Sepsis is a common purulent infection that develops due to the penetration and circulation of various pathogens and their toxins in the blood. The clinical picture of sepsis consists of intoxication syndrome (fever, chills, pale earthy coloration of the skin), thrombohemorrhagic syndrome (hemorrhages into the skin, mucous membranes, conjunctiva), metastatic lesions of tissues and organs (abscesses of various localizations, arthritis, osteomyelitis, etc.). Sepsis is confirmed by the isolation of the pathogen from the blood culture and local foci infections. In sepsis, massive detoxification, antibacterial therapy, immunotherapy is indicated; according to indications, surgical removal of the source of infection.
Meaning
Sepsis (blood poisoning) is a secondary infectious disease caused by the ingress of pathogenic flora from the primary local infectious focus into the bloodstream. Today, from 750 to 1.5 million cases of sepsis are diagnosed annually in the world. According to statistics, abdominal, pulmonary and urogenital infections are most often complicated by sepsis, so this problem is most relevant for general surgery, pulmonology, urology, gynecology. Within the framework of pediatrics, problems related to neonatal sepsis are being studied. Despite the use of modern antibacterial and chemotherapeutic drugs, the mortality rate from sepsis remains at a consistently high level – 30-50%.
Sepsis causes
The most important factors leading to the breakdown of anti-infective resistance and the development of sepsis are:
- on the part of the macroorganism – the presence of a septic focus, periodically or permanently associated with the blood or lymphatic channel; impaired reactivity of the body
- on the part of the infectious agent – qualitative and quantitative properties (massiveness, virulence, generalization by blood or lymph)
The leading etiological role in the development of most cases of sepsis belongs to staphylococci, streptococci, enterococci, meningococci, gram-negative flora (Pseudomonas aeruginosa, E. coli, proteus, Klebsiella, Enterobacter), to a lesser extent – fungal pathogens (candida, Aspergillus, actinomycetes).
Detection of polymicrobial associations in the blood increases the mortality rate of sepsis patients by 2.5 times. Pathogens can enter the blood from the environment or be introduced from the foci of primary purulent infection.
The importance of nosocomial infection is great: its growth is facilitated by the widespread use of invasive diagnostic procedures, immunosuppressive drugs (glucocorticoids, cytostatics). In conditions of immunodeficiency, against the background of trauma, operational stress or acute blood loss, infection from chronic foci spreads freely through the body, causing sepsis. The development of sepsis is more susceptible to premature babies, patients who are on ventilator, hemodialysis for a long time; oncological, hematological patients; patients with diabetes mellitus, HIV infection, primary and secondary immunodeficiency.
Pathogenesis
The mechanism of sepsis development is multi-stage and very complex. From the primary infectious focus, pathogens and their toxins penetrate into the blood or lymph, causing the development of bacteremia. This causes activation of the immune system, which reacts with the release of endogenous substances (interleukins, tumor necrosis factor, prostaglandins, platelet activation factor, endothelins, etc.) that cause damage to the vascular wall endothelium. In turn, under the influence of inflammatory mediators, the coagulation cascade is activated, which ultimately leads to the occurrence of DIC syndrome. In addition, under the influence of released toxic oxygen-containing products (nitrogen oxide, hydrogen peroxide, superoxides), perfusion decreases, as well as oxygen utilization by organs. A natural outcome in sepsis is tissue hypoxia and organ failure.
Classification
Forms of sepsis are classified depending on the localization of the primary infectious focus. Based on this feature, primary (cryptogenic, essential, idiopathic) and secondary sepsis are distinguished. With primary sepsis, the entrance gate cannot be detected. The secondary septic process is divided into:
- surgical – develops when an infection is introduced into the blood from a postoperative wound
- obstetric-gynecological – occurs after complicated abortions and childbirth
- urosepsis – characterized by the presence of entrance gates in the departments of the genitourinary apparatus (pyelonephritis, cystitis, prostatitis)
- cutaneous – the source of infection is purulent skin diseases and damaged skin (boils, abscess, burns, infected wounds, etc.)
- peritoneal (including biliary, intestinal) – with localization of primary foci in the abdominal cavity
- pleuro-pulmonary – develops against the background of purulent lung diseases (abscessing pneumonia, pleural empyema, etc.)
