Infections of the skin and soft tissues

In the structure of surgical diseases, 35-45% fall on surgical infection - post traumatic and postoperative wounds, acute and chronic purulent diseases, development of hospital (nosocomial) infection of the skin and soft tissues.

[1], [2]

Causes of skin and soft tissue infection

Allocate the following reasons:

• surgical infection (aerobic, anaerobic) of soft tissues,
• a trauma of soft tissues, complicated by a purulent infection,
• syndrome of prolonged crushing of soft tissues,
• hospital infection of soft tissues.

Intensive care is indicated in cases of extensive soft tissue infection, which is characteristic of the syndrome of prolonged crushing and the development of anaerobic nonclostridial infection of soft tissues.

Long-term intensive care is associated with a high probability of hospital infection.

Hospital (nosocomial) infection - the development of skin infection after diagnostic and treatment activities. Hospital infection can be associated with laparoscopy, bronchoscopy, prolonged ventilation and tracheostomy, postoperative purulent complications, including in connection with the use of alloplastic materials (endoprosthetics), drainage of the abdominal or thoracic cavity and other causes. Infection of the skin and soft tissues can also be associated with violations of asepsis rules in the performance of therapeutic measures (post-injection abscesses and phlegmon, suppuration of soft tissues during central venous catheterization).

[3], [4], [5]

Infection associated with catheterization of central veins

Infection associated with central venous catheterization is one of the complications (hospital infection) associated with intensive care. Tunnel infection is the development of a soft tissue infection for 2 cm or more from the puncture site and the insertion of a catheter into the central vein.

Clinical symptoms in the field of catheter implantation are hyperemia, infiltration and suppuration or necrosis of soft tissues, tenderness in palpation. Catheter-associated complications are associated with violations of asepsis rules and the formation of an infected biofilm. Biofilm is formed from deposits on the surface of the blood plasma catheter. Most microorganisms, especially S. Aureus and Candida albicans, have a nonspecific mechanism of adhesion, which leads to the formation of a microbial biofilm.

Clinical characteristics of skin and soft tissue infection

[6], [7], [8], [9], [10]

The condition of soft tissues (inflammation, infiltration, viability)

Extensive (more than 200 cm ² ) purulent wounds of soft tissues are one of the frequent variants of the development of surgical infection after extensive injuries and postoperative complications.

Determination of the wound surface area. Measurement formula:

S = (L-4) x K-C,

Where S is the area of the wound, L is the perimeter of the wound (cm) measured by the curvimeter, K is the regression coefficient (for wounds approaching in shape to the square, = 1.013, for wounds with irregular contours = 0.62), C is a constant wounds approaching in shape to the square, = 1.29, for wounds with irregular contours = 1.016). The area of human skin is about 17 thousand cm ².

The defeat of anatomical structures

The involvement of anatomical structures in the process depends on the causes of the infection (trauma, postoperative complications, the syndrome of prolonged crushing, etc.) and the type of pathogenic microflora. Aerobic microflora affects the skin and subcutaneous fat (code on ICD 10 - L 08 8).

The development of anaerobic nonclostridial infection is accompanied by the defeat of deep anatomical structures - subcutaneous tissue, fascia and tendons, muscle tissue. Skin covers in the infectious process are not significantly involved.

The syndrome of prolonged tissue crushing is a common cause of acute ischemia and microcirculatory disturbances, which leads to severe damage to soft tissues, usually anaerobic neklostridialnoyi infection.

Neclostridial phlegmon

Optimal conditions for the development of nonclostridial phlegmon are closed fascial cases with muscles, lack of contact with the external environment, aeration deficiency and oxygenation. As a rule, the skin covers over the affected area are changed little.

The clinical characteristics of infectious soft tissue damage depend on the localization of the infection:

• Cellulite (code for ICD 10 - L08 8) - affection with anaerobic nonclostridial infection of subcutaneous fat.
• Fasciitis (code on ICD 10 - M72 5) - infectious lesion (necrosis) of fascia.
• Myositis (code on ICD 10 - M63 0) - infectious damage to muscle tissue.

Combined lesions of microflora of soft tissues prevail, extending far beyond the primary focus ("creeping" infection). Relatively small changes in the skin do not reflect the extent and extent of infection by the infectious process of soft tissues.

