Pyelonephritis in pregnancy

Pyelonephritis in pregnancy (especially with purulent-destructive lesions of the kidneys) in recent years is registered much more often than in pregnant women in other countries.

The increase in the prevalence of pyelonephritis in pregnancy and its complications is associated with unfavorable environmental and social factors that create conditions for reducing the protective mechanisms of a pregnant woman. Their breakdown is also facilitated by overwork, avitaminosis, decreased immunity, concomitant infectious diseases and other factors.

[1], [2], [3],

Causes of the pyelonephritis in pregnancy

Pyelonephritis in pregnancy refers to diseases that have adverse effects, both on the mother's body and on the developing fetus. Its occurrence can lead to such serious complications as purulent-necrotic lesions of the kidney and sepsis. With pyelonephritis, pregnancy increases the likelihood of premature birth, miscarriage, intrauterine fetal death and other obstetric complications. At examination in the remote terms after the transferred pyelonephritis at pregnancy at many women find out a chronic pyelonephritis, nephrolithiasis, a nephrosclerosis, an arterial hypertensia, etc.

Acute pyelonephritis can occur during pregnancy, childbirth and the nearest postpartum period, which is why this complication is most often called acute gestational pyelonephritis.

Isolate acute gestational pyelonephritis of pregnant women (found most often), parturient women and puerperas (postpartum pyelonephritis).

Up to 10% of pregnant women with acute pyelonephritis suffer from purulent-destructive forms of the disease. Among them, carbuncles predominate, their combination with apostems and abscesses. The majority of pregnant women develop unilateral acute pyelonephritis, while the right-sided process is found 2-3 times more often than the left-sided process. Currently, pyelonephritis ranks second in frequency among extragenital diseases in pregnant women. Pyelonephritis during pregnancy is more likely to affect women during the first pregnancy (70-85%) and primiparous than the miscarriages. This is explained by the lack of mechanisms of adaptation to immunological, hormonal and other changes inherent in the body of a woman during the gestational period.

More often pyelonephritis during pregnancy occurs in the II and III trimesters of pregnancy. Critical periods of its development are 24-26th and 32-34th weeks of pregnancy, which can be explained by the peculiarities of the pathogenesis of the disease in pregnant women. Less often, pyelonephritis during pregnancy manifests during childbirth. Pyelonephritis puerperas usually occurs on the 4-12th day of the postpartum period.

The causes of pyelonephritis in pregnancy are diverse: bacteria, viruses, fungi, protozoa. The most common acute pyelonephritis during pregnancy is caused by conditionally pathogenic microorganisms of the intestinal group (Escherichia coli, Proteus). In most cases, it occurs as a continuation of childhood pyelonephritis. Activation of the inflammatory process often occurs during puberty or at the beginning of sexual activity (when defloration cystitis occurs and pregnancy). The etiologic microbial factor is the same for all clinical forms of pyelonephritis in pregnancy, and a history of urinary tract infection in more than half of women suffering from pyelonephritis in pregnancy. 

Asymptomatic bacteriuria found in pregnant women. - one of the risk factors for the development of the disease. Directly bacterial agent does not cause acute pyelonephritis, however, bacteriuria in pregnant women can lead to pyelonephritis in pregnancy. Asymptomatic bacteriuria is noted in 4-10% of pregnant women, and in 30-80% of the latter they detect acute pyelonephritis. Bacteriuria in pregnant women is one of the risk factors for pyelonephritis in children born. It is dangerous for the mother and fetus, since it can lead to premature birth, pre-eclampsia and fetal death. It is known that the urine of a pregnant woman is a good breeding ground for bacteria (especially Escherichia coli). This is why the timely detection and treatment of bacteriuria is of particular importance in preventing possible complications.

The frequency of asymptomatic bacteriuria in pregnant women is affected by the sexual activity of a woman before pregnancy, the presence of various malformations of the urinary tract, a violation of personal hygiene.

