Initially, doctors did not pay much attention to gastrointestinal symptoms in patients with COVID-19. Fever and respiratory syndrome were monitored. A more prolonged observation period revealed gastrointestinal disorders to be an important element of the new coronavirus infection. In scientific publications, a stable term appeared — gastrointestinal coronavirus disease 2019. The tropism of the SARS-CoV-2 virus to the epitheliocytes of the gastrointestinal tract, the presence and long-term persistence of the virus in the feces were found. The frequent detection of gastrointestinal symptoms in infected patients, the frequent involvement of the liver and pancreas in the pathological process determine the importance of clinical and laboratory assessment of the state of the digestive system due to its undoubted impact on the status, course, and the overall disease prognosis. Based on the analysis of scientific publications, the article presents the results of the latest observations regarding the development of a new disease, its diagnosis, treatment options using modern drugs when combined with dyspeptic syndrome and other gastroenterological symptoms. The role of the use of standards, in particular the clinical recommendations of the Ministry of Health of Russia, is emphasized. 

Iron deficiency anemia remains a significant problem in pediatric practice with its prevalence of 6–40% in the Russian Federation. Oral iron supplementation is the most common first-line treatment especially in outpatient setting. Despite adequate efficacy of oral supplementation, the problem of its side effects and, primarily, gastrointestinal toxicity remains. This review examines the issue of the potential effect of iron supplementation on gut microbiota composition, presents data from studies in animal models and in clinical studies. 

The relevance of the study is due to the high incidence of postural control impairment in patients with neurological diseases and lack of common approaches to their diagnosing in children. In this article we show the main stages in the formation of postural control and mechanisms of balance maintaining in childhood. We assessed the information content of existing clinical scales used to study components of postural balance in children in clinical practice. Also, we studied the diagnostic significance of functional methods for assessing postural control. Particular attention we paid to the study of the diagnostic significance of computer posturography (stabilometry) and accelerometry. We identified the main clinical and functional diagnostic markers of postural imbalance in children of different age and nosological groups. Further research in this area will make it possible to develop the most objective criteria for impaired postural control in childhood, which will increase the effectiveness of treatment and rehabilitation measures. 

The open arterial duct has a pathological significance in premature newborns. Closure of the ductus arteriosus is a complex process that includes functional and anatomical closure.

Purpose. To identify the features of arterial duct remodeling in premature newborns.

Material and methods. We conducted a retrospective clinical and morphological analysis of 35 deceased premature newborns. During their lifetime, all children were examined using clinical and laboratory-instrumental methods. In all cases, autopsies of deceased children were performed with a complex of morphological studies of the arterial duct.

Results. It has been established that the open arterial duct in premature newborns plays an important role in increasing respiratory failure. It also necessitates the appointment and conduct of invasive respiratory therapy. The functioning of the arterial duct is facilitated by low partial pressure and blood oxygen saturation levels. Morphofunctional features of arterial duct remodeling were revealed. A positive correlation was established between the indicators of the gas composition of the child’s blood and the thickness of the duct wall.

Conclusion. Risk factors for an open arterial duct in premature newborns are the age of the mother over 35 years, threatened miscarriage, prenatal discharge of amniotic fluid, gestational diabetes mellitus, fetoplacental insufficiency, and severe asphyxia at birth. Morphological changes in the form of thickening of the endothelial layer and the formation of intimal pillows, fragmentation and focal necrosis of the internal elastic membrane with the accumulation of mucoid matter, proliferation and migration of smooth muscle cells into the subendothelial space reflect the processes of remodeling of the arterial duct. 

The research revealed features of platelet and plasma hemostasis indicators in children born before 32 weeks with hemorrhagic disorders in the early neonatal period, a method for predicting the development of intraventricular hemorrhage was developed.

Material and methods. 132 premature newborns were examined, a detailed clinical blood test, a coagulogram with the determination of: activated partial thromboplastin time, prothrombin time, thrombin time, prothrombin index, fibrinogen content, D-dimer were performed on 1–3 days of life. The main group consisted of 58 children with hemorrhagic disorders, the comparison group included 74 children without hemorrhagic disorders.

Results. Risk factors for the formation of hemorrhagic disorders in the early neonatal period were established: a lower gestational age of the child, lower Apgar scores at the end of the first and fifth minutes of life, the need for the introduction of an exogenous surfactant, and the use of higher concentrations of oxygen-air mixture during respiratory therapy. The features of hemostasis indicators in deep-premature newborns with hemorrhagic disorders in the early neonatal period were revealed: a lower number of platelets in the blood and higher platelet granularity, higher activated partial thromboplastin time, and a decrease in the prothrombin index. Based on the data obtained, a new method for predicting the formation of intraventricular hemorrhage in deeply premature newborns is proposed based on determining the concentration of total Ca2+ in the blood and the average concentration of platelet components. The results of this study can be used in intensive care units for newborns. Conclusion. The implementation of the obtained results in practice will help timely assess the state of hemostasis in deeply premature newborns to predict the development of intraventricular hemorrhages in the early neonatal period. 