Clinical symptoms - edema of the skin, hyperthermia (38-39 ° C), leukocytosis, anemia, severe intoxication, PON, impaired consciousness.

Composition of microflora (main pathogens)

Species characteristic and frequency of identification of microflora depends on the causes of infection.

• Angiogenic, including catheter-associated infections, about coagulase-negative staphylococci - 38.7%,
  • S. Aureus - 11.5%,
  • Enterocococcus spp-11.3%,
  • Candida albicans - 6.1%, etc.
• Postoperative purulent complications
  • coagulase-negative staphylococci - 11,7%,
  • Enterocococcus spp-17.1%,
  • P. Aeruginosa - 9.6%,
  • S. Aureus - 8.8%,
  • E. Coli - 8.5%,
  • Enterobacter spp - 8,4%, etc.

[11], [12], [13], [14]

Anaerobic nonclostridial soft tissue infection

Neclostridial anaerobes are representatives of the normal human microflora, they are referred to conditionally pathogenic microorganisms. However, under appropriate clinical conditions (severe trauma, tissue ischemia, development of soft tissue infection in the postoperative period, etc.), anaerobic neklo-stridial infection becomes the cause of severe and extensive infectious tissue damage.

The microbial profile includes the association of non-clostridial anaerobes, aerobic and facultative anaerobic microorganisms.

The main causative agents of anaerobic nonclostridial infection. The following clinical types are of greatest clinical importance:

• gram-negative rods - B. Fragilis, Prevotella melaninogemca, Fusobacterium spp,
• Gram-positive cocci - Peptococcus spp., Peptostreptococcus spp.,
• Gram-positive non-spore-forming bacillus - Actinomyces spp., Eubactenum spp., Propionibacterium spp., Arachnia spp., Bifidobacterium spp.,
• Gram-negative cocci - Veillonella spp.

The causative agents of anaerobic neklostridialnoy infection can be Gram-positive cocci - 72% and bacteria of the genus Bacteroides - 53%, less gram positive non-spore-forming bacillus - 19%.

Aerobic microflora in association with anaerobic nonclostridial infection is represented by Gram-negative bacteria of the Enterobactenaceae family of E. Coli - 71%, Proteus spp. - 43%, Enterobacter spp. - 29%.

[15], [16], [17], [18], [19], [20]

Stages of wound infection

• The 1st phase is a purulent wound. The inflammatory reaction of tissues to the damaging factors (hyperemia, edema, pain) prevails, characterized by purulent discharge, associated with the development of the corresponding microflora in the soft tissues of the wound.
• 2nd phase - regeneration phase. The microbial invasion decreases (less than 10 ³ microbes per 1 g of tissue), the number of cells of the young connective tissue increases. In the wound, reparative processes are accelerated.

Postoperative complications

The frequency of postoperative infectious complications depends on the area and conditions of the operative intervention:

• Planned operations on the heart, aorta, arteries and veins (without signs of inflammation), plastic surgery on soft tissues, joint prosthesis (infectious complications) - 5%.
• Operations (aseptic conditions) on the organs of the digestive tract, urinary system, lungs, gynecological operations - 7-10% of infectious complications.
• Operations (inflammatory-infectious conditions) on the organs of the digestive tract, urinary system and gynecological operations - 12-20% of purulent complications.
• Operations in conditions of the current infectious process on the organs of the cardiovascular system, GIT, genitourinary system, musculoskeletal system, soft tissues - more than 20% of complications.

Diagnosis of skin and soft tissue infection

Ultrasound - the determination of the state of soft tissues (infiltration) and the spread of the infectious process (fuzziness).

CT and MRI - the definition of pathologically altered, infected tissues. Cytological and histological examination of wound surface tissues. It allows to determine the phase of wound process and indications to plastic closure of wound surfaces.

Bacteriological study - bacterioscopy, seeding of microflora of wounds. Studies are conducted in dynamics, which allows to determine the type of pathogenic microflora, sensitivity to antibacterial drugs, indications for repeated surgical interventions and plastic operations.

[21], [22], [23]

Treatment of skin and soft tissue infection

Intensive therapy of patients with extensive infectious soft tissue lesions is performed against a background of radical surgical treatment.

Surgical tactics for soft tissue infection consists in the radical excision of all non-viable tissues with the audit of adjacent soft tissues. Soft tissues during anaerobic infection are impregnated with serous cloudy discharge. Surgical intervention leads to the formation of an extensive postoperative wound surface and the need for daily traumatic dressings under anesthesia with a control of the state of soft tissues.

