Pyelonephritis in pregnancy is an infectious inflammation of the interstitial tissue, the cup—pelvic and tubular apparatus of the kidneys, acute or aggravated under the influence of urodynamic disorders during pregnancy. In the acute phase, it is manifested by lower back pain, dysuria, fever, in the chronic phase it may be asymptomatic. It is diagnosed using laboratory tests of blood and urine, ultrasound of the kidneys. The basic treatment regimen involves a combination of positional drainage, antibacterial, detoxification and desensitizing therapy. In severe cases, surgical interventions are possible: pelvis catheterization, nephrostomy, kidney decapsulation, nephrectomy.
Pyelonephritis in pregnancy occurs in 3-10% of pregnant women, is the most common urological pathology complicating the course of pregnancy. Chronic forms of the disease are more often diagnosed with repeated gestations, acute — in pre-pregnant women, which is associated with a high tone of the anterior abdominal wall of an unborn woman and, accordingly, a large pressure of the pregnant uterus on the ureters. According to experts in the field of clinical urology, in every third patient, the disorder is associated with gestation, in more than half of cases pyelonephritis debuts in pregnant women, in 15% of cases — in women in labor, up to 20-30% — in the postpartum period. The urgency of timely diagnosis and treatment of pathology is associated with a high probability of developing severe obstetric and perinatal complications up to the termination of pregnancy.
Inflammatory changes in the cup-pelvic and tubular kidney systems of pregnant women occur under the influence of infectious agents. In 95% of cases of uncomplicated pyelonephritis with an established pathogen, a monoculture of the pathogen is excreted from the urine, in 5% of patients, inflammation is supported by a microbial association. Usually, the disease is caused by conditionally pathogenic microorganisms colonizing the periurethral region: 80% of patients have Escherichia coli, 10% have saprophytic staphylococcus, klebsiella, proteus, enterococci, streptococci, epidermal staphylococcus, pseudomonas, candida, chlamydia, gonococci, mycoplasmas and viruses are much less frequently detected. According to obstetrics studies, pathogenic microflora in urine is not detected in 0.5-30% of pregnant women.
Experts have identified a number of predisposing and provoking factors that contribute to a faster penetration of pathogens and their spread through the organs of the urinary system in the gestational period. The risk group consists of patients with abnormalities of the kidneys, ureters, urolithiasis, diabetes mellitus, as well as women belonging to socially unprotected populations. The probability of developing pyelonephritis in pregnant women is significantly increased:
- Changes in urodynamics during gestation. Under the influence of progesterone and compression of the ureters by the growing uterus, 80% of healthy pregnant women have an expansion of the pelvis, cups, ureteral ducts. In late gestational periods, the urethral sphincter weakens. The situation is aggravated by the acceleration of glomerular filtration against the background of weakening of ureteral peristalsis, decreased bladder tone, hemodynamic disorders in the cup-pelvic apparatus.
- Asymptomatic bacteriuria. Conditionally pathogenic flora is seeded from the urine of 4-10% of patients, but there are no clinical signs of inflammatory processes. Since urine is a suitable medium for the reproduction of microorganisms, against the background of its stagnation and reflux in the urinary organs, 30-80% of women with bacteriuria activate saprophytic flora, acute pyelonephritis develops. An additional risk factor is previously transferred urological inflammation.
- Infectious genital and extragenital pathology. Infection of urine with an ascending spread of the pathogen is possible with vulvitis, colpitis, endocervicitis, bacterial vaginosis. In some cases, the pathogen enters the renal tissue hematogenically from the foci of chronic infections with their latent course or carrier. High bacteremia is promoted by immunosuppression, which occurs at the end of the gestational period due to an increase in the level of glucocorticoids.
The main way of spreading the pathogens of pyelonephritis in pregnancy is ascending infection. Anatomical and functional changes of the urinary organs during pregnancy contribute to stagnation of urine, increased hydrostatic pressure in the bladder, ureters, pelvis and, as a consequence, the occurrence of vesicoureteral, ureteral-pelvic, pyelotubular and pyelovenous reflux. First, microorganisms colonize the lower parts of the urinary tract — the urethra and bladder. Then, due to existing refluxes, they spread to the level of the renal pelvis, adhere to the urothelium and penetrate into the kidney tissue, causing an acute inflammatory process. Much less often, infection occurs hematogenically.
