Postpartum purulent-septic diseases: causes and pathogenesis

Causes of postpartum purulent-septic diseases

At present, there is no doubt that the cause of purulent puerperal diseases are associations of anaerobic-aerobic flora. Each patient is allocated from 2 to 7 pathogens. The causative agents of endometritis after cesarean section are most often the gram-negative bacteria of the Enterobacteriaceae family (Escherichia, Klebsiella, Proteus), with the Escherichia coli prevalent, the frequency of which varies from 17 to 37%.

From gram-positive cocci in the association, enterococci are most often (37-52%) (Gurtova BL, 1995), which is explained by the ability of these microorganisms to produce beta-lactamase. Traditional pathogens - gram-positive staphylo- and streptococci, for example Staphylococcus aureus, are rare - 3-7%. The frequency of allocation of obligate non-spore forming anaerobes from the uterine cavity after endometrial cesarean section, according to some data, reaches 25-40%. The most common are bacteroids and Gram-positive cocci - peptococci, peptostreptococcus, fusobacteria.

A significant role in the development of the process is currently assigned to the opportunistic flora. More often there are diseases caused by gram-negative conditionally pathogenic microorganisms and non-spore forming anaerobes, as well as their associations with other representatives of the opportunistic pathogenic flora.

Controversial and not fully understood the role of transmissible infections. The causative agents of the latter are often identified in the associative flora, together with other pathogens, and it is difficult to judge objectively about their true significance at the present time.

The percentage of detection of genital mycoplasmas in the contents of the uterine cavity is extremely high and reaches 26% for Mycoplasma hominis and 76% for Ureaplasma urealiticum. In most cases, small pathogenic mycoplasmas are released in the endometrium after cesarean section in association with other, much more virulent microorganisms, so it is difficult to say whether they are pathogens or simply parasites.

The incidence of Chlamydia trahomatis is 2-3%, and its role in early postpartum endometritis is being questioned by many authors. At the same time, with late postpartum endometritis, the significance of Chlamydia infection increases dramatically.

Recently, a number of authors have identified in the uterine cavity Gardnerella vaginalis in 25-60% of patients with postpartum endometritis.

According to research data, 68.5% of patients with late (delayed) complications of cesarean section showed associations of aerobic and anaerobic flora, represented by E. Coli, proteus, Pseudomonas aeruginosa, bacteroides.

The frequency of occurrence of pathogens of postoperative purulent-septic complications was as follows: in 67.4% of cases, epidermal and saprophytic staphylococci became causative agents, staphylococcus aureus in 2.17%, non-hemolytic streptococcus in 15.2%, 17.4% E. Coli, 28.3% enterobacteria, 15.2% Klebsiella, 4.3% - Proteus, Trichomonas, Pseudomonas aeruginosa; 26.1% of patients met yeast-like fungi and 19.6% had chlamydia.

Pathogenesis of postpartum purulent-septic diseases

In the overwhelming majority of cases, contamination of the uterus cavity occurs ascending through the process of delivery or in the early postpartum period. During cesarean section, direct bacterial invasion into the circulatory and lymphatic systems of the uterus is also possible. However, the presence of an infectious agent alone is not enough to realize the inflammatory process. It is necessary to have favorable conditions for the growth and reproduction of microorganisms.

Epithelialization and regeneration of the endometrium usually begin on the 5th-7th day of the puerperium and end only after 5-6 weeks after delivery. Being in the uterine cavity immediately after childbirth, lochia, blood clots, the remains of necrotic decidual tissue and the gravidar mucosa create an extremely favorable environment for the reproduction of microorganisms, especially anaerobes. In the cesarean section, the uterus tissues associated with additional traumatization during surgical intervention, in particular, edema, ischemia and destruction of tissues in the seam region, formation of microhematomas, gray, large amounts of foreign sutures, are added to the above-mentioned predisposing factors.

After cesarean section, the entire stratum of the suture on the uterus first becomes infected with the development of not only the endometritis but also the manometritis. Therefore, the inflammatory process in the uterus after abdominal delivery is clearly defined by the author as endomyometritis.

The provoking factors

Essential risk factors for conducting cesarean delivery are:

• emergency operation;
• obesity;
• pre-operative labor;
• prolonged anhydrous period; "Duration of gestation;
• anemia (hemoglobin level less than 12.0 g / 100 ml).

The following are the most significant risk factors for the development of purulent-septic complications in women who underwent a cesarean section.

Genital factors:

• previous history of infertility;
• presence of chronic bilateral salpingo-oophoritis;
• the presence of STI with its activation in the present pregnancy (ureaplasmosis, chlamydia, herpetic infection), bacterial vaginosis;
• Wearing an IUD preceding the present pregnancy.

Extragenital factors:

• anemia;
• diabetes;
• violation of fat metabolism;
• presence of chronic extragenital foci of infection (bronchopulmonary, urogenital systems), especially if they become aggravated in the present pregnancy.

Hospital factors:

• repeated hospitalizations during pregnancy;
• stay in hospital (more than three days) before delivery.

Obstetric factors:

• presence of preeclampsia, especially severe;
• prolonged, prolonged course of labor, anhydrous interval more than 6 hours;
• 3 or more vaginal examinations during labor;
• presence of chorioamnionitis and endomyometritis in childbirth.

Intraoperative factors:

• location of the placenta along the anterior wall, especially placenta previa in the incision;
• operation in conditions of a sharp thinning of the lower segment - with the full opening of the cervix, especially with a prolonged stand of the head in the plane of the entrance to the small pelvis;
• the presence of technical errors during the operation, such as the use of the Gusakov method, not Derfler, inadequate selection of the incision on the uterus (cervical or vaginal cesarean section), which contributes to a sharp disruption of the feeding of the anterior lip of the cervix; use of gross manual methods of removing the head (forcible removal of the head due to rupture of the uterine tissues, pressure on the uterine fundus, vaginal aids), which inevitably leads to the continuation of the incision in the rupture with the transition to the uterine rib, the cervix (with its partial amputation) or the wall of the urinary a bubble; as a rule, it is accompanied by bleeding and the formation of hematomas, which requires additional hemostasis, and the healing of tissues under conditions of hematoma or ischemia (frequent, massive sutures) in such cases sharply increases the chances of failure of the sutures on the uterus;
• unrecognized intraoperative injury of the bladder or ureters when topography changes (repeated operations) or when the head removal technique is violated;
• violation of the technique of sewing the incision (rupture) on the uterus, in particular frequent suturing of the uterus, sewing of tissues ad mass; all this leads to ischemia and necrosis of the lower segment;
• inadequate hemostasis, leading to the formation of hematomas in the vestibule space and (or) the parameter;
• the use of a continuous suture for suturing the uterus, stitching the endometrium (wicking effect), the use of a reactogenic material, especially silk and thick catgut, the use of traumatic cutting needles;
• the duration of the operation is more than 2.5 hours;
• presence of pathological blood loss.

In the development of postpartum complications, in addition to the infection factor and provoking risk factors, the reduction of the protective-adaptive capabilities of the puerperas is of no small importance. In pregnancy, even uncomplicated, as a result of physiological immune depression there is a so-called transient partial immunodeficiency, the compensation of which occurs during delivery through the natural birth canal only to the 5th-6th day of the postpartum period, and after the operation of cesarean section by the 10th day . Complications of pregnancy, extragenital diseases, complicated childbirth, abdominal delivery, pathological blood loss further contribute to a decrease in the immunological reactivity of the woman's body, which can lead to the progression of purulent-septic diseases.

[1], [2], [3], [4], [5], [6], [7], [8], [9]