amniotic infection syndrome
Introduction
Introduction to amniotic infection syndrome Intraamniotic infectious syndrome (IAIS) is a general term for infection caused by pathogenic microorganisms entering the amniotic cavity during pregnancy and childbirth, including amniotic fluid, fetal membranes (chorion, amnion and decidua), placenta and even uterine infection. basic knowledge Sickness ratio: 0.05% Susceptible population: pregnant women Mode of infection: non-infectious Complications: shock, diffuse intravascular coagulation
Cause
Causes of amniotic infection syndrome
(1) Causes of the disease
1. Membrane rupture The traditional obstetric rupture of fetal membrane is the cause of IAIS. The longer the rupture of the membrane is, the higher the incidence of IAIS is. The rupture or premature rupture of the membrane is only the cause of IAIS. The modern obstetrics found that the membrane rupture and IAIS Mutual causality, and IAIS may be the main cause of rupture of membranes. The presence of IAIS due to various reasons leads to membrane destruction, cervical dilatation and uterine contraction, and membrane rupture. The amniotic cavity is the same as the vagina. Prolonging the infection is complicated and serious.
2. The iatrogenic infection caused by obstetrician operation includes amniocentesis for various purposes of diagnosis and treatment, fetal surgery or intrauterine surgery, amniocentesis and fetal mirror technique, perinatal vaginal examination, anal examination and vagina Surgical operation, etc.
3. Pregnancy reproductive system infection mainly refers to cervical and vaginal inflammation, such as common bacterial vaginosis, fungal vaginitis and trichomonas vaginitis, etc., cervical or intravaginal bacteria, up through the ruptured or unruptured amniotic membrane, reaching The amniotic cavity is further propagated in the amniotic cavity, causing serious infection.
4. Chorioamnionitis usually occurs in pregnant women with subclinical chronic endometritis before pregnancy. Inflammation during pregnancy involves the placenta and membrane, and further spreads into the amnion and amniotic cavity.
(two) pathogenesis
IAIS is characterized by bacterial inflammation or inflammation caused by pathogenic microorganisms, and its pathogenic mechanism and effects on mother and child are derived from the inflammatory process caused by bacteria and bacteria.
1. Bacterial and bacterial products The bacteria themselves continue to grow, divide and spread, and bacteria rupture due to various reasons. The bacteria itself and various bacterial lysates and metabolites such as endotoxin or exotoxin can directly or indirectly affect pregnant women and fetuses. Caused various damages.
2. Inflammatory response
(1) High fever or fever: Fever is an important feature of various inflammations. In addition to the various effects of IAIS fever on pregnant women, don't forget the effects of fever on the fetus. Fever or even high fever can cause serious fetal water and electrolyte disturbances or serious Central nervous system damage.
(2) Vascular response: Inflammation is defined as the response of blood vessels in living tissues to various stimuli. The vascular response is the center of various inflammations, including the various reactions of the blood vessel wall itself and blood components in the blood vessels, and the blood vessels in the placenta. The response is crucial for the effects of pregnancy, directly related to placental function. The vascular reactions in the placenta are mainly congestion, edema, exudation, hemorrhage, thrombosis, thrombosis and various denaturation and necrotic tissue, calcification, necrosis, Fibrosis, etc., these changes can reduce the material exchange function of the placenta, causing fetal distress.
(3) Abnormal immune function: bacterial inflammation can stimulate the body's immune system, including non-specific cellular and humoral immunity, specific cellular and humoral immune functions, and moderate increase in immune function is mainly to improve the body's resistance, but the immune mechanism Mediation is also an important mechanism for causing various inflammatory lesions, especially placental damage. Proteasomes such as MMP8 and MMP9 released by inflammatory cells such as leukocytes can destroy the normal tissue structure of the membrane, prone to premature rupture of membranes, and immune system. Changes in cells and cytokines are currently important methods for detecting subclinical IAIS, including IL-6, IL-8, GCSF and TNF-.
(4) Inflammatory mediators: There are kinin bradykinin systems, coagulation and anticoagulant systems, and arachidonic acid systems involved in the inflammatory process. Prostaglandins produced by the arachidonic acid system are of great significance to obstetrics. Years of research have found that PGE2 and PGF2 can cause strong contractions, dilated cervical cervix, and difficult to control contractions.
