Introduction. Despite the dominance of mild traumatic brain injury (mTBI) in the structure of TBI, the biochemical parameters of mild brain damage in brain concussions have not been sufficiently studied. This fact makes it difficult to predict the outcomes of concussions that are part of the mild form of TBI. Aim of the work: identify changes in markers of brain damage in children’s blood who underwent mTBI with an emphasis on brain concussions, and compare the indicators with a group of children with moderate TBI (mdTBI).
Materials and methods. One hundred thirty six children were examined, including 35 children with concussion (15 points on the Glasgow Coma Scale (GCS)), 65 children with mTBI (13–14 points on the GCS) and 36 children with mdTBI (9–12 points on the GCS). In the first 1–2 days after TBI, the content of such markers of brain damage as glial protein S100b, acidic fibrillary protein GFAP, αII-spectrin (spectrin breakdown product — SBDP-145), 2 types of autoantibodies (aAT) to glutamate receptors (GluRc) — NMDA (NR2) and AMPA (GluR1) subtypes, degradation products of these receptors — peptides corresponding to the N-terminal regions of NMDA and AMPA GluRc (NR2 and AMPA1 peptides), as well as the content of nitric oxides (NOx) (NO₂– + NO₃–) and 3-nitrotyrosine (NT). The concentrations of these compounds in blood serum/plasma were determined by enzyme immunoassays.
Results. In the first days after TBI, a significant proportion of children with mTBI showed an increase in the content of oxidative stress markers (NOx, NT) and a significant increase in the level of aAb to NMDA GluRc in the blood. In children with mdTBI, indicators of brain damage (S100b, GFAP, αII-spectrin, NOx, and NMDA GluRc degradation products — NR2 peptides) exceeded those in children with mTBI. On the contrary, the level of aAb to NMDA GluRc and the degradation products of AMPA GluRc — AMPA 1 peptides had maximum values in the group of mTBI in children with brain concussions.
Conclusion. It has been shown that in many children with mTBI (GCS = 14–15), most of the indicators are at the upper limit or exceed the upper limit of the normal values, which indicates a different degree of brain response to mild traumatic stress. In children with concussion, a high level of aAb to NMDA GluRc against the background of a low content of their degradation products, NR2 peptides, in the first days after TBI may indicate more pronounced compensatory mechanisms aimed at reducing NMDA GluRc hyperstimulation in mTBI. At the same time, a higher content of AMPA 1 peptides in children with concussions may be the initial signs of diffuse axonal damage.
Contribution: Sorokina E.G., Reutov V.P., Semenova Zh.B. — concept, design and writing the text; Semenova Zh.B., Sorokina E.G., Karaseva O.V. — collection and processing of the material; Smirnov I.E. — editing the text. All co-authors — approval of the final version of the article, responsibility for the integrity of all parts of the article.
Acknowledgments. The study had no sponsorship.
Conflict of interest. The authors declare no conflict of interest.

Received: January 18, 2026
Accepted: February 10, 2026
Published: February 27, 2026

Introduction. Liver transplantation is the only treatment option for liver fibrosis/cirrhosis. Cytomegalovirus (CMV) is the most common virus affecting liver transplant outcome and can lead to both graft loss and recipient death. Objective. To assess the incidence, causes, and course of CMV infection in children undergoing orthotopic liver transplantation in the early and late postoperative periods and the effectiveness of a combination of preventive and therapeutic measures for its control in a regional setting.
Materials and methods. An analysis of the incidence, causes, and course of CMV infection was conducted in 43 pediatric patients undergoing liver transplantation.
Results. Preoperative CMV carriage was detected in 14 patients. These patients had no viral replication in the blood and, therefore, no special therapeutic preparation with antiviral drugs was performed prior to surgery. Twenty-nine potential liver transplant recipients had CMV infection prior to surgery and received ganciclovir at a therapeutic dose until two negative blood PCR results were obtained (tests were performed 10 days apart) during preparation for surgery. Postoperatively, CMV infection was detected at various times in 39 children: asymptomatic viremia in 25, CMV syndrome in 5, and CMV disease in 9.
Conclusion. Following liver transplantation, CMV infection can develop in almost 100% of children, both early and late post-transplant. CMV infection can be controlled with flexible drug prophylaxis/therapy regimens combined with laboratory monitoring of infection activity (PCR), provided patients are maximally compliant with therapy, undergo dynamic monitoring, and are closely supervised by various medical specialists.
Contributions: Beloussova T.V., Nikulina A.B., Loskutova S.A. — concept and design of the study; Nikulina A.B. — collection and processing of data; Nikulina A.B., Loskutova S.A. — statistical processing of data; Nikulina A.B., Beloussova T.V., Loskutova S.A. — writing the text; Beloussova T.V., Nikulina A.B., Loskutova S.A., Porshennikov I.A. — editing the text. All co-authors — approval of the final version of the article, responsibility for the integrity of all parts of the article.
Acknowledgments. The study had no sponsorship.
Conflict of interest. The authors declare no conflict of interest.