To systematize the forms of pyelonephritis in pregnancy, pathogenetic and clinical criteria are used that reflect the features of the development and course of the disease. The proposed classification is used to select the optimal tactics of pregnancy and childbirth, predicting possible complications. Obstetricians-gynecologists and nephrologists distinguish the following variants of pyelonephritis of pregnant women:
- By pathogenesis: primary and secondary. Inflammation is considered primary if it has arisen on an intact morphological basis. Secondary pyelonephritis is preceded by obstruction in anatomical defects, dysembriogenetic kidney lesions, dysmetabolic nephropathies.
- Downstream: acute and chronic. Acute inflammation occurs in 2-10% of cases mainly during the first pregnancy and is characterized by violent clinical symptoms. The chronic develops gradually (latent form) or becomes a continuation of the acute (recurrent manifest form).
- By period: exacerbations, partial and complete remission. Exacerbation is characterized by active symptoms that appear when the renal tissue is affected. With partial remission, the reverse development of symptoms is noted, with full — clinical and laboratory signs of pyelonephritis are absent.
The process is more often right—sided, less often left-sided or two-sided. Depending on the nature of pathological changes, serous, diffuse, purulent focal (destructive) and apostematous forms of inflammation are distinguished. The most severe variants of pyelonephritis of the gestational period are abscess and carbuncle of the kidney. When systematizing the disease, it is important to take into account the functional state of the kidneys, which may be preserved or impaired.
In first—time pregnant women, signs of the disease usually appear at 4-5 months of gestational age, with repeated pregnancy – at 6-8 months. The most typical symptom of pyelonephritis is intense pain on the side of the lesion, such as renal colic, which occurs in the lumbar region and radiates to the lower abdomen, groin, external genitals, inner thigh. In the third trimester, pain is less intense, manifestations of dysuria prevail. Acute inflammation is characterized by a sudden onset and pronounced intoxication syndrome — weakness, significant hyperthermia, chills, joint and muscle pain. Latent chronic forms are often asymptomatic and are detected in the laboratory.
The occurrence of Pyelonephritis in Pregnancy complicates the course of pregnancy and worsens its prognosis. The disease poses a threat to both the woman and the fetus. One of the frequent obstetric complications of pyelonephritis of pregnant women in the second trimester is a combined form of gestosis with the appearance of edema, increased blood pressure, the appearance of proteinuria, changes in the fundus vessels, gross violations of capillary architectonics and pulmonary hypertension. The risk of the threat of termination of pregnancy, spontaneous abortion, premature birth increases due to increased excitability of the uterus against the background of severe pain syndrome and fever. Anemia often develops due to inhibition of erythropoietin synthesis in the renal tissue.
Perinatal complications are usually caused by fetoplacental insufficiency, leading to fetal hypoxia and delayed development. With pyelonephritis, intrauterine infection of the fetus, leakage of amniotic fluid, amnionitis is more often observed. In newborns, the development of acute respiratory failure syndrome becomes more likely. Perinatal mortality reaches 2.4%. A separate group of complications of the gestational period are infectious-septic conditions associated with kidney inflammation — septicemia, septicopiemia, infectious-toxic shock. The development of pregnancy exacerbates the course of chronic pyelonephritis, leads to increased attacks of renal colic, provokes renal failure.
A feature of the diagnostic stage in case of suspected Pyelonephritis in Pregnancy is the limitation of examinations by methods that do not pose a danger to fetal development and pregnancy. During gestation, excretory urography, other radiological and radioisotope studies are not recommended to protect the child from radiation exposure. Instrumental techniques (catheterization of the bladder, ureters, renal pelvis, cystoscopy, chromocystoscopy) are used only to a limited extent due to the possible vertical drift of infection, changes in the topographic and anatomical location of the uterus and urinary organs. Laboratory and non-invasive instrumental studies are considered the leading ones:
- Blood tests. Characteristic signs of acute pyelonephritis are erythropenia, a decrease in hemoglobin, leukocytosis, neutrophilosis, a shift of the leukocyte formula to the left, an increase in ESR. Signs of hypoproteinemia, dysproteinemia are detected in the blood serum, creatinine and urea concentrations may slightly increase.
- Urinalysis. In the acute course of the disease, leukocytes and bacteria are found in large quantities in the material. The protein level in the urine is up to 1 g/l. Microhematuria is possible. Chronic pyelonephritis is characterized by an unstable isolation of bacteria and leukocyturia from 10-15 cells in the field of vision. If necessary, the study is supplemented with an analysis of Nechiporenko.