(5) Bacteria, bacterial metabolism or lysate during bacterial inflammation, cells, factors and mediators of inflammatory reactions may enter the fetus through the respiratory system, digestive system, skin and umbilical cord of the fetus, causing various reactions.
Prevention
Amniocentesis infection prevention
1. Mainly for the prevention of high risk factors for amniocentesis. First of all, the treatment of premature rupture of membranes. At present, it is recommended to use antibiotics for 12 hours after the membrane is broken. It is also advocated that preventive use will occur once there is premature rupture of membranes. Antibiotic treatment, when the premature rupture of membranes is estimated to be fetal maturity (most of the gestational age reaches 34 weeks, the fetal lung is mature), it is advisable to terminate the pregnancy early, about 70% of pregnant women after 6 days of premature rupture of membranes naturally start delivery within 24 hours, if There is still no contraction at 24h. Intravenous infusion of oxytocin should be used for induction of labor. It is also suggested that after 12 hours of rupture of the membrane, it is still not in labor. The vaginal fornix is treated with misoprostol, which can cause the delivery to advance without increasing the cesarean section rate. The use of oxytocin and the occurrence of amniocentesis, if the gestational age is <34 weeks at the time of membrane rupture, in order to ensure the survival of the fetus outside the uterus, it is advisable to use expectant therapy, expecting the treatment period, promoting fetal lung maturation and preventing infection simultaneously. Regarding whether the use of corticosteroids to promote fetal lung maturation increases the chance of intrauterine infection, it is still unclear, but in any case, fetal lung immature can cause neonatal hyaline membrane disease to be more harmful than possible intrauterine infection. Heavy, therefore, it is still advocated that when rupturing the membrane for 28 to 34 weeks of pregnancy, dexamethasone or betamethasone is used to promote fetal lung maturation. As for the premature rupture of membranes during the gestational weeks <28 weeks, many advocate positive induction of labor, so as not to expect time. If the intrauterine infection is too long, it is worth noting that the expectation is too long. Although prophylactic use of antibiotics can reduce intrauterine infection, it has little effect on improving the prognosis of perinatal children.
2. Treatment of asymptomatic bacteriuria Asymptomatic bacteriuria is a common urinary tract infection during pregnancy, 3% to 10% of pregnant women have had asymptomatic bacteriuria, the incidence of which is related to race, maternal birth and social status 30% to 50% of patients with asymptomatic bacteriuria develop pyelonephritis. A recent summary analysis shows that patients with asymptomatic bacteriuria during pregnancy have a higher risk of preterm birth and low birth weight, and are also found to be asymptomatic. Bacterial urinary tract is closely related to intrauterine infection. Therefore, active treatment of asymptomatic bacteriuria can reduce the incidence of intrauterine infection.
3. Actively deal with delayed production, pay attention to the disinfection and cleaning work of various operations during the labor process, enhance the sterile awareness of the labor process to avoid excessive anal examination and vaginal examination, usually not more than 10 times in the labor process.
4. Treatment of systemic infectious diseases in pregnant women It has been reported that in pregnant women with pneumococcal lobar pneumonia, although there is no inflammatory pathological change in the lungs after neonatal death, the lung tissue is cultured with S. pneumoniae, usually, various pathogens. The blood can be spread by blood, transmitted to the uterus, causing intrauterine infection. Pregnant women suffering from infectious diseases, including various specific and non-specific infections, can reduce the chance of intrauterine infection after active treatment, and actively treat Urinary tract infection during pregnancy to reduce the occurrence of complications.
5. Prevention of intrauterine infection TORCH, do a good job in health education, when necessary, the corresponding vaccination for women of childbearing age.