- odontogenic – caused by diseases of the dental system (caries, root granulomas, apical periodontitis, periostitis, parotid phlegmon, osteomyelitis of the jaws)
- tonsillogenic – occurs against the background of severe sore throats caused by streptococci or staphylococci
- rhinogenic – develops due to the spread of infection from the nasal cavity and paranasal sinuses, usually with sinusitis
- otogenic – associated with inflammatory diseases of the ear, more often purulent otitis media.
- umbilical – occurs with omphalitis of newborns
According to the time of occurrence, sepsis is divided into early (occurs within 2 weeks of the appearance of the primary septic focus) and late (occurs later than two weeks). According to the rate of development, sepsis can be lightning-fast (with rapid development of septic shock and the onset of death within 1-2 days), acute (lasting 4 weeks), subacute (3-4 months), recurrent (lasting up to 6 months with alternating attenuations and exacerbations) and chronic (lasting more than a year).
Sepsis in its development goes through three phases: toxemia, septicemia and septicopiemia. The toxemia phase is characterized by the development of a systemic inflammatory response due to the onset of the spread of microbial exotoxins from the primary focus of infection; there is no bacteremia in this phase. Septicemia is marked by the dissemination of pathogens, the development of multiple secondary septic foci in the form of microthrombs in the microcirculatory bed; persistent bacteremia is observed. The septicopiemia phase is characterized by the formation of secondary metastatic purulent foci in the organs and bone system.
Sepsis symptoms
The symptoms of sepsis are extremely polymorphic, depending on the etiological form and course of the disease. The main manifestations are caused by general intoxication, multiple organ disorders and localization of metastases.
In most cases, the onset of sepsis is acute, but a quarter of patients have so-called presepsis, characterized by feverish waves alternating with periods of apyrexia. The state of pre-sepsis may not turn into a detailed picture of the disease if the body manages to cope with the infection. In other cases, the fever takes an intermittent form with pronounced chills, alternating with fever and sweating. Sometimes hyperthermia of a permanent type develops.
The condition of the patient with sepsis quickly becomes heavier. The skin becomes a pale gray (sometimes jaundiced) color, the facial features sharpen. Herpetic rashes on the lips, pustules or hemorrhagic rashes on the skin, hemorrhages in the conjunctiva and mucous membranes may occur. In the acute course of sepsis, bedsores quickly occur in patients, dehydration and exhaustion increase.
In conditions of intoxication and tissue hypoxia, multiple organ changes of varying severity develop in sepsis. Against the background of fever, signs of central nervous system dysfunction are clearly expressed, characterized by lethargy or excitement, drowsiness or insomnia, headache, infectious psychoses and coma. Cardiovascular disorders are represented by arterial hypotension, weakening of the pulse, tachycardia, deafness of heart tones. At this stage, sepsis can be complicated by toxic myocarditis, cardiomyopathy, acute cardiovascular insufficiency.
The respiratory system reacts to pathological processes occurring in the body with the development of tachypnea, lung infarction, respiratory distress syndrome, respiratory failure. On the part of the gastrointestinal tract, anorexia is noted, the occurrence of “septic diarrhea” alternating with constipation, hepatomegaly, toxic hepatitis. Violation of the function of the urinary system in sepsis is expressed in the development of oliguria, azotemia, toxic nephritis, ARF.
In the primary focus of infection with sepsis, characteristic changes also occur. Wound healing slows down; granulations become sluggish, pale, bleeding. The bottom of the wound is covered with a dirty grayish coating and areas of necrosis. What is separated acquires a cloudy color and a fetid smell.
Metastatic foci in sepsis can be detected in various organs and tissues, which causes the layering of additional symptoms characteristic of the purulent-septic process of this localization. The consequence of the introduction of infection into the lungs is the development of pneumonia, purulent pleurisy, abscesses and gangrene of the lung. With metastases to the kidneys, pyelitis, paranephritis occur. The appearance of secondary purulent foci in the musculoskeletal system is accompanied by the phenomena of osteomyelitis and arthritis. With brain damage, the occurrence of brain abscess and purulent meningitis is noted. There may be metastases of purulent infection in the heart (pericarditis, endocarditis), muscles or subcutaneous fat (soft tissue abscesses), abdominal organs (liver abscess, etc.).
Complications
The main complications of sepsis are associated with multiple organ failure (renal, adrenal, respiratory, cardiovascular) and DIC syndrome (bleeding, thromboembolism).