- Sowing urine on microflora. The method makes it possible to identify the pathogen, assess the degree of bacterial contamination by the quantitative content of colony-forming units (for most microorganisms, a titer of 105 CFU/ml is diagnostically significant). In the course of a bacteriological study, it is possible to determine the sensitivity of flora to antimicrobial drugs.
- Ultrasound of the kidneys. Echography is considered one of the simplest, informative and safe methods for determining the size of the kidneys, the thickness of their cortical layer, and the detection of enlarged cups and pelvis. With this method, concomitant urological pathology is well diagnosed — anatomical malformations, stones, hydronephrosis, benign and malignant neoplasia.
As additional methods of examination, Zimnitsky and Rehberg tests can be recommended, aimed at assessing the functional capabilities of the kidneys, ultrasound of the renal vessels, thermal imaging, liquid crystal thermography. In acute pyelonephritis of the gestational period, differential diagnosis is carried out with appendicitis, acute cholecystitis, hepatic or renal colic, aggravated peptic ulcer of the stomach or duodenum, food poisoning, influenza. According to the indications, consultations are prescribed by a urologist, surgeon, gastroenterologist, hepatologist, infectious disease specialist.
The main objectives of therapy for inflammation of the collector systems of the kidneys are the relief of clinical symptoms, the fight against the infectious agent that caused the disease, the improvement of the passage of urine, the elimination of its stagnation, the prevention of possible complications. The standard treatment regimen for a pregnant woman with pyelonephritis usually includes such groups of drugs as:
- Antibacterial agents. Empirical antimicrobial therapy is prescribed until the results of tests for flora sensitivity are obtained. In the first trimester, inhibitor-protected penicillins are recommended, from the second trimester, the use of cephalosporins, macrolides is allowed. During the entire gestational period, the use of fluoroquinolones is prohibited, in the I and III trimesters — sulfonamides. Subsequently, antibiotic therapy is corrected taking into account the data of bacterial seeding. A combination with herbal uroantiseptics is possible.
- Detoxifying and desensitizing drugs. Infusion therapy with intravenous drip administration of low-molecular dextrans, albumin, water-salt solutions is actively used to remove toxic metabolic products that accumulate in case of impaired renal function. In order to prevent possible allergic reactions to the administration of antibacterial drugs, antihistamine agents are used (non-selective and selective histamine receptor blockers, mast cell membrane stabilizers, etc.).
An important role in the treatment of pyelonephritis is played by positional drainage therapy aimed at restoring the passage of urine – a position on a healthy side or a knee-elbow position is recommended for a pregnant woman. To accelerate the effect, the introduction of antispasmodic agents is possible. In the absence of results, the pelvis is catheterized through a ureteral stent, catheter, percutaneous puncture or open nephrostomy. To influence individual links of pathogenesis, angioprotectors, saluretics and nonsteroidal anti-inflammatory drugs are prescribed, which inhibit the secretion of inflammatory mediators and reduce pain.
Surgical treatment is indicated in the presence of purulent-destructive variants of the disease (apostematosis, abscess, carbuncle). Preference is given to organ—preserving operations – opening of abscesses, excision of carbuncles, decapsulation of the affected organ. In exceptional cases, with a high threat of severe infectious and septic complications, nephrectomy is performed. In most cases, pregnancy with pyelonephritis can be preserved. The indication for termination of gestation is a complication of the disease with severe gestosis, acute renal failure, severe fetal hypoxia. The optimal method of delivery is natural childbirth with the cover of antispasmodic drugs to prevent occlusion of the ureters. Caesarean section is performed strictly according to obstetric indications due to the increased likelihood of infectious complications after surgery. After childbirth, early rising is recommended to improve the outflow of urine, prolonged sulfonamides may be prescribed.
Prognosis and prevention
The outcome of pregnancy is determined by the peculiarities of the course of the disease. The prognosis is most favorable in patients with acute pyelonephritis that occurred during the gestational period. The frequency of major obstetric complications in this case does not exceed the indicators in healthy pregnant women, but the risk of intrauterine infection of the child increases. With the exacerbation of chronic uncomplicated pyelonephritis, which debuted before pregnancy, gestation is complicated by 20-50% more often, but with adequate therapy it can be preserved. The combination of a chronic form of the disease with arterial hypertension or renal insufficiency makes carrying a child problematic. Prevention of pyelonephritis in pregnancy involves early registration in a women’s clinic, timely detection of bacteriuria, correction of diet and motor activity to improve urine passage, sanitation of foci of chronic infection.