6. In the treatment of bacterial vaginosis bacterial vaginosis, the nature of vaginal secretions changes, the number of lactobacilli in the vagina decreases, and the bacteria associated with bacterial vaginosis increase, Gram-negative bacteria and anaerobic bacteria such as Gardnerella The incidence of bacterial vaginosis during pregnancy is estimated to be around 16%, which is a common cause of abnormal vaginal discharge in pregnant women, but nearly half of patients with bacterial vaginosis are asymptomatic. There are many studies suggesting that bacterial vaginosis is closely related to intrauterine infection. Some people even think that bacterial infection of the lower genital tract is a sign of upper genital tract infection, and the pathogen causing bacterial vaginosis can pass through the mucus plug of the cervical canal. Through the intact membrane, amniotic cavity infection, bacterial endotoxin and proteolytic enzymes, mucin, sialidase, IgA protein lyase and phospholipase increased in the vagina of patients with bacterial vaginosis, and the increase of these cytokines It is closely related to the occurrence of intrauterine infection. Some people have found a history of bacterial vaginosis, and the fluff occurs during cesarean section. Amnionitis and postpartum uterine incidence of meningitis, compared with patients without a history of bacterial vaginosis to 4 times higher, therefore, aggressive treatment of bacterial vaginosis in pregnancy to reduce the incidence of intrauterine infection is important.
Complication
Complications of amniotic infection syndrome Complications, diffuse intravascular coagulation
If the amount of pathogen is large, a large amount of endotoxin or virulence is generated, and inflammation spreads to the myometrium or is accompanied by systemic infection, symptoms of systemic poisoning may occur, even shock or DIC. In severe cases, maternal and child death may occur.
Symptom
Symptoms of amniotic infection syndrome Common symptoms Amniotic cavity infection Uterine tenderness Itching abdominal pain High fever Premature rupture of fetal membranes Cold heart rate Changes of relaxation Thermal tachycardia
Subclinical amniocentesis syndrome can be clinically free of any symptoms. Only clinical amniocentesis syndrome has clinical symptoms, but the symptoms often lack specificity, so it is often not valued by clinicians, resulting from different pathogens. Amniocentesis infections have different clinical manifestations, but most cases have the following symptoms.
1. Premature rupture of membranes. All patients are accompanied by premature rupture of membranes. With the prolongation of rupture time, the possibility of infection in amniotic cavity is greater. Some authors believe that premature rupture of membranes exceeds 24 hours, then amniotic membrane The incidence of cavity infections exceeds 30%.
2. With the further expansion of the scope of inflammation, the body temperature of pregnant women increases, the body temperature exceeds 37.5 °C when the premature rupture of membranes exceeds 37.5 °C, and the cause of amniocentesis infection should be considered. The temperature of pregnant women is increased with the increase of heart rate. However, it is necessary to pay attention to the physiological rate of pregnant women during pregnancy. The heart rate of pregnant women can be slightly faster. However, when the heart rate is >100 beats/min and other causes cannot be found, the possibility of amniocentesis infection should be considered. Some pregnant women may have chest tightness and discomfort.
3. Pregnant women with elevated white blood cells, but pay attention to the physiological changes in blood during pregnancy can show an increase in bleeding white blood cell count. In addition, white blood cell counts vary widely, but generally within 20 × 109 / L, therefore, dynamic blood can be used Changes in white blood cell count, if the white blood cell count is progressively elevated or accompanied by nuclear left shift phenomenon, it indicates amniotic cavity infection, if only the left side of the nuclear phenomenon usually indicates serious infection.
4. In addition to inflammation and villus and decidua, it can further invade the myometrium. It can cause uterine tenderness, inflammation invades the placenta and membrane, pathogens produce endotoxin, can cause interstitial edema, and fetal hypoxic injury. , the performance of fetal heart rate is accelerated, up to 160 ~ 180 times / min, if the fetal heart rate exceeds 180 times / min, often prompted a serious intrauterine infection.
5. Before and after the emergence of the sheep cavity infection syndrome, vaginal purulent secretion may occur. As the condition worsens, the amniotic fluid gradually changes from clarification to turbidity, and the vaginal secretions become purulent and stench. taste.
Examine
Amniocentesis infection test
Maternal blood determination
(1) ESR: It is a non-specific method for detecting the presence or absence of infection. Any infection is accompanied by an increase in erythrocyte sedimentation rate, including autoimmune diseases such as SLE (systemic lupus erythematosus), and erythrocyte sedimentation rate during normal pregnancy. Will accelerate, if >60mm / h, the sensitivity of diagnosis of amniotic infection syndrome is 65%, the specificity is 100%, because the erythrocyte sedimentation test as a diagnostic of amniotic infection syndrome is less sensitive, it limits its clinical application .