[4], [5], [6], [7]

Pathogenesis

In the pathogenesis of pyelonephritis, various factors play a role in pregnancy, while the mechanisms of hemo- and urodynamic disorders may vary depending on the timing of pregnancy. An important role in the pathogenesis of pyelonephritis in pregnancy belongs to disorders of urodynamics of the upper urinary tract, the causes of which can be both hormonal and compression factors. In the early stages of pregnancy, a change in the ratio of sex hormones with subsequent neurohumoral effects on alpha and beta-adrenoreceptors, leading to a decrease in the tone of the upper urinary tract, is noted. The leading pathogenetic factor of pyelonephritis in pregnancy in later terms of pregnancy is considered the mechanical pressure of the uterus on the ureters.

In addition to the above mechanisms, an important role in the development of pyelonephritis in pregnancy is played by urodynamic changes in the upper urinary tract, vesicoureteral reflux, immune system depression and genetic predisposition.

Dilatation of CHLS is observed from 6-10th week of pregnancy and is observed in almost 90% of pregnant women. It is at this time that hormonal dissociation occurs: estrogen and estradiol in the blood substantially increase by 7-13 weeks, and progesterone - by 11-13th week of pregnancy. At 22-28th week of pregnancy, the concentration of glucocorticoids in the blood increases. It is established that the effect of progesterone on the ureter is similar to beta-adrenergic stimulation and leads to hypotension and dyskinesia of the upper urinary tract. With an increase in the level of estradiol, alpha-receptor activity decreases. Because of a violation of the equilibrium of hormones, there is an upset urodynamics of the upper urinary tract, the tone of the CLS and ureters decreases and their kinetic response slows down.

Violation of the outflow of urine due to atony of the urinary tract leads to the activation of pathogenic microflora, and the possible vesicoureteral-ureter reflux contributes to the penetration of microorganisms into the interstitial material of the medulla of the renal parenchyma.

Thus, in pregnant women, inflammatory changes in the kidneys are secondary and are associated with a violation of urodynamics of the upper urinary tract due to hormonal imbalance.

The change in the concentration of estrogens promotes the growth of pathogenic bacteria, especially the E. Coli, which is caused by a decrease in the function of lymphocytes. In this case, pyelonephritis, as such, may not be, only bacteriuria occurs. In the future, against the background of disturbances in the urodynamics of the upper urinary tract, pyelonephritis develops. The increase in the concentration of glucocorticoids in the blood at the 22nd-28th week of pregnancy contributes to the activation of the previously begun latent inflammatory process in the kidneys.

In late pregnancy, the urinary outflow from the kidneys is affected by compression of the enlarged uterus of the lower parts of the ureters (especially the right one). Disorders of urodynamics of the urinary tract in the second half of the time, when most often acute pyelonephritis occurs, the majority of the second is explained by dynamic anatomical-topographic relationships between the anterior abdominal wall, the uterus with the fetus, the pelvic bone ring and ureters.

The compression of the ureter enlarged and rotated around the longitudinal axis to the right by the uterus promotes the dilatation of the upper urinary tract and the development of pyelonephritis. It was found that the expansion of the upper urinary tract occurs already at the 7th-8th week. Pregnancy, when there is still no mechanical effect of the pregnant uterus on the ureter. It is believed that the greater the degree of dilatation of the upper urinary tract, the higher the risk of pyelonephritis in pregnancy. 80% of pregnant women and 95% of primiparas observe a more or less pronounced expansion of the calyx-pelvis and ureter to a cross with iliac vessels.

Violation of the urodynamics of the upper urinary tract in pregnant women is often associated with the presentation of the fetus. For example, compression of ureters is noted in most pregnant women with fetal presentation and is not recorded with the gluteal or transverse position of the fetus. In some cases, a violation of the passage of urine from the upper urinary tract in pregnant women can be associated with the syndrome of the right ovarian vein. In this case, the ureter and the right ovarian vein have a common connective tissue membrane. With an increase in the diameter of the vein and an increase in the pressure in it, during pregnancy, the right ureter is compressed in the middle third, leading to a disturbance in the outflow of urine from the kidney. Expansion of the right ovarian vein may be due to the fact that it at right angles into the renal vein. The right ovarian vein syndrome accounts for the more frequent development of acute right-sided pyelonephritis in pregnant women.