Purpose. This study aims at assessing the association of the development and clinical course of arterial hypotension in premature newborns, depending on the polymorphism of the genes of predisposition to hypertension.

Material and methods. The study design is prospective, controlled, single-center, and non-randomized. Genomic DNA samples were studied in premature newborns (n = 199), as well as a population sample of adults (n = 100). Newborns with arterial hypotension (n = 23) formed the study group, patients without it (n = 100) formed the comparison group. Loci with already known association with the development of arterial hypertension and coronary heart disease were selected for analysis: AGT (rs4762), AGTR1 (rs5186), ACE (Ins\Del), ADRB1 (rs1801253), ADD1 (rs4961), CYP11B2 (rs1799998), eNOS (rs1799983), eNOS (rs1549758), eNOS (rs2070744). The distribution of allele frequencies between the studied groups of individuals was compared.

Results. Premature babies are significantly more likely to be carriers of the allele with the AGT gene. In newborns with arterial hypotension, we additionally revealed a more frequent occurrence of dominant alleles of the eNOS gene, and children with the SS genotype of the eNOS gene required longer vasopressor therapy. Conclusion. The carriage of risky alleles of genes predisposing to arterial hypertension, not only does not increase the risk of arterial hypotension in premature newborns, but also may, in the case of carriage of mutant alleles of the eNOS rs1549758 gene, contribute to less prolonged vasopressor therapy. 

Timely diagnosis of brain lesions in infants is important for preventing the development and progression of neurological diseases.

Purpose. The study aimed at investigation of neurospecific laboratory parameters in children of 1 year of age with structural changes in the brain.

Material and methods. The clinical and laboratory examination of 50 children of 1 year of age, born at full term, was carried out. Serum concentrations of neurotrophic growth factor (BDNF), fractalkine (CX3CL-1), monocytic chemotactic protein (CCL2), trigger receptor expressed on myeloid cells-1, 2 (TREM-1, TREM-2), transforming growth factor-ȕ1 (TGF-ȕ1), nerve growth factor-ȕ (ȕ-NGF), visinin-like protein-1 (VILIP-1), vascular endothelial growth factor (VEGF), glycosylation end product receptor (sRAGE), interleukin (IL)-6, IL-18, and tumor necrosis factor Į (TNF-Į).

Results. Predictors of brain damage in full-term infants have been identified. The level of TGFB-1 in children with structural changes in the brain exceeded that of the control group by 1.4 [1.1; 1.6] times, the level of AntiGRIN2A — 1.6 [1.1; 2.0] times, which makes it possible to consider these parameters as biomarkers of brain damage.

Conclusion. Based on the results obtained, an additional laboratory examination of children who have undergone ante- and intranatal hypoxia is recommended, including the determination of the level of neurodamage biomarkers such as: TGFB-1 and AntiGRIN2A. This study will contribute to the timely detection of disorders of the central nervous system and the initiation of therapy to prevent the development and progression of neurological pathology in childhood. 

Craniosynostosis is a craniofacial anomaly, characterized by premature fusion of one or more of the cranial sutures. Each suture and their combination correspond to a special type of deformation.

Purpose. The study aimed at indicating the difficulties of early diagnostics of various forms of the craniosynostosis and evaluating the quality of treatment of patients with this disease depending on their age.

Material and methods. A survey of parents with craniosynostosis who were treated at the Almazov National Medical Research Centre in 2018–2019 was conducted. The parents of 107 patients were surveyed. The main objectives of our research were: to evaluate the timeliness of diagnosis of craniosynostosis at primary health care at patient’s place of residence; to compare the methods of diagnosis verification and to present the results of the parents’ subjective assessment of the results of surgical treatment at the early and long-term postoperative period.

Results. The median age of children when they were diagnosed with craniosystosis was 5 months, the median age of patients when they underwent a surgical treatment was 16 months. The median duration of the catamnesis was 6 months. We revealed that the preliminary diagnosis was established by a neurologist and pediatrician only in 21% of cases. Only at 28% of cases, children were directed to neurosurgeon, who confirm the diagnosis. In 38 (35.3%) cases, patient’s parents independently sought medical advice. The diagnosis was verified by the results of the computer tomography in 55% of patients. on because primary care specialists due to the lack of primary care specialists’ awareness about the diagnosis of craniosynostoses and attempts at long-term monitoring and conservative treatment. The timeliness of detection of craniosynostosis in the newborn period and in the|first month of life can significantly improve the cosmetic and functional outcomes of the disease. 