Infection of a large array of soft tissues (several anatomical structures) is accompanied by general manifestations of HSVP, as a result of the entry of biologically active substances into the blood from damaged tissues, and the development of sepsis. Clinical symptoms - swelling of the skin, hyperthermia (38-39 ° C), leukocytosis, anemia, clinical symptoms of severe sepsis (dysfunction or insufficiency of internal organs, severe degree of intoxication, impaired consciousness).

Antibiotic therapy

The clinical diagnosis of anaerobic nonclostridial soft tissue infection involves the association of aerobic and anaerobic microflora and requires the use of broad spectrum agents. Early initiation of empirical antibacterial therapy is advisable to use drugs from the group of carbapenems (imipenem, meropenem 3 g / day) or sulperazone 2-3 g / day.

[24], [25], [26],

Correction of antibacterial therapy

Appointment of drugs for sensitivity - spend 3-5 days on the results of bacteriological culture of microflora. Under the control of repeated bacteriological cultures, it is prescribed (aerobic microflora):

• amoxicillin / clavulanic acid 1.2 g three times a day, intravenously,
•   efalosporiny III-IV generation - cefepime 1-2 g twice daily, intravenously,
• cefoperazone 2 g twice daily, intravenously,
• amikacin 500 mg 2-3 times a day

Taking into account the dynamics of the wound process, it is possible to switch to fluoroquinolones in combination with metronidazole (1.5 g) or clindamycin (900-1200 mg) per day.

Antibacterial therapy is carried out in combination with antifungal drugs (ketoconazole or fluconazole). Sowing mushrooms from sputum, blood - an indication for intravenous infusion of fluconazole or amphotericin B.

Control of adequacy - repeated bacteriological crops, those qualitative and quantitative determination of microflora in infected soft tissues.

Infusion therapy [50-70 ml / (kghsut)] is necessary for correction of water electrolyte losses in case of extensive infection with soft tissue infection, also depends on the area of the wound surface. Assign colloidal, crystalloid, electrolyte solutions.

Adequacy monitoring - indices of peripheral hemodynamics, level of CVP, hourly and daily diuresis.

Correction of anemia, hypoproteinemia and disorders of the blood coagulation system (according to indications) - erythrocyte mass, albumin, fresh-frozen and supernatant plasma.

Control - clinical and biochemical blood tests, coagulogram. Detoxication therapy is carried out using methods of GF, UV, plasmapheresis (according to indications).

Adequacy monitoring - qualitative and quantitative determination of toxic metabolites by gas-liquid chromatography and mass spectrometry, evaluation of neurological status (Glasgow scale).

Immunocorrection (secondary immunodeficiency) - replacement therapy with immunoglobulins.

Control - determination in the dynamics of indicators of cellular and humoral immunity.

[27], [28], [29], [30], [31], [32], [33],

Enteral and parenteral nutrition

Correction of protein-energy losses is an absolutely necessary component of intensive therapy for extensive infections with soft tissue infection. An early start of nutritional support is shown.

The level of protein-energy and water-electrolyte losses depends not only on the catabolic phase of metabolism, hyperthermia, increased nitrogen loss through the kidneys, but also on the duration of the purulent infection and the area of the wound surface.

The extensive wound surface in the 1 st phase of the wound process leads to additional nitrogen losses of 0.3 g, ie about 2 g of protein with 100 cm ².

A prolonged underestimation of protein-energy losses leads to the development of nutritional deficiencies and wound depletion.

Development of nutritional deficiency in patients with surgical infection

Duration of infection, days	Mean nutritional deficiency (15% body weight deficit)	Severe nutritional deficiency (body mass deficit more than 20%)
Less than 30 days (% of patients)	31%	6%
30-60 days (% of patients)	67%	17%
More than 60 days (% of patients)	Thirty%	58%

Monitoring the effectiveness of therapeutic nutrition - the level of nitrogen balance, the concentration of total protein and albumin in the plasma, the dynamics of body weight.

Thus, extensive infections of the skin and soft tissues, especially with the development of anaerobic neklostridialnoy infection or nosocomial (hospital) infection, require a multicomponent and long-term intensive care.

[34], [35], [36], [37],