Bladder-ureteral-pelvic reflux is one of the pathogenetic mechanisms of pyelonephritis in pregnancy. Bladder-and-pelvis reflux is noted in almost 18% of clinically healthy pregnant women, while in pregnant women who previously transferred acute pyelonephritis, the prevalence is more than 45%.

Studies of recent years have shown that the incompetence of the vesicoureteral and the occurrence of vesicoureteral reflux in pregnant women is caused by both hormonal discrep- tion and damage to the basal membranes of the leiomyocytes of the urinary tract at all levels. The rupture of the calyx is a consequence of the renal calculus and urinary infiltration of the interstitial tissue of the kidney and urinary sinus resulting from this, accompanied by acute impairment of blood circulation in the kidney and hypoxia of the organ, which also creates a favorable ground for the development of pyelonephritis.

Normally, when the bladder is filled naturally, before the physiological urge to urinate, the tension of the abdominal press and the emptying of the bladder do not cause dilatation of the cup-and-pelvis system, i.e. There is no reflux.

According to ultrasound, the following types of vesicoureteral reflux in pregnant women are distinguished:

• with the tension of the abdominal press and the filling of the bladder before the appearance of a physiological urge or after urination, the expansion of the cup-and-pelvic system is noted, but within 30 min after the evacuation of the digestive system, the kidney is completely reduced;
• with the tension of the abdominal press and the filling of the bladder before the appearance of a physiological urge or after urination, the expansion of the cup-and-pelvic system is noted, but within 30 minutes after evacuation of the cup-pelvis system, only half of the original size is emptied;
• the bowel-and-pelvis system is extended to urination, and after it the retention is further increased and to its original dimensions after 30 minutes does not return.

During pregnancy, there is a reorganization of the lymphoid organs, which is associated with the mobilization of suppressor cells. Pregnancy is accompanied by an involution of the thymus gland, whose weight reduction by 3-4 times compared to the initial one already occurs by the 14th day of pregnancy. Hypotrophy of the gland persists for more than 3 weeks after childbirth.

Significantly decreases not only the number of T cells, but also their functional activity, which is associated with direct and indirect (through the adrenal glands) effect on it of steroid sex hormones. In pregnant women suffering from acute pyelonephritis, a decrease in the number of T-lymphocytes and an increase in the B-lymphocyte count is more pronounced than in women with a normal pregnancy. The normalization of these indicators in the process of treatment can serve as a criterion of recovery. In pregnant women with acute pyelonephritis, not only the decrease in phagocytic activity of leukocytes and the phagocytic index is noted, but also the inhibition of nonspecific protective factors (decrease in the content of complement and lysozyme components).

In the near postpartum period, not only the previous risk factors for the development of acute pyelonephritis persist, as during pregnancy, but new ones also appear:

• a slow contraction of the uterus, which is capable of creating a compression of the ureters 5-6 days after the birth;
• pregnancy hormones that persist in the mother's body up to 3 months after childbirth and support dilation of the urinary tract;
• complications of the postpartum period (incomplete placental abruption, bleeding, hypo- and atony of the uterus);
• inflammatory diseases of the genital organs:
• urological complications of the early postpartum period (acute urinary retention and prolonged catheterization of the bladder).

Quite often, acute postpartum pyelonephritis is found in women who have had acute gestational pyelonephritis during pregnancy.

[8], [9], [10], [11]

Symptoms of the pyelonephritis in pregnancy

Symptoms of pyelonephritis during pregnancy in recent years has changed, which makes early diagnosis difficult. Symptoms of acute pyelonephritis of pregnant women are due to the development of inflammation against the background of impaired urinary outflow from the kidney. The onset of the disease is usually acute. If acute pyelonephritis develops until 11-12 weeks of gestation, then patients have the common symptoms of inflammation (fever, chills, sweating, high body temperature, headache). They note weakness, adynamia, tachycardia. In later periods of pregnancy, there are local symptoms of pyelonephritis in pregnancy (pain in the lumbar region, painful urination, feeling of incomplete emptying of the bladder, macrogematuria). Pain in the lumbar region can irradiate to the upper abdomen, inguinal region, large labia. 