Connective tissue dysplasia affects the course of pyelonephritis.

Purpose. The study aimed at identifying the features of chronic pyelonephritis in children with different dysplastic phenotypes.

Material and methods. The study included 108 children aged 6–17 years with chronic pyelonephritis and connective tissue dysplasia. They were divided into 3 groups with Marfan-like, Ehlers-like, and unclassifiable phenotypes.

Results. It was shown that the groups differed in the frequency of occurrence and types of structural disorders of urinary system, which affected the need for surgical treatment.

Conclusion. Considering the dysplastic phenotype allows for a personalized approach to the patient. 

In Russia, the QAA-25 questionnaire is used to quantify the adherence to treatment of adult patients. The accumulated experience of its use made it possible to identify several cohorts of respondents, including adolescents, whose characteristics required special adaptation of the formulations of a number of questions.

Purpose. The study aimed at modifying the questionnaire for quantitative assessment of treatment adherence QAA-25 for adolescents aged 15–17 years and evaluate it according to the criteria of validity and the measure of consent.

Material and methods. In a descriptive one-stage study with the participation of 108 high school students at secondary schools in Omsk, the level of adherence to treatment was determined according to the QAA-25 scale, using traditional and alternative formulations of individual questions, with the formation of a modified scale and an assessment of its constructive and factor validity and a measure of consent.

Results. Applying various options for testing alternative questions, the possibility and expediency of using them to assess the adherence to treatment of adolescents, including separately evaluated subsamples of male and female individuals, was shown. 94% of respondents rated alternative questions as “more acceptable,» 5% of respondents «did not notice significant differences,» and 1% of respondents rated them as «less acceptable.» The QAA-25 scale modified for adolescents demonstrated good structural and internal validity (α = 0.818, α_st = 0.857), with high reliability (consistent exclusion of scale items preserves the validity of the questionnaire in the range of 0.793–0.858) and almost perfect agreement (κ = 1.000).

Conclusion. The modified QAA-25 questionnaire is recommended to be used to assess the adherence to treatment and potential adherence to treatment of adolescents who have reached the age of 15 but have not reached the age of 18, both for research purposes and when making decisions related to the provision of medical care and the organization of preventive measures. 

Liver cirrhosis in children and adolescents is a consequence of a variety of chronic liver diseases, metabolic disorders, and genetic diseases. In infants, cirrhosis is most often due to biliary atresia and genetic-metabolic diseases, while in older children it usually occurs as a result of autoimmune hepatitis, Wilson’s disease, alpha-1 antitrypsin deficiency, and primary sclerosing cholangitis. Symptoms of cirrhosis in children and adolescents are not specific. In pediatric patients, the first sign of cirrhosis may more often be low weight gain, weakness, loss of appetite, low-grade fever, as well as more specific signs: transient jaundice, mild pruritus, epistaxis, heaviness in the right hypochondrium, changes in liver density on palpation, hyperbilirubinemia, hyperenzymemia, etc. Complications of pediatric cirrhosis are similar to those observed in adult patients and include gastrointestinal bleeding caused by esophageal varices, ascites, and spontaneous bacterial peritonitis. In pediatric practice, special attention should be paid to nutritional correction in liver cirrhosis since children have higher requirements for protein and micronutrients for growth and development. Treatment of cirrhosis-induced portal hypertension in children and adolescents is mainly based on methods developed for adults. The article deals with diagnostic and differential diagnostic aspects of the terminal stage of liver disease in children. The therapeutic management of patients with cirrhosis of the liver and acute renal failure is based on support of various organ functions. Hemodialysis/ plasmapheresis may serve in some patients as an interim therapy before liver transplantation. The indications for liver transplantation and problems arising after surgery are considered. 

Около 15% всех нарушений мочеиспускания приходится на довольно опасное нарушение уродинамики — дисфункциональное мочеиспускание, или детрузорно-сфинктерную диссинергию, при котором отсутствует возможность полной релаксации сфинктера и потоку мочи препятствует высокое давление в уретре. Детрузорно-сфинктерная диссинергия — наиболее распространенный вариант функциональной инфравезикальной обструкции. Проявляется продолжительным по времени опорожнением мочевого пузыря с необходимостью напряжения брюшного пресса, а также периодически возникающим неконтролируемым резким перерывом потока мочи. Активность сфинктера уретры при детрузорно-сфинктерной диссинергии обусловлена нарушением функции микционного центра Варолиева моста, в норме обеспечивающего согласованную работу детрузора и наружного сфинктера уретры, а также классических рефлексов мочеиспускания (с 7-го по 11-й), обеспечивающих фазу опорожнения, — нарушается последовательность их активации. Для преодоления внутриуретрального давления во время микции создается высокое внутрипузырное давление. Нестабильное состояние сфинктера создает турбулентный и реверсивный ток мочи по уретре. Эти факторы приводят к развитию ретроградного инфицирования мочевых путей, нарушению оттока мочи из лоханок почек и мочеточников, определяя риск развития почечной недостаточности. В статье подробно описана патологическая физиология детрузорно-сфинктерной диссинергии, объяснены клинические проявления с позиции патогенеза и дано представление о возможных результатах уродинамических исследований при данной патологии. 

Purpose. To give a quantitative and qualitative assessment of the results of prenatal diagnosis of critical congenital heart defects in the Republic of Kazakhstan based on the treatment of newborns at the head cardiac surgery center.

Methods. A retrospective analysis of the medical records of 511 newborns with critical congenital heart defects treated at the National Research Cardiac Surgery Center (NRCSC) in 2012–2019 was performed. The proportion of those operated on was 474/511 (92.8%). The studied parameters were the presence of prenatal diagnosis of critical congenital heart defects (yes/no); prenatal diagnosis formulation; postnatal diagnosis formulation; discrepancy between pre- and postnatal diagnoses (yes/no); for a prenatally diagnosed newborn — the gestational age at the time of the diagnosis and the region where the diagnosis was firstly made.

Results. Prenatally, 297/511 (58.1%) newborns were diagnosed. The rate of discrepancies between pre- and postnatal diagnoses was 62/288 (21.5%). According to the timing of the prenatal diagnosis, newborns were distributed as follows: first trimester screening — 20/272 (7.4%), second trimester screening — 139/272 (51.1%), third trimester screening — 113/272 (41.5%). Up to 22 weeks of gestation, 71/272 (26.1%) patients were diagnosed. Among the newborns treated at the NRCSC, the proportion of those diagnosed prenatally in different regions of the Kazakhstan varies from 20% to 100%.

Conclusions. 1) Prenatal diagnosis of critical congenital heart defects is carried out in all regions of Kazakhstan, providing an acceptable level of detection; 2) in half of the cases, critical congenital heart defects are diagnosed during the second screening, however, there is an experience of their accurate detection as early as during the first screening; 3) individually, doctors of ultrasound diagnostics in Kazakhstan apply an extended protocol for examining the fetal heart; 4) a significant proportion of fetuses diagnosed before the 22nd week of gestation shows the choice of families in favor of carrying of a pregnancy when a critical congenital heart defects is detected; 5) the greatest difficulty for prenatal diagnosis is presented by patients with total anomalous pulmonary veins return. 

The purpose of this work is to demonstrate the possibility of applying the case method for teaching the diagnosis of orphan diseases on a specific example. The article presents the possibilities of virtual diagnostics of a rare clinical case — a combination of two hereditary diseases: Angelman and Wiedemann—Steiner syndromes. The authors have developed a web application that allows you to reproduce the process of differential diagnostics using multimedia technologies. At each stage of virtual diagnostics, it is necessary to analyze the information received so far about the patient, determine the plan for further examination, refer the patient for consultations to specialists and form diagnostic hypotheses. To assess the correctness of the choice of the doctor’s actions, questions are provided. As a result of passing the case, an integral score is calculated and displayed on the screen — the sum of points for correct answers. Repeated passage of virtual diagnostics usually increases the quantitative criterion, and most importantly helps to consolidate the knowledge necessary for proper diagnosis. An interactive clinical case can be used in the process of training students at medical universities as an additional tool, as well as to improve the skills of pediatricians who can meet with this pathology in their practice. The use of the case-based learning in the educational process allows not only to conduct the learning doctor through the stages of the virtual diagnostic process but also to assess the correctness of the choice of the option of their actions, to explain the wrong decision in a particular situation. 

Any system, including the health care system, maintains stability, integrity and adapts to the requirements of evolution due to the changes introduced into it at the stages of development. None of the health systems are flawless and all are improving in various ways. The article provides an overview of the stages of development of healthcare in the Russian Federation based on an analysis of the regulatory legal framework over the past thirty years. As an illustration, an analysis of the organization of medical care for children with cancer was carried out. 

The novel SARS-CoV-2 coronavirus infection is predominantly asymptomatic or presenting few symptoms in children, and life-threatening complications are rare. In most cases, symptoms of ARVI are observed, such as fever, cough, myalgia, or weakness, which are milder than in adult patients. In addition, most laboratory and radiographic findings in children with COVID-19 are nonspecific. However, some children may develop prolonged forms of COVID-19, as well as long-term symptoms (post-COVID syndrome) after the illness, which significantly affect the quality of life. There are different data regarding the prevalence and duration of long-term effects of a new coronavirus infection in children. The most common symptoms following COVID-19 in children/teens are fatigue, lack of concentration, and muscle pain. The review presents the latest literature data on the duration and course of COVID-19 in children. It should be remembered that long-term symptoms could affect the physical, social, and psychological well-being of children and adolescents in the future. 

Since the beginning of the pandemic, the new coronavirus infection has been regarded primarily as a respiratory disease. By now, it has become obvious that COVID-19 is a systemic infectious process with multiple organ damage. Having affinity for ACE-2 receptors, the virus can infect the cells of the respiratory tract, as well as the cells of the cardiovascular and nervous systems and smooth muscle structures of various organs. Expression of ACE-2 by enterocytes of the small intestine makes the gastrointestinal tract vulnerable in COVID-19 disease and leads to the manifestation of symptoms of gastrointestinal damage, which is often observed in clinical practice. Gastrointestinal symptoms usually include anorexia, nausea, vomiting, diarrhea, and abdominal pain, which can occur both at the onset and during the disease. Several mechanisms are described to explain these changes in COVID-19. 

Regular physical activity has a positive effect on blood pressure, but despite this fact, arterial hypertension in athletes, including children and adolescents, is a common problem. It is known that an increase in blood pressure is the most common cardiac symptom detected on pre-competition examination or physical performance testing. The risk factors for hypertension in young athletes are generally similar to those in the child and adolescent population as a whole, but some risk factors exist that are specific to athletes. The article discusses the possibilities of admittance of young athletes to sports competitions and the main aspects of drug and non-drug therapy. 

A premature baby in need of resuscitation after birth is exposed to damaging factors that affect the entire body, including the kidneys. The review considers the stages of development and identifies the main anatomical and physiological features of the kidneys in premature babies. The main risk factor for the development of pathology associated with immaturity of the kidneys in preterm infants is imperfect glomerular and tubular functions of the kidneys, a large capillary surface of the kidneys, high renal blood flow, imperfect regulation of the acid-base balance, and the ability to concentrate, which become untenable under the influence of external loads. Any damaging factor in the antenatal period in premature infants, considering the anatomical and physiological characteristics and the imperfect compensatory response from the kidneys, can permanently change the structure of the kidneys, which will lead to the development of chronic kidney disease in the future. Proper management of premature newborns, considering the anatomical and physiological characteristics of the kidneys, will significantly reduce the risk of severe complications and mortality among premature newborns, and improve the long-term clinical prognosis in such children. 

Periventricular hemorrhage is bleeding from the subependymal germinal matrix, which results in severe motor disorders, mental and speech developmental delay.

Purpose. The study aims to evaluate risk factors, the trends of neurological disorders, and the outcomes of neonatal periventricular hemorrhage in children whose mothers were on gravidary anticoagulant and/or antiplatelet therapy.

Material and methods. The study examined 160 newborns with PVH: Group I — 53 (37.9%) children born from pregnancy on the background of antiplatelet and/or anticoagulant therapy for hypercoagulation syndrome; Group II — 87 (62.1%) children born from pregnancy on the background of antiplatelet and/or anticoagulant therapy to treat degree 1A uteroplacental blood flow disorders; Group III — 20 children born from pregnancy without corticosteroids and antiplatelet and/or anticoagulant therapy. All newborns underwent clinical and neurological examination and neurosonography; data on somatic and obstetric anamnesis were obtained from accompanying medical records.

Results. In children of Groups I and II a more severe condition of newborns with periventricular hemorrhage at birth was noted, a slower dynamics of restoration of muscle-postural tone and the pace of psychomotor development were observed compared to children in Group III. In Groups I and II a high incidence of epilepsy (5.7%) and cerebral palsy (6.4%) by 12 months of corrected age was revealed compared with the population.

Conclusion. Gravidary anticoagulant and antiplatelet therapy might be considered as a risk factor for the development of intracranial hemorrhages and severe neurological disorders: epilepsy, cerebral palsy, mental and motor developmental delays. 

The article analyzes the features of the neurological status, characterizes group differences in motor functions in children with autism spectrum disorders depending on the presence and severity of delayed psychological and speech development.

Material and methods. The analysis of data on the neurological status of children with autism spectrum disorders was based on 51 patients records for the period from 2016 to 2021; 43 boys (84%) and 8 girls (16%) aged 3 to 10 years. All patients were divided into 2 groups according to the criterion of the presence or absence of a severe delay in psychological and speech development. The first group included children with severe forms of delayed psychological and speech development — 23 (45%), the second — 28 (55%) patients with mild forms or without delayed psychological and speech development.

Results. The children in the first group were characterized by the predominance of diffuse muscular hypotension (96%); stereotypies manifested in movements looking like «wings» (22%), other stereotyped movements (48%); disorders such as echolalia, ataxia, pyramidal insufficiency syndrome, and strabismus were equally common in both groups.

Conclusion. Analysis of the data showed the predominance of several neurological disorders in children with autism spectrum disorders who have a severe delay in psychological and speech development and made it possible to identify neurological characteristics of children with autism spectrum disorders regardless of the level of psychological and speech development. 

Disturbance of the microbiocenosis of the nasal cavity and oropharynx in children with congenital cleft palate presents serious therapeutic difficulties. Pathobionts colonizing the upper respiratory tract and chronic adenoiditis pose a threat of acute purulent otitis media and chronic otitis media with effusion. The authors studied nasal and oropharyngeal mucosal dysbiosis in patients before elective uranoplasty and the effect of dysbiotic manifestations on the condition of the middle ear in the postoperative period. The results of microbiological examination of 80 swabs from the nasal cavity and oropharynx in patients with congenital cleft palate were analyzed. Among the culture-positive results in patients in clinical and laboratory remission of ENT-infections dysbiosis of 2–3 degrees prevails, the presence of bacterial-bacterial and bacterial-fungal associations is often noted, the predominance of gram-negative microflora is noted. There was an increase in the frequency of perforations of the tympanic membrane in the presence of bacterial and fungal associations, the appearance of retraction pockets in the presence of gram-negative microflora, the relationship between grade 3 dysbiosis and the appearance of purulent otitis media after uranoplasty were revealed.

Conclusion. Disturbance of microbiocenosis in patients with congenital cleft palate before uranoplasty requires the inclusion of a microbiological study in the preoperative preparation schedule and a personalized approach to perioperative antibiotic prophylaxis. 

COVID-19 has a risk of thrombotic complications. Serotonin plays an important role in pathogenesis of thrombosis.

Purpose. To evaluate level of serotonin and its metabolite in the blood of children with COVID-19.

Methods. This study included 72 children aged 3 to 17 years. Of these, 43 patients (mean age 11.2 ± 4.8 years) diagnosed with COVID-19 without comorbidities made up the study group, 29 healthy children (mean age 11.8 ± 3.8 years) — the control group. Concentration of serotonin and its metabolite (5-HIAA) in the blood was determined using high performance liquid chromatography with electrochemical detection. Computed tomography data were used to determine severity of lung damage.

Results. In our study children with COVID-19 aged 3 to 17 years had significantly higher serotonin and its metabolite levels compared to the control group. Concentration of serotonin in plasma in main group was 20–30 times higher than in the same-age control. The 5-HIAA/serotonin ratio in children with COVID-19 is significantly lower than in the control group. Levels of serotonin and 5-HIAA in children with COVID-19 depending on the severity of CT-scan lung damage showed no significant differences.

Conclusion. Serotonin and its metabolite levels in plasma of children with COVID-19 is significantly increased. It may be related to platelet hyperactivation in SARS-CoV-2 infection and increased risk of thrombosis, which requires further research. 

Children with cerebral palsy are at high risk of developing nutritional disorders: malnutrition, osteopenia, micronutrient deficiency. This is facilitated by motor disorders, restriction of actual nutrition, the presence of concomitant drug therapy, and metabolic features.

Purpose. The study aims at evaluation of laboratory markers of nutritional status in children with cerebral palsy.

Material and methods: for a comprehensive assessment of nutritional status disorders, a cross-sectional analytical study of 175 children with cerebral palsy was carried out. Laboratory studies included the determination in blood of: total protein, glucose, ALT, AST, total and direct bilirubin, cholesterol, creatinine, urea, vitamins A, E, B12, folic acid, magnesium, phosphorus, calcium, serum iron, zinc, total iron-binding ability, ferritin, 25-OH vitamin D, parathyroid hormone.

Results. Only in 5 (3%) children all the studied laboratory parameters were within the reference values. The most frequently observed in children with cerebral palsy were: 25-OH vitamin D insufficiency/deficiency in 68% of children, a decrease in folic acid levels in 32%, an increase in vitamin B12 in 32%, a decrease in cholesterol in 26% and creatinine in 16.6%, a decrease in phosphorus in 14.5%, serum iron in 12.4% and an increase in magnesium in 10.3%.

Conclusion. The detected deficiency of some indicators is most likely associated with an unbalanced actual diet of patients with cerebral palsy, although the reduced intake of certain vitamins and microelements was not always reflected in their blood concentrations (vitamin A, E, magnesium, calcium). The levels of zinc, vitamin B12 and A did not decrease in any of the examined children, which casts doubt on the recommendations of ESPGHAN experts in terms of prescribing them to all children with cerebral palsy in routine clinical practice. 

Hemolytic-uremic syndrome includes a triad of symptoms: microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. Given the progressive course of hemolytic-uremic syndrome, up to the terminal stage of renal failure, it is necessary to search for early markers of renal tissue damage as prognostically significant factors in the development of nephrosclerosis, which is of particular importance in childhood to optimize the management of such patients. The analysis of the literature data demonstrates the actual role of serotonin and platelet-mediated effect of serotonin on fibroinflammatory processes in kidney vessels. Thus, changes in the serotonergic system in patients already at the onset of hemolytic-uremic syndrome are of great interest in order to develop new diagnostic approaches that allow optimizing early diagnosis and slowing down the progression of renal damage in this category of patients. These studies will expand knowledge about the role of the serotonergic system in the formation of chronic kidney disease in children with hemolytic-uremic syndrome. 

Purpose. To study the features of potassium metabolism in young athletes based on the analysis of its concentration in biological substrates.

Material and methods. The study involved 123 children aged 12 to 17 years. Four groups were formed: control (n=26), swimmers (n=33), hockey players (n=45), fencers (n=19). Samples were studied using inductively coupled plasma atomic emission spectrometry. Saliva and hair were used as substrates for analysis.

Results. As a result of our study, it was found that in the control group, the content of potassium in saliva was significantly higher than in young athletes of all groups (p<0.001). At the same time, it was also shown that the content of potassium in the hair of people professionally involved in sports is significantly higher than that of the control group (p><0.01). The use of correlation analysis made it possible to identify a negative statistically significant relationship between the indicators of potassium concentrations in saliva and in hair (R=–0.72; p><0.001). Conclusion. The results obtained indicate the formation of potassium content in saliva and hair are probably related and may reflect the peculiarities of mineral metabolism processes in young athletes. Further research is needed to determine the mechanisms of mineral metabolism in young athletes. Key words: children, young athletes, potassium, physical development, deficiency of bioelements>˂0.001). At the same time, it was also shown that the content of potassium in the hair of people professionally involved in sports is significantly higher than that of the control group (p˂0.01). The use of correlation analysis made it possible to identify a negative statistically significant relationship between the indicators of potassium concentrations in saliva and in hair (R=–0.72; p˂0.001).

Conclusion. The results obtained indicate the formation of potassium content in saliva and hair are probably related and may reflect the peculiarities of mineral metabolism processes in young athletes. Further research is needed to determine the mechanisms of mineral metabolism in young athletes. 

To date, the association of SARS-CoV-2 infection with the reactivation of herpes viruses has been determined. This has been proven not only by the results of laboratory studies, but also by a clinically confirmed subsequent manifestation of the herpetic process. The article describes a clinical case of Epstein–Barr viral and cytomegalovirus infections reactivation after COVID-19. The child was diagnosed with anicteric form of hepatitis of herpetic etiology. Hepatitis, moderate anicteric form. During treatment, the patient’s condition improved. Complete clinical recovery with normalization of the activity of alanine and aspartate aminotransaminases occurred 1 month after the onset of the disease, but the level of lymphocytes and gamma-glutamyl transpeptidase still remained moderately elevated. According to the ultrasound of the abdominal organs, the size of the liver returned to normal. The presented case illustrates that mixed infections are a quite possible situation during the COVID-19 pandemic, which must be taken into account when working with such patients. 

The article presents a case of cytomegalovirus-associated carditis in a 5-month-old child. Carditis proceeded in an arrhythmic form and was manifested by frequent ventricular extrasystoles. An increase in the activity of creatine-phosphokinase was noted in the blood. The isolation of cytomegalovirus DNA from the blood, as well as IgM and IgG to cytomegalovirus, made it possible to associate the development of carditis with IgG to cytomegalovirus. Carditis in a child proceeded without signs of heart failure. After diagnostic and therapeutic procedures, the child was discharged home. This case shows that one of the possible causes of carditis in children is cytomegalovirus, which necessitates testing for markers of active cytomegalovirus infection. In this age group, it is possible to register both congenital and acquired variants of infection with heart damage, having different treatment regimens and prognosis. 

Fibrous dysplasia is a rare anomaly of bone tissue development, in which it is replaced by fibrocystic tissue. A clinical case of a patient with a craniofacial polyossal form of fibrous dysplasia is presented. At the age of 13, a child had a constant intense headache, which was accompanied by dizziness, tinnitus, cognitive impairment, deformity of the frontal region and lower jaw on the right, local pigmentation in the neck and face (coffee-and-milk-like stains). Brain tomography and osteoscintigraphy visualized a volumetric formation in the right half of the skull bones, in which fibrotic dysplasia was revealed during histological examination.

Conclusion. To establish this diagnosis, a combination of pain syndrome with deformation of the facial part of the skull and histological examination is important. 

Herpetic infections are distinguished by a diverse clinical picture — this is primarily the so-called «recurrent respiratory diseases» or a recurrent variant of a chronic infectious process in the form of a so-called «mononucleosis-like syndrome,» characteristic of almost every «herpetic nosology,» persistent subfebrile condition, and febrile condition. Often, against the background of herpetic infections, various kinds of exanthems manifest, and this is not only a vesicular rash during infection with the herpes simplex virus. In practice, pediatricians often have to deal with other types of exanthems, one way or another associated with herpes infections. The article discusses 2 clinical observations of relatively unusual manifestations of chronic herpetic infections accompanied by erythema in patients aged 16 years. Photo documents of the dynamics of the skin process and laboratory parameters against the background of antiviral therapy are presented. 

The article presents the results of dynamic monitoring of a patient with Cornelia de Lange syndrome. The patient was born with archetypal facial features, multiple stigmas of dysembriogenesis, pre– and postnatal growth retardation and perinatal pathology of the brain in the form of spastic tetraparesis. Later, the child progressed with psychomotor development delay, hearing and vision disorders. Based on the conducted examination, consultations of specialists, including genetics, the diagnosis of «Cornelia de Lange syndrome» was established. To make this diagnosis, specific facial features in combination with additional criteria are sufficient. 

The diagnosis of genetic disorders is always difficult. Early detection of Angelman syndrome is complicated by the similarity of its clinical manifestations with other diseases. The purpose of the study was to describe the clinical manifestations in children with Angelman syndrome in order to identify early and characteristic clinical signs. In the study of patients, it was revealed that the hereditary history was aggravated in one patient, the obstetric history — in all women. Clinical manifestations debuted in children at an early age, only in one patient from birth. In all children, changes were recorded on the electroencephalogram and magnetic resonance imaging of the brain. The patients were consulted by a geneticist. Awareness of the medical community contributes to the timely detection of signs of the disease and the establishment of a diagnosis. The sooner the diagnosis is established, the higher the chances of providing the patient with effective care. 

MEHMO syndrome (OMIM: 300148; ORPHA: 85282) is a disease appears by mental retardation, epilepsy seizures, hypogonadism, microcephaly, and obesity. Pathology is associated with mutations in the EIF2S3 gene located on the X chromosome and leads usually to serious disability of patients. The article presents a clinical observation of the case of the syndrome in two male cousins with microcephaly, manifested by a complex of endocrinopathies (hyperinsulinemic hypoglycemia, multiple adenohypophysis hormone deficiency) and accompanied by severe neurological abnormalities (epilepsy, spastic tetraparesis, optic nerve atrophy). The complexity of the diagnostic due to the rarity of this syndrome, is described. 

Assessment of motor development is an important part of the study of the neuropsychic development of children, which is carried out by a pediatrician during preventive examinations. To identify the causes of motor disorders, in addition to studying the anamnesis, it is necessary to conduct a physical examination of the child with the appointment of additional research methods. It is important to remember that developmental delay does not always indicate the presence of any disease but requires dynamic monitoring. However, if they progress, then these patients are more likely to be diagnosed with specific neuromuscular disorders. In this case, the pediatrician should pay attention to the neurological status of the child, assess visual acuity and hearing. At the same time, one should not forget that motor disorders are often combined with a general developmental delay (mental retardation) of the child. Fasciculation of the tongue, loss of motor skills, organomegaly, coarsening of facial features, increased levels of creatine phosphokinase (more than 3 times higher than normal), respiratory failure, in the presence of general weakness, a sharp deterioration in the child’s condition, accompanied by lethargy, vomiting, development of convulsive syndrome, disorders detected on MRI of the brain, are alarming symptoms that require urgent intervention by specialists (neurologist, genetics). Also, some hereditary (chromosomal and monogenic) diseases are often combined with the development of motor disorders. The best results are achieved if the early diagnosis of diseases accompanied by movement disorders is carried out using an interdisciplinary approach. 

Short bowel syndrome is a rare, chronic, debilitating, and potentially life-threatening condition in which loss of intestinal absorption capacity deprives children of the ability to absorb sufficient nutrients from the food they consumed. The authors describe regional experience of treating children with short bowel syndrome, which includes conservative and surgical approach, with an analysis of the leading causes, prognostic factors, timing of achieving intestinal autonomy, complications and catamnesis.

Purpose. The study aims at analyzing cases of short bowel syndrome in children in order to improve the provision of medical care for children in the Republic of Tatarstan and the nearest regions.

Material and methods. Single-center, retrospective study was conducted of 22 cases of children with short bowel syndrome who received treatment in the surgical department for young children in the State Autonomous Healthcare Institution Children’s Republican Clinical Hospital of the Ministry of Health of the Republic of Tatarstan for the period September 2014 till November 2021.

Results. The most common cause of intestinal resection in the study group were: congenital malformations in 7 children (32%), necrotizing enterocolitis in 5 children (23%), small intestine malrotation (Ladd’s bands) in 4 children (18%), mesenteric thrombosis in 4 (18%), Hirschsprung’s disease in 2 children (9%). By the end of the first year after diagnosis, intestine self-regulation was achieved in 17 children. The mortality rate was 9%.