The most severe specific form of sepsis is septic (infectious-toxic, endotoxic) shock. It develops more often with sepsis caused by Staphylococcus and gram-negative flora. The precursors of septic shock are disorientation of the patient, visible shortness of breath and impaired consciousness. Circulatory disorders and tissue metabolism are rapidly increasing. Acrocyanosis on the background of pale skin, tachypnea, hyperthermia, a critical drop in blood pressure, oliguria, increased pulse rate up to 120-160 beats are characteristic. per minute, arrhythmia. Mortality in the development of septic shock reaches 90%.
Diagnostics
Recognition of sepsis is based on clinical criteria (infectious and toxic symptoms, the presence of a known primary focus and secondary purulent metastases), as well as laboratory parameters (blood culture for sterility).
At the same time, it should be borne in mind that short-term bacteremia is also possible with other infectious diseases, and blood cultures with sepsis (especially against the background of antibiotic therapy) are negative in 20-30% of cases. Therefore, blood culture for aerobic and anaerobic bacteria should be carried out at least three times and preferably at the height of a febrile attack. Also, the contents of the purulent focus are backfilled. PCR is used as an express method of isolating the DNA of the causative agent of sepsis. In peripheral blood, there is an increase in hypochromic anemia, acceleration of ESR, leukocytosis with a shift to the left.
It is necessary to differentiate sepsis from lymphogranulomatosis, leukemia, typhoid fever, paratyphoid A and B, brucellosis, tuberculosis, malaria and other diseases accompanied by prolonged fever.
Sepsis treatment
Patients with sepsis are hospitalized in the intensive care unit. The complex of therapeutic measures includes antibacterial, detoxification, symptomatic therapy, immunotherapy, elimination of protein and water-electrolyte disorders, restoration of organ functions.
In order to eliminate the source of infection that supports the course of sepsis, surgical treatment is performed. It may consist in opening and draining a purulent focus, performing necrectomy, opening purulent pockets and intraosseous ulcers, sanitizing cavities (with soft tissue abscess, phlegmon, osteomyelitis, peritonitis, etc.). In some cases, resection or removal of the organ together with the abscess may be required (for example, with an abscess of the lung or spleen, kidney carbuncle, pyosalpinx, purulent endometritis, etc.).
The fight against microbial flora involves the appointment of an intensive course of antibiotic therapy, flow washing of drains, local administration of antiseptics and antibiotics. Before receiving a culture with antibiotic sensitivity, therapy is started empirically; after verification of the pathogen, if necessary, an antimicrobial drug is changed. In sepsis, cephalosporins, fluoroquinolones, carbapenems, and various combinations of drugs are usually used for empirical therapy. In candidosepsis, etiotropic treatment is carried out with amphotericin B, fluconazole, caspofungin. Antibiotic therapy continues for 1-2 weeks after normalization of temperature and two negative blood cultures.
Detoxification therapy for sepsis is carried out according to general principles using saline and polyionic solutions, forced diuresis. In order to correct CBS, electrolyte infusion solutions are used; amino acid mixtures, albumin, and donor plasma are introduced to restore protein balance. To combat bacteremia in sepsis, extracorporeal detoxification procedures are widely used: plasmapheresis, hemosorption, hemofiltration. With the development of renal insufficiency, hemodialysis is used.
Immunotherapy involves the use of antistaphylococcal plasma and gamma globulin, transfusion of leukocyte mass, the appointment of immunostimulants. Cardiovascular drugs, analgesics, anticoagulants, etc. are used as symptomatic agents. Intensive drug therapy for sepsis is carried out until a steady improvement in the patient’s condition and normalization of homeostasis indicators.
Prognosis and prevention
The outcome of sepsis is determined by the virulence of the microflora, the general condition of the body, the timeliness and adequacy of the therapy. Elderly patients with concomitant common diseases and immunodeficiency are predisposed to the development of complications and an unfavorable prognosis. With various types of sepsis, the mortality rate is 15-50%. With the development of septic shock, the probability of death is extremely high.
Preventive measures against sepsis consist in the elimination of foci of purulent infection; proper management of burns, wounds, local infectious and inflammatory processes; compliance with asepsis and antiseptics when performing therapeutic and diagnostic manipulations and operations; prevention of hospital infection; vaccination (against pneumococcal, meningococcal infection, etc.).
Literature
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- National variation in United States sepsis mortality: a descriptive study / Henry E. Wang, Randolph S. Devereaux, Donald M. Yealy, Monika M. Safford, George Howard // Int J Health Geogr. 2010; 9: 9.link
- Astiz M. E., Rackow E. C. Septic shock // Lancet . — 1998; 351 (9114): 1501-1505.link
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