(2) White blood cell count: Leukocyte elevation is the gold standard of infection, but it also lacks specificity. As a diagnosis of amniotic infection syndrome, the positive predictive value or negative predictive value are 40%-75% and 52%-89%, respectively. As for how much white blood cells should be elevated to diagnose amniocentesis, it is not certain that white blood cells have a high specificity for the diagnosis of obvious infections, but for histological velvet or amniotic fluid culture and mild clinical infections. , its sensitivity and positive predictive value are lower.
(3) maternal blood C-reactive protein (CRP): CRP is a reaction result of the body after infection. It is produced by the liver and is also non-specific. It is produced by IL-6. At present, there are many research evaluations. The value of CRP in the diagnosis of asymptomatic intrauterine infection, but the positive predictive value and negative predictive value vary greatly among the researchers (40% to 90%), the false increase in the case of contractions more than 6h or other Infectious diseases exist, but if there is a significant increase, or increase after the beginning of the lower, there is a certain diagnostic value, if the increase is more than 30%, it has a greater predictive value for intrauterine infection, Studies have shown that if CRP is elevated 12 h before delivery, the positive predictive value of intrauterine infection is predicted to be 100%. In addition to the intrauterine infection, CRP elevation has a certain correlation with neonatal infection. In short, In general, CRP is less sensitive and limits its clinical application.
(4) Detection of cytokines: the value of IL-6 in maternal blood in the diagnosis of amniotic infection syndrome. Many scholars have tried to detect cytokines from maternal blood to diagnose amniocentesis, and Lewis has detected 57 cases. 24 to 35 weeks of premature rupture of pregnant women with premature delivery of IL-6 levels in the blood, 35 cases of IL-6 increased, 27 cases of neonatal at least 1 complication (including neonatal hyaline membrane disease, neonatal necrosis Inflammitis, intraventricular hemorrhage, neonatal sepsis and congenital pneumonia), of which 24 patients had higher levels of IL-6 in the blood, and only 11 of the 30 patients without neonatal complications had higher IL-6 than normal (OR= 13.8, 95% CI, 2.9374.7), among the 13 pregnant women with neonatal complications who used corticosteroids before delivery, 10 of them had higher levels of IL-6 in the blood, and 32 pregnant women with amniocentesis syndrome. Among them, 24 cases (75%) had higher IL-6 than normal, and only 11 cases (44%) of the 25 cases without amniocentesis were higher than normal (P0.03, OR 3.82, 95%, CI 1.09~13.0), Murtha found that when IL-6>8ng/L (8pg/ml), amniocentesis can be diagnosed [positive predictive value (PPV) = 96%, negative predictive value (NPV) = 95%], IL -6 as a kind Cytokines have high specificity in diagnosing infectious diseases and are released in the early stage of inflammation. In addition, because of the convenience of taking samples, clinical use is convenient, but for its value as a diagnostic for amniocentesis syndrome, Prospective studies are still required for further evaluation.
2. Amniocentesis amniocentesis is used as a diagnostic method for amniotic cavity infection syndrome. At present, the diagnostic gold standard for amniotic cavity infection syndrome is still amniocentesis, but the shortcoming is that the results are slow, premature fetal membranes are early. When broken, nearly 80% of amniotic fluid culture positive patients will develop into obvious clinical infections, while only 10% of culture negative patients develop obvious clinical infections. Therefore, when diagnosing neonatal infection and clinical chorioamnionitis, PPV was 67%, and NPV was 95%. Amniotic fluid culture could not identify the site of infection. In addition, this method has limited diagnostic value for mycoplasma and chlamydia infection.
(1) Amniotic Gram staining examination: amniotic fluid smear Gram staining is an old and widely used method because it is simple and convenient to operate, especially suitable for those with broken membranes, white blood cells and bacteria in the smear. Both suggest the presence of amniocentesis syndrome. The sensitivity of this test is 23% to 60%, the specificity is 76% to 100%, and the negative predictive value can reach 63% to 100%. The value of the test is that if the test is negative, the presence of intrauterine infection can be basically ruled out, but for those who have not broken the membrane, amniocentesis is required, thus limiting its clinical application.