Received: January 20, 2026
Accepted: February 10, 2026
Published: February 27, 2026

Introduction. Antenatal torsion of the uterine adnexa remains a challenging diagnostic entity in contemporary perinatal medicine. This is due to the rarity of the condition, the absence of pathognomonic sonographic criteria, and the lack of unified clinical management protocols.
Materials and methods. The presented clinical cases describe rare instances of antenatal torsion of the uterine adnexa in newborns. The key diagnostic findings were obtained through prenatal ultrasound examination, which revealed adnexal mass lesions. The diagnosis was subsequently confirmed intraoperatively and by pathological examination. Both patients underwent laparoscopic surgical treatment with histological verification of ovarian tissue necrosis.
Results. In both cases, patient survival was achieved; however, the adnexal structures involved in the torsion were nonviable due to the development of tissue necrosis.
Conclusion. The presented clinical cases demonstrate the need for further accumulation of experience, systematic data collection, and analysis to establish a consensus-based approach to the diagnosis and management of this condition. Such efforts will not only improve long-term outcomes but also enhance the potential for fertility preservation in affected patients, which is a critical aspect of their future health and reproductive potential. Long-term follow-up and data analysis may form the basis for developing more accurate and effective treatment strategies for antenatal torsion.
Contribution: Sibirskaya E.V., Gurskaya A.S. — research concept and design; Tikhonova T.S., Ekimovskaya E.V., Baiazitov R.R. — data analysis, development of treatment tactics, validation; Smolik L.Yu., Bogacheva A.A., Akhverdian R.A. — writing the text; Sibirskaya E.V., Gurskaya A.S. — editing the text. All co-authors — approval of the final version of the article, responsibility for the integrity of all parts of the article.
Acknowledgments. The study had no sponsorship.
Conflict of interest. The authors declare no conflict of interest.

Received: January 15, 2026
Accepted: February 10, 2026
Published: February 27, 2026

Introduction. Pleural empyema in children is a complex form of pathology. Despite the clinical successes, the tasks of individually assessing the severity of the course and predicting outcomes in children with pleural empyema remain relevant. In this regard, biomarkers reflecting the intensity of systemic inflammation and the course of convalescence in children are of particular importance. Quantitative analysis of changes in the content of these biologically active compounds makes it possible to identify patients with a high risk of complications, predict recovery course and optimize treatment tactics. Aim: to determine both the clinical efficacy of thoracoscopic treatment of pleural empyema in children and the importance of biomarkers in predicting clinical outcomes.
Materials and methods. There were examined 126 children aged 1 to 17 years with a diagnosis of acute pleural empyema who underwent inpatient treatment. The patients were divided into two groups: the main group consisted of 65 children (51.6%) who underwent video thoracoscopic intervention at an early stage, the comparison group included 61 patients (48.4%) who received treatment for pleural empyema without early thoracoscopy. The concentrations of biomarkers in the blood were determined in all patients: before surgery, 24 hours after the intervention, and on the 3rd day after surgery. Quantitative analysis of catecholamines (epinephrine, norepinephrine) was performed by high performance liquid chromatography (HPLC). The levels of cortisol, cytokines, lactate, C-reactive protein, and procalcitonin were determined by immunochemical methods. All the received data has been processed statistically.
Results. In children with pleural empyema, the blood levels of cortisol, adrenaline, and norepinephrine were significantly increased compared with the levels in the comparison group. The level of procalcitonin in the patients of the main group was increased by more than 3.5 times, which indicates the course of a severe bacterial infection. The blood concentrations of cytokines: interleukins-6, -10 and tumor necrosis factor in children with pleural empyema were also significantly increased, reflecting the course of the active inflammatory process. In patients of the main group, after performing an early video thoracoscopy, the detected lower increase in blood levels of inflammatory biomarkers indicates to effective recovery. Monitoring of changes in these biomarkers made it possible to optimize treatment and improve the prognosis of the disease.
Conclusion. The necessity of early thoracoscopic intervention and the use of biomarkers as significant criteria for optimizing the treatment of children with pleural empyema has been determined.
Contributions: Faiziev O.Ya. — concept and study design; Yusupov A.S., Akramova Kh.A., Faiziev Ya.N. — data collection and processing; Abzalova M.Y. — statistical analysis; Faiziev O.Ya. — writing the text; Yusupov A.S. — editing the text. All coauthors — approval of the final version of the article, responsibility for the integrity of all parts of the article.
Acknowledgments. The study had no sponsorship.
Conflict of interest. The authors declare no conflict of interest.