The hectic increase in temperature that occurs in patients at certain intervals of time can be related to the formation of purulent foci in the kidney and bacteremia. At birth, the symptoms of pyelonephritis in pregnancy are veiled by the body's response to the birth act. Some women with acute pyelonephritis of the puerperium are mistakenly diagnosed with endometritis, perimetritis, sepsis, appendicitis. Usually, it occurs on the 13-14th day after delivery and is characterized by tension, pain in the muscles of the right ileal region, radiating to the lower back, high fever, chills, fuzzy symptoms of irritation of the peritoneum, which often serves as an excuse for appendectomy.

Diagnostics of the pyelonephritis in pregnancy

The use of many methods of diagnosis of acute gestational pyelonephritis during pregnancy is limited. Especially it concerns the x-ray examination. Radiation load on the fetus should not exceed 0.4-1.0 rad. However, excretory urography even in this mode poses a serious threat to it. It is known that when irradiated from 0.16 to 4 rad (average dose - 1.0 rad), the risk of developing a child's leukemia almost doubles, and the risk of developing malignant neoplasms in newborns is three times or more. Excretory urography is used in pregnant women only in exceptional cases - with extremely severe forms of pyelonephritis during pregnancy. Usually, it is prescribed only for those patients who, according to medical indications, will be aborted.

X-ray and radioisotope methods of research are recommended to be used only in the nearest postpartum period for the diagnosis of postpartum pyelonephritis.

Laboratory tests are the obligatory method of diagnosing pyelonephritis in pregnancy, their complex includes a general analysis of urine and blood, bacteriological analysis of the blood with the definition of the degree of bacteriuria and the sensitivity of the isolated organisms to antibiotics, the determination of the functional activity of thrombocytes

The most informative and objective criteria for the severity of acute pyelonephritis are indicators of the coagulating system of blood and immunological tests. Leukocyte index of intoxication and the content of medium-molecular peptides.

A method for calculating the temperature of the kidneys by their microwave radiation is proposed. Which is completely harmless to the mother and fetus and can be used as an additional method of diagnosing pyelonephritis during pregnancy.

Instrumental methods of diagnosing pyelonephritis in pregnancy, including catheterization of ureters and renal pelvis, are rarely used. It is considered dangerous even for pregnant women to perform a suprapubic urinary bladder puncture to take urine for analysis, which is associated with a possible change in the topographic and anatomical relationships of the urinary and genital organs during pregnancy.

It is not recommended to have a catheterization of the bladder, since any instrumentation on the urethra in the bladder is fraught with a drift of infection from the anterior to the posterior part of the urethra and the bladder. However, if a ureteral catheter or stent is proposed for treatment purposes, then preliminary ureteral catheterization is advisable to obtain urine from the affected kidney (for selective examination).

The leading role in the diagnosis of pyelonephritis in pregnancy belongs to ultrasound of the kidneys. It allows not only to determine the degree of dilatation of the upper urinary tract and the state of the renal parenchyma. But also to detect the indirect signs of vesicoureteral reflux. When ultrasound is determined halo of rarefaction around the kidney, limiting its mobility. Reduction of dilatation of the upper urinary tract in various positions of the body. The ultrasonographic signs of pyelonephritis in pregnancy include an increase in the size of the kidney, a decrease in the echogenicity of the parenchyma, the emergence of foci of reduced echogenicity of the oval-circular form (pyramid), and a decrease in the mobility of the kidney.

Sometimes an increase in the thickness of the parenchyma of the kidney is noted up to 2.1 ± 0.3 cm and an increase in its echogenicity. With carbuncles and abscesses, heterogeneity of the parenchyma is determined in combination with unevenness of its thickness, foci of echogenicity with a diameter of 1.7-2.7 cm. Absence of mobility of the kidney with deep breathing and expansion of the CLS. Modern ultrasonic devices provide the possibility of quantitative evaluation of echosity, which is widely used in the diagnosis of pyelonephritis in pregnancy.

Another method of quantitative evaluation of Dopplerography with the definition of intensity and pulsativity index, systolic-diastolic ratio of volumetric flow velocity and renal artery diameter.

Diagnosis of destructive forms of pyelonephritis during pregnancy presents significant difficulties and is based on clinical, laboratory and ultrasound data, analyzed in dynamics. The leading criterion for the severity of the condition is the severity of intoxication. Disturbing signs pointing to destructive changes in the kidney are considered constantly high body temperature, resistant to antibiotic therapy. Increasing the concentration of creatinine and bilirubin in the blood. In the carbuncle, the kidneys visualize the large focal areas of the parenchyma with increasing or decreasing echogenicity (depending on the development phase of the process) and deformation of the external contour of the kidney. The kidney abscess is defined as a rounded formation with a content of reduced echogenicity.

[12], [13], [14], [15], [16], [17]

Treatment of the pyelonephritis in pregnancy

In recent years, the frequency of complicated forms of pyelonephritis in pregnancy requiring surgical treatment remains high. When examining women in the long-term after the transferred pyelonephritis during pregnancy, often detect chronic pyelonephritis, nephrolithiasis, arterial hypertension, chronic renal failure and other diseases, so the problems of prevention, timely diagnosis and treatment of pyelonephritis in pregnancy are very relevant.

Treatment of pyelonephritis in pregnancy is carried out only in stationary conditions. Early hospitalization of patients contributes to better treatment outcomes.

Medical measures for pyelonephritis in pregnancy begin with the recovery of outflow of urine from the renal pelvis. Apply positional draining therapy, for which the pregnant woman is laid on a healthy side or in the knee-elbow position. Simultaneously, prescribe antispasmodics: baralgin (5 ml intramuscularly), drotaverin (2 ml intramuscularly), papaverine (2 ml 2% solution intramuscularly).

In the absence of the effect of the therapy, catheterization of the pelvis is performed using a ureteral catheter or stent for urinary diversion. Sometimes a percutaneous puncture or an open nephrostomy is performed. Percutaneous nephrostomy has certain advantages over internal drainage:

• form a well-controlled short external drainage channel;
• Drainage is not accompanied by vesicoureteral reflux:
• care of drainage is simple, there is no need for repeated cystoscopy to replace it.

At the same time percutaneous nephrostomy is associated with a certain social maladjustment. Against the backdrop of recovery of outflow of urine from the pelvis, antibacterial treatment, detoxification and immunomodulating therapy are carried out. When prescribing antimicrobials it is necessary to take into account the peculiarities of their pharmacokinetics and possible toxic effects on the mother and fetus. In purulent-destructive forms of pyelonephritis, pregnancy is performed by operative treatment, more often - organ-preserving (nephrostomy, decapsulation of the kidney, excision of carbuncles, opening of abscesses), less often - nephrectomy.

When choosing a method for draining the upper urinary tract with pyelonephritis during pregnancy, the following factors should be considered:

• duration of attack of pyelonephritis;
• features of microflora;
• degree of dilatation of the cup-and-pelvis system;
• presence of vesicoureteral reflux;
• terms of pregnancy.

The best results of drainage of the urinary tract are achieved with a combination of positional and antibacterial therapy, satisfactory - with the stent, and the worst - with a catheterization of the kidney by a common ureteral catheter (may fall out, which requires repeated repetition of the procedure).

Against the background of a restored outflow of urine from the kidney, conservative treatment of pyelonephritis during pregnancy, which includes etiological (antibacterial) and pathogenetic therapy, is carried out. The latter includes non-steroidal anti-inflammatory drugs (NSAIDs), angioprotectors and saluretics. It is necessary to take into account the peculiarities of pharmacokinetics of antibacterial drugs, their ability to penetrate the placenta, into breast milk. In the treatment of pyelonephritis in the puerperium, it is possible to sensitize the newborn due to the ingestion of antibiotics with the mother's milk. For women with pyelonephritis, it is preferable to prescribe natural and semisynthetic penicillins (deprived of embryotoxic and teratogenic properties) and cephalosporins during pregnancy. In recent years, macrolide antibiotics (roxithrombin, clarithromycin, dzhozamycin, etc.) have been used more widely.

Pipemidic acid (urotractin), belonging to the quinolone group. Only in a small amount penetrates the placenta. The content of the drug in the milk of the puerperas 2 hours after taking the dose of 250 mg does not exceed 2.65 μg / ml and then gradually decreases and after 8 hours it is not determined at all. Aminoglycosides should be administered with caution and not more than ten days. Sulfanilamides are not recommended for use throughout pregnancy. Gentamicin is administered with caution, since it is possible to damage the VIII cranial nerve in the fetus.

Treatment of complicated forms of pyelonephritis during pregnancy of pregnant women remains one of the most difficult tasks for urologists and obstetrician-gynecologists. There is no unified classification of complications of the disease. In addition, there was a tendency to an increase in the prevalence of purulent-destructive forms of pyelonephritis in pregnancy. Among the possible causes of which can be identified frequent infection with highly virulent gram-negative microorganisms, immunodeficiency states, late diagnosis of the disease and untimely initiation of treatment.

An important component of detoxification therapy for complicated forms of pyelonephritis in pregnancy is the use of extracorporeal methods of detoxification. For example plasmapheresis. Advantages of the method: ease of implementation, good tolerability of patients, no contraindications to its use in pregnant women. With plasmapheresis, the deficit of cellular and humoral immunity is eliminated. After the first session, most patients normalize body temperature, reduce the severity of clinical and laboratory signs of intoxication, improve well-being; there is a stabilization of the patients, which makes it possible to perform surgical intervention with minimal risk.

In the complex treatment of pyelonephritis in pregnancy, it is recommended to include ultraviolet irradiation of autoblood. The most effective use of this method earlier (before the transition of the serous stage of the disease into a purulent one).

Indications for surgical treatment of pyelonephritis in pregnancy:

• ineffectiveness of antibiotic therapy for 1-2 days (increasing leukocytosis, increasing the number of neutrophils in the blood and ESR, increasing the concentration of creatinine);
• obstruction of the urinary tract caused by calculi;
• inability to restore urodynamics of the upper urinary tract.

Only the performance of early and adequate in volume operations in pregnant women with purulent-destructive pyelonephritis is able to stop the infectious inflammatory process in the kidney and ensure normal development of the fetus.

The choice of the method of operation depends on the clinical course of pyelonephritis in pregnancy: the degree of intoxication, the damage of other organs, macroscopic changes in the kidneys. Timely implementation of surgery in most cases allows you to save the kidney and prevent the development of septic complications.

With purulent-destructive changes limited to 1-2 segments of the kidney, nephrostomy and kidney decapsulation are considered to be an adequate method of surgical treatment. With widespread purulent-destructive organ damage and severe intoxication, which threatens the life of the pregnant and fetus, the most justified nephrectomy. In 97.3% of pregnant women, the use of various surgical interventions made it possible to achieve a clinical cure for purulent-destructive pyelonephritis.

Interruption of pregnancy with pyelonephritis during pregnancy is rare. Indications for it:

• fetal hypoxia;
• acute renal failure and acute hepatic insufficiency;
• intrauterine fetal death;
• miscarriage or premature birth;
• hypertension in pregnant women;
• severe gestosis (with unsuccessful therapy for 10-14 days).

Recurrence of the disease is noted in 17-28% of women with inferior or late-onset treatment. For the prevention of recurrence of the disease, regular follow-up of women who have had pyelonephritis during pregnancy, a thorough examination after delivery, recommended timely diagnosis of various urological diseases, prevent complications, and plan future pregnancies.