(2) Determination of glucose concentration in amniotic fluid: There are many studies that the low glucose concentration in amniotic fluid is one of the manifestations of amniotic cavity infection syndrome. Gauthier detected the concentration of amniotic fluid glucose in 91 pregnant women and found that the concentration of amniotic fluid glucose was <0.94 mmol. At /L (17mg/dl), 80% had amniotic infection syndrome, with a sensitivity of 73%, a specificity of 90%, a positive predictive value of 87%, and a negative predictive value of 75%, but there are reports that This method has limited value in diagnosing intrauterine infections.
(3) Other examinations: The white blood cell count of amniotic fluid smear is at or above 20×106/L (20/mm3) as the diagnostic criteria, and the sensitivity for diagnosing intrauterine infection is 80%, the specificity is 90%, positive prediction The value and negative predictive value were 96% and 85%, respectively. PCR method was used to detect bacterial 16s rDNA in amniotic fluid, and the sensitivity was 100%. However, this method requires special equipment and time-consuming detection, and detection of catalase in amniotic fluid as intrauterine infection. The diagnostic method and its positive predictive value and negative predictive value are 95% and 88%, respectively. This method is expected to be a better method for diagnosing amniocentesis.
(4) Cytokines: The current diagnosis of intrauterine infection is focused on the use of inflammatory cytokines, which are small molecule glycoproteins produced by different types of cells, especially those involved in immune responses. Intrauterine infection can produce these inflammatory factors in the placenta. The two types of cytokines (IL-1, IL-6) in amniotic fluid are significantly increased during intrauterine infection. The value of diagnosis of amniocentesis is better than amniotic fluid staining. The concentration of glucose in amniotic fluid was higher. The amniotic fluid IL-6 exceeded 7.9g/L (7.9ng/ml) as the standard for the diagnosis of amniotic fluid culture. The positive predictive value and negative predictive value were 67% and 86%, respectively. There is a significant increase in IL-6 in premature rupture of membranes with premature rupture of membranes. However, there is no clear standard value to distinguish the presence or absence of intrauterine infection. The value of IL-1 in cord blood of infected patients and the length of incubation period are not There is a clear correlation between the relationship between IL-1 and perinatal prognosis.
Amniocentesis should be adopted for the above examination methods, and the success rate of amniocentesis is 45% to 97%, and there are certain complications. It is not recommended to use the above method to diagnose amniocentesis syndrome in all cases, but for In cases of premature rupture of membranes, the above methods have great advantages.
Some people have detected the relationship between IL-8 and intrauterine infection in urine. It is found that the positive predictive value and negative predictive value of IL-8 in urine as a diagnosis of amniotic infection syndrome are 71% and 82%, respectively. This method is simple and practical. However, its value is currently subject to further evaluation.
(5) enzyme: due to premature rupture of membranes or amniotic cavity infection syndrome, the amnion extracellular matrix has a common performance, that is, the degradation of extracellular matrix, matrix metalloproteinases (MMPs) are in the process Key enzymes, the activity of the enzyme is enhanced in this pathological process, and tissue inhibitors of matrix emtalloproteinases (TIMPs) can be covalently bound to MMPs to reduce their activity, and MMPs degrading human amniotic membrane are MMP- 2, the corresponding inhibitor is TIMP-2, Maymon study found that premature rupture of membranes or amniotic cavity infection syndrome, there is no significant correlation between MMP-2 concentration in amniotic fluid and gestational age; in premature rupture of membranes or There was no significant difference in MMP-2 in amniotic fluid between the intact membranes. On the contrary, the pregnant women who gave birth naturally had a lower TIMP-2 concentration in the amniotic fluid than the pregnant women who had not yet had labor. There was amniotic infection syndrome. Premature rupture of membranes, whether it is premature or full-term, the concentration of TIMP-2 in amniotic fluid is also significantly lower, therefore, TIMP-2 in amniotic fluid can be used as a diagnostic index of amniocentesis.
3. Fetal biophysical behavior test diagnosis After intrauterine infection of amniotic cavity infection syndrome, the prostaglandin (PG) in amniotic fluid is elevated, the latter can change the biological behavior of the fetus, and the intrauterine infection can make the interstitial edema and umbilicus Vasoconstriction, thus increasing the vascular resistance of the placenta, so that fetal oxygen supply is affected, and then the fetal heart rate and fetal movement changes, through fetal heart rate test and B-ultrasound examination, you can determine whether the fetus has intrauterine infection.
(1) Determination of amniotic fluid: There is a correlation between amniotic fluid volume and amniotic cavity infection syndrome when there is premature rupture of fetal membranes. Vintzileos divides premature rupture of membranes into three groups according to the size of amniotic fluid level, and finds that oligohydramnios is too small. The highest incidence of amniotic fluid <1cm) is the highest incidence of clinical amnion and neonatal sepsis. The predicted positive and negative predictive value of maternal and child infection are 67% and 87%, respectively. The premature rupture of membranes is too low. A better indicator for predicting poor prognosis in perinatal children.
(2) NST examination: using non-reactive NST as an indicator for predicting amniocentesis syndrome, the sensitivity of amniotic fluid culture positive is 86%, the specificity is 70%, and the positive predictive value and negative predictive value are 75%, respectively. And 82%, while predicting clinical and subclinical chorioamnionitis sensitivity and specificity were 78% and 86%, respectively, while the positive predictive value and negative predictive value were 68% and 92%, respectively, there are reports that no Reactive NST can not predict the occurrence of intrauterine infection and neonatal sepsis, but in general, most of the results suggest that there is a significant correlation between non-reactive NST and fetal heart rate and intrauterine infection, and this experiment is also considered It is best to carry out within 24 hours before delivery, when the predicted value is the largest. If the delivery is more than 24h, the predicted value will be significantly reduced. There is no evidence that the premature rupture of membranes is premature after treatment according to the results of NST. What is the relationship between pregnancy prognosis?
(3) Fetal biophysical score (BPP): a method for real-time observation of intrauterine activity using ultrasound, including amniotic fluid volume (AF), fetal respiratory-like movement (FBM), fetal movement (FM), and muscle tone (FT) And five factors of fetal heart rate (FHR) reactivity, BPP was initially used to assess the intrauterine health status of prenatal fetuses with high-risk pregnancies. In 1985, Vintzileos first used BPP scores to diagnose intrauterine infections. Many studies have conducted in-depth research on the value of BPP in the diagnosis of intrauterine infection. Gauthier performed BPP examination on 111 cases of premature rupture of membranes. It was found that BPP score was closely related to intrauterine infection. Flemming found that within 24 hours before delivery, Low BPP score is closely related to histological chorioamnionitis. Vintzileos found BPP score <8 points. It is more sensitive to predicting maternal infection than amniotic fluid culture and Gram staining smear. According to BPP<8, it is actively treated. Compared with chorioamnionitis, the prognosis of pregnancy is better, but it can not reduce the neonatal mortality rate. In the five indicators of fetal biophysical score, each score has only 2 cases, 0 or 2 points. Fetus in There are not only the number of activities in the palace, but also the quality of the body, because the meaning of body movement and limb movement may not be the same. Therefore, Robert put forward the concept of fetal activity ability, and the time of fetal activity in the 30min observation period. As an indicator of fetal activity, fetal activity as a predictor of intrauterine infection is more sensitive and specific than BPP, with sensitivity of 96% and 92%, respectively, and specificity of 82% and 59%, respectively. Conversely, Goldstein found that the activity of the fetus with amniotic cavity infection decreased, intrauterine infection caused a progressive decrease in fetal oxygen supply, which led to a decrease in BPP score. Usually, the first affected biophysical index was NST, which appeared unresponsive. The decrease of FBM and the lower the BPP score, the greater the possibility of intrauterine infection. When the BPP score is 10, 8, 6, 4 and 2 points, the positive rate of amniotic fluid culture is 27%, 48%, 73%, 85 respectively. % and 100%, with the appearance of FM and FT abnormalities, BPP predicts positive and negative predictive value of intrauterine infection, but the predicted value of BPP is more than 24h, but this predictive value decreases, but intrauterine infection Despite the decline in BPP, fetal acidemia is not obvious, suggesting that the cause of intrauterine infection affecting fetal activity remains unclear and may be related to the release of prostaglandins and other cytokines, therefore, how intrauterine infection affects fetal activity The pathophysiological mechanism of capacity still needs further study. It is found that FBM predicts the highest value of intrauterine infection in BPP 5 indicators. Goldstein found that FBM is normal, and its negative predictive value for predicting intrauterine infection is 100%. Roussis found that FBM disappeared. The positive and negative predictive values were 56% and 99%, respectively, which is equivalent to the predicted value of BPP 4 points. Of course, there are also many studies that BPP can not predict the presence or absence of infection in the uterus.
Doppler examination, some people think that the umbilical blood flow S / D ratio increased, suggesting the presence of intrauterine infection, Flemming for the premature rupture of membranes, umbilical blood flow S / D ratio test and BPP examination, found fluff Membrane amniocentesis has an abnormal S/D ratio. If the S/D ratio is increased by 15%, the positive and negative predictive values of histological chorioamnionitis are 71% and 61%, respectively. Yucal compares S/D. The relationship between the ratio and the pathological examination of the placenta found that in patients with histological chorioamnionitis, the ratio of S/D ratio was increased by one-fold compared with that of women without chorioamnionitis, but some authors reported S/D ratios. Abnormalities have little to do with chorioamnionitis. Therefore, the value of umbilical blood flow S/D ratio in the diagnosis of intrauterine infection needs further study.
Diagnosis
Diagnosis and diagnosis of amniotic infection syndrome
According to the clinical manifestations of the medical history, laboratory tests can be diagnosed. The clinical manifestations are divided into clinical and subclinical types. The total incidence of IAIS is 5% to 10%, and the clinical type is about 12.5%. The rest are subclinical.
Clinical IAIS
(1) Medical history:
Previous premature birth, history of puerperal infection, history of premature rupture of membranes, history of previous vaginitis and cervicitis.
(2) Symptoms:
Symptoms of systemic poisoning caused by infectious fever, abdominal pain caused by inflammation of the reproductive system, abnormal vaginal secretions and genital itching, uterine contractions caused by inflammatory stimuli and even labor.
(3) Signs:
The signs of IAIS are many and complex, and there are direct relationships with clinical diagnosis, including the following.
1 fever: body temperature exceeds 37.8 ° C, can reach above 39 ° C, is a retention or relaxation heat, can be accompanied by chills;
2 pregnant women with tachycardia: pregnant women heart rate more than 100 times / min;
3 Abdominal examination: due to inflammatory irritation, peritoneal irritation in the uterus, manifested as increased tension, tenderness, rebound tenderness, the pain is persistent, there is no contraction, and the intensity increases during contractions;
4 obstetric examination: regular or irregular contractions, shortening of the cervical canal or dilatation of the cervix; may occur with water; vaginal odor secretion, which may be a purulent discharge of local inflammation of the cervix or vagina, or Purulent amniotic fluid; if the rupture time is longer, the amniotic fluid is less, and the infection is serious, the purulent amniotic fluid at this time is easily overlooked, which is mistaken for purulent cervix or vaginal discharge, especially when the patient's medical history is unclear;
5 fetal arrhythmia: usually manifested as fetal tachycardia, FHR baseline more than 160 beats / min, can last more than 190 times / min, this tachycardia is a positive response or generation of fetal fever and placental inflammation Reimbursement, but the time is too long or the inflammatory condition is serious, decompensation, fetal heart rate slows, bradycardia, usually poor prognosis.
(4) Blood routine: The blood system of IAIS patients is the same as acute infectious inflammation, which is characterized by an increase in the number of white blood cells, an increase in the proportion of neutrophils, and a shift in the left nucleus, but the white blood cells of normal pregnant women show an increase in white blood cells. More than 15 × 109 / L is meaningful for the diagnosis of IAIS.
(5) Microbiological examination:
1 Gram staining of amniotic fluid: Gram staining of amniotic fluid is a quick and simple method for clear pathogenic bacteria, but this method has high false negative rate and can not find the defects of chlamydia and mycoplasma;
2 Bacterial culture: The various bacterial cultures of amniotic fluid are the best method. The drug sensitivity test can be carried out after the pathogenic bacteria are determined. The disadvantage of this method is that it takes too long, at least several days to give the bacteria culture. As a result, if the drug sensitivity test is performed, the time is longer.
2. Subclinical IAIS
Subclinical IAIS usually does not have the above-mentioned clinical IAIS performance, including typical symptoms, signs, leukocytosis, etc., premature labor, IAIS, reproductive system inflammation or the presence of premature or early water break in this pregnancy is very useful for further diagnosis of subclinical IAIS Important, the following methods are usually required to clearly diagnose subclinical IAIS.
(1) Amniocentesis check:
1 Check items: There are many items and methods for amniotic fluid for IAIS, including the content of glucose in amniotic fluid, the number of white blood cells in amniotic fluid, the determination of leukocyte esterase concentration, the leukocyte aspiration test, IL-6 in the amniotic fluid, GCSF, MMP-8. , PG and TNF and other cytokines and changes in inflammatory mediators, Gram staining of amniotic fluid, amniotic fluid bacterial culture and amniotic fluid PCR technology, combined with clinical application, the principle of choosing which method to apply is that the method should be as fast as possible, Sensitive and specific requirements, but the same method is difficult to achieve at the same time, the following methods are considered to be the best detection program.
2 commonly used inspection methods:
A. Detection of cytokines and inflammatory mediators in amniotic fluid: There are many inflammatory mediators and cytokines in amniotic fluid of IAIS patients, such as IL-6, GCSF, MMP-8, PG and TNF-, etc., ELJSA method can be used. The method is rapid, simple, and sensitive, but lacks specificity. It can be used as a screening method for subclinical IAIS. The factor that has been studied for many years and can be applied to the clinic is IL-6. The normal value of amniotic fluid is <11.3ng. /ml; MMP-8, which is currently under investigation and has shown good application prospects, may be better than IL-6. After screening by this method, further pathogen examination can be performed for those who can be IAIS.
B. Gram staining of amniotic fluid and bacterial culture of amniotic fluid: It has been described in the diagnosis of previous clinical IAIS, but it is worth emphasizing that subclinical IAIS has no typical clinical manifestations, and pathogenic examination is more important for diagnosis.
C.PCR technology: The bacterial culture of amniotic fluid is a gold indicator, but only for live bacteria. Different bacterial culture conditions are different, there are false negatives, and it takes a long time. All bacteria have the same substance, bacterial ribosome 16SRNA (bacterial Ribosomal 16S RNA), amplified by PCR technology and detected to determine the presence of bacterial infections, this method is fast, sensitive, but lacks specificity, but can make up for the shortcomings of bacterial culture technology of amniotic fluid, and the two methods complement each other.
(2) Serological examination: For subclinical IAIS, there may be a variety of IAIS-related factors in pregnant women, mainly in the changes of certain factors in the serum or plasma of pregnant women, but no particularly representative markers have been found yet. .
(3) Postpartum pathology: Histopathological or bacteriological examination of postpartum pregnancy tissues such as placenta, membrane, umbilical cord and even uterus and fetus is of great significance for subclinical IAIS, with clear, affirmative and negative diagnosis. .
3. Precautions for clinical and subclinical IAIS diagnosis
(1) For the examination methods referred to in this paper, both clinical and sub-clinical can be applied, and the method is more valuable according to the above combination.
(2) Conditions for the diagnosis of clinical IAIS:
1 body temperature exceeds 37.8 ° C;
2 uterine body tenderness, malodorous vaginal secretions, white blood cells more than 15 × 109 / L, pregnant women heart rate more than 100 times / min, fetal heart rate more than 160 times / min;
3 can be confirmed by satisfying 2 of the conditions 1 and 25.
(3) The bacterial culture of amniotic fluid is a gold indicator.
(4) Subclinical IAIS can be divided into two types: inflammation and infection. The former is only positive for screening tests such as IL-6 and bacteriologically negative, while the latter is bacteriologically positive.