Received: January 16, 2026
Accepted: February 10, 2026
Published: February 27, 2026

Introduction. The quality of life is an integral characteristic of the vital activity, which covers in patients the social, physical, and psychological functioning. The quality of life is defined as a person’s individual relationship to their position in life (culture, values, plans and goals in this person, opportunities and degree of disorder). Aim: to determine changes in the parameters of the quality of life of children with hemorrhagic syndrome, taking into account the level of homocysteine in blood plasma.
Materials and methods. There were examined ninety seven children aged of 13–17 years. The main group consisted of 30 adolescents with clinical manifestations of hemorrhagic syndrome. The control group consisted of 67 children without signs of bleeding. The children of both groups were comparable in gender and age. The quality of life was assessed using a valid randomized questionnaire, the Pediatric Quality of Life Questionnaire PedsQL4.0 for adolescents. There were assessed following parameters of functioning: physical, emotional, social, school and psychosocial health. Based on the data obtained, the total score was calculated. All the data received has been processed statistically.
Results. The highest indicators of the quality of life were obtained in children of the control group on the scales of social and physical functioning. The indicators of quality of life in children with hemorrhagic syndrome on the background of hyperhomocysteinemia had lower scores on the scales of physical functioning (96.25 points), school functioning (84.16 points), psychosocial health (84.40 points) and overall score (86.70 points) when compared with children with hemorrhagic syndrome, whose plasma homocysteine levels was within the normal range. The maximum difference in scores when comparing children of both groups was found on the scale of social functioning (13.3 points), followed by psychosocial health (12.0 points) and emotional functioning (11.8 points).
Conclusion. According to all studied parameters the quality of life in children without hemorrhagic manifestations is significantly higher. To prevent hyperhomocysteinemia and increase QOL in children with bleeding symptoms, rational folate-vitamin correction is advisable.
Contribution: Strozenko L.А., Lobanov Yu.F. — concept and design of the study; Ponomarev V.S., Sanina О.О. — collection and processing of the material; Ponomarev V.S., Strozenko L.А. — statistical processing of the material; Ponomarev V.S., Strozenko L.А. — writing the text; Lobanov Yu.F., Skudarnov E.V. — editing the text. All co-authors — approval of the final version of the article, responsibility for the integrity of all parts of the article.
Acknowledgments. The study had no sponsorship.
Conflict of interest. The authors declare no conflict of interest.

Received: January 23, 2026
Accepted: February 10, 2026
Published: February 27, 2026

Introduction. Cystic fibrosis (CF) primary ciliary dyskinesia are hereditary diseases characterized by impaired mucociliary clearance and chronic respiratory tract involvement. 
Aim. To present current literature data on the pathogenesis of hearing loss in muco-obstructive lung diseases and detect risks of aminoglycoside ototoxicity under the modulating therapy for CF in children. There was performed an analysis of scientific literature data from international databases (Scopus, Web of Science, PubMed) and Russian scientific libraries (eLIBRARY.RU, CyberLeninka). Differences in the nature of hearing loss in СF and primary ciliary dyskinesia were established. For the primary ciliary dyskinesia there is characteristic hearing loss, whereas in CF the risk of sensorineural hearing loss persists due to the ototoxicity of aminoglycosides caused by targeted therapy. Personalized treatment and prevention of these forms of pathology in children help reduce risks, necessitating the development of specialized monitoring algorithms. The need for a differentiated approach to monitoring auditory function in patients with muco-obstructive lung diseases has been established.
Contributions: Sokolova V.N. — concept and design of the study; Sokolova V.N., Malyavina U.S., Simonova O.I. — material collection and processing; Sokolova V.N., Malyavina U.S. — writing the text; Simonova O.I., Kondratchikov D.S. — editing the text. All authors approved the final version of the manuscript and are responsible for the integrity of all parts of the article.
Acknowledgments. The study had no sponsorship.
Conflict of interest. The authors declare no conflict of interest.

Received: January 23, 2026

Accepted: February 10, 2026

Published: February 27, 2026

Introduction. Polycystic ovarian syndrome (PCOS) is a significant endocrine disorder that is especially difficult to diagnose in adolescent girls when its clinical picture is disguised as the physiological features of puberty. The key clinical manifestations of PCOS in adolescents are menstrual disorders, hyperandrogenic symptoms, and metabolic changes, which together create a high risk of adverse reproductive and somatic consequences in the future. The aim of the review is to present up-to-date data on the formation of PCOS, its pathogenesis, diagnosis, and treatment in adolescent girls. The literature was searched in the databases PubMed, eLibrary, Google Scholar, Embase. The lack of universal diagnostic criteria for PCOS leads to its overdiagnosis or underdiagnosis. The diagnostic process in adolescent girls requires special care and a dynamic approach. Significant diagnostic criteria are persistent menstrual irregