogens resist host defenses by releasing toxins, which can promote their spread
• This is especially true in anaerobic or necrotic wound tissue
• Resistance to antibiotics can be acquired by previously sensitive bacteria
• The human body harbors over 1000 organisms
• Microbes get released into tissues by surgery, contamination is most severe when a hollow viscus perforates such as in fecal peritonitis

Risk Factors

• Malnutrition: obesity or weight loss
• Metabolic disease: diabetes, uremia, or jaundice
• Immunosuppression: cancer, AIDS, steroids, chemotherapy, or radiotherapy
• Poor perfusion: systemic shock or local ischemia
• Foreign body material
• Poor surgical technique such as causing dead space or hematoma

Classification

• According to Depth:
  • Superficial surgical site infection: SSSI
  • Deep SSI in deeper musculofascial layers
  • Organ space infection, e.g., abdominal abscess
• According to Severity:
  • Minor SSI
  • Major SSI
• According to Cleaning:
  • Clean: No inflammation and sterile technique maintained
  • Clean-Contaminated: Respiratory, alimentary, or genitourinary tract entered under controlled conditions
  • Contaminated: Major break in sterile technique or gross spillage from the gastrointestinal tract
  • Dirty or Infected: Viscera perforated or acute inflammation with pus encountered

Clinical Picture

• Major Wound Infection:
  • Significant pus discharge
  • Secondary drainage procedure needed
  • Systemic signs present like tachycardia, pyrexia, raised white count
• Minor Wound Infection:
  • Pus or infected serous fluid discharge
  • No excessive discomfort
  • No systemic manifestation
  • Can be managed at home

Southampton Scoring System

• 0: Normal healing
• I: Normal healing with mild bruising or erythema
• II: Erythema plus other signs of inflammation
• III: Clear or serosanguinous discharge
• IV: Pus
• V: Deep or severe wound infection with/without tissue breakdown
• Hematoma requiring aspiration
• Grades IV and V are considered major SSI

Surgical Site Infections

• Prophylaxis with antibiotic, and treatment, are crucial aspects
• Abscesses form in in 7-10 days after surgery
• Patients are typically diagnosed at follow-up clinics

Prophylaxis

• Optimize condition in the preoperative stage
• Preoperative shaving should be avoided to prevent infections
• Staff must always wash their hands
• Postoperative:
  • Ensure proper Oxygenation in recovery
  • Prophylactic antibiotics at induction of anesthesia, repeated every 6-8 hours if long operation
  • Keep length of stay minimum
  • Postoperative wound care
• Antibiotic use rationale:
  • There is a delay before the body protects the wound
  • The inflammation subsides in four hours
  • Calling this the 'decisive period', indicating when bacteria tries to invade
  • Antibiotics must be given during this period

Antibiotics

• Use empirical cover & single-shot, repeating if excessive bleeding, stop if clean
• Benzylpenicillin is needed if you suspect Clostridium
• Give patients undergoing surgery antibiotics during dental work

Definitive Treatment

• Suture removal performed with culture and sensitivity
• Use broad-spectrum until the culture tests are conclusive
• Treatment of the cause
• Treat any septic shock

Cellulitis

• Caused by spreading inflammation of tissues
• Occurs under the skin, but can spread
• Bacteria is B-hemolytic group A
• Hyaluronidase and Streptokinase help invade

Diagnosing Cellulitis

• Skin is red and hot
• Skin will blanch
• Painful
• Can have gangrene
• Mimics Lymphangitis:
  • Lymph Will feel swollen
  • Nodes affected

Treatment for Cellulitis

• Elevation and antibiotics
• Monitor for necrotizing effects

Abscess

• An abscess is a localized collection of pus coming from organisms
• Pyogenic organisms, Staphylococcus aureus, cause tissue necrosis
• Pus:
  • WBCs release toxins
  • An abscess is an inflammatory response
  • Membrane forms
  • Granulation, then collagen deposited
• If abscess is not drained, it can become chronic

Describing Abscess

• Swollen and painful
• Softens and fluctuates
• If not drained, it can leak
• Bacteria causes infection
• Patient will be feverish
• Clinically diagnose with:
  • CBC and ESR tests to check infection levels
  • US, CT or MRI scans

Treatment for Abscess

• Drain the pus, this is the ONLY treatment
• Drain any infection that is spreading
• NEVER wait if it is a Parotid, Breast, Hand Infection or Thigh

Abscess Drainage

• Can be done locally or with anesthesia
• Incise and clean the wound
• Forcepts can widen the track
• Surgeon can break undrained loculi and insert gauze
• If in the hand or breast, dont wait
• Use CT to guide

Chronic Abscess

• Sequestration exists
• Can lead to the formation of fistulas
• Common bacteria is Mycobacterium

Treating Chronic Abscess

• Excise infected areas
• Predisposing factors must be ruled out

Tetanus

• Exotoxin from gram positive bacteria
• Spore, or drumstick
• Bacillus can live in a wound and make the toxin Tetanospasmin
• Affects nerves
• Injury doesnt matter, infection can still occur
• Incubation is 24hrs to 24 days

Symptoms of Tetanus

• Muscle tone and stiffness & reflex spasms
• Cardiac output and tachycardia
• The muscle spasm begins in the neck and face
• Face trismus happens, causing sardonic smile
• Lockjaw can occur
• Painful convulsions occur between 1-3 days from start
• Temperature and pulse increases

Cases of Tetanus

• Normal, convulsions lessen
• Muscle tone returns later
• Fatal cases death occurs from the muscles of the lungs failing
• Vomit

Diagnosing Tetanus

• Mimics Hypo-Calcemic Tetany, which occurs in limbs
• Mimics Strychnine Poisoning, occurring between spasms
• Mimics Meningitis, occurring in the neck
• Can be mistaken as Epilepsy or Hysteria

Prevention from Tetanus

• Take your immunization shots at 2,4,6 months, taking a booster every 7-10 years from there
• Scenarios:
  • If the last dose was within five years, no vaccination is needed
  • Previous dose was more than more than 10 years ago, ensure you get a Booster dose
  • If never immunized, 3 doses of are needed

General Treatment

• With 3000units used to Neutralize the Cytoxin
• Giving this in mild and severe cases with muscle spasms and paralytics
• Severe:
  • Provide artificial ventilation and tracheostomy
  • Isolate them and maintain the room
  • Give prophylaxis and anti-emetics
  • Give penicillin or tetracycline

Tetanus Prognosis

• Vaccinations help prevent death
• Short incubations are even more dangerous
• The elderly and children are weaker
• Facial wounds are often the most dangerous

Gas Gangrene

• Mostly found in war wounds
• Bacteria spreads in the ab wall and cavity
• Caused by Clostridium bacteria
• Found in feces
• Causes tissure damage & pathogens spread
• Amputation may be required due to wounds

Symptoms of Gangrene

• Painful with shock, and vomiting
• Feverish
• Gas is trapped in the tissues
• Skin will swell
• Gas with foul smell
• Rapid spreading

Treatment

• Prophylaxis = Tissue debridement
• Wait a week to suture up wound
• Anti-bacteria agent of penicilin in wounds used to treat
• In the established = excise
• Amputation

Necrotizing

• Fatal infections that spread quickly
• Polymicrobial
• Wounds that need skin grifting
• Ab wall: Fourniers
• Often immunocompromised

Symptoms of Necrotizing

• Severe wound pain
• Untreated = mods
• Examine for Gangrene

Treatment for Necrotizing

• Apply Broad Spectrum
• Remove and excise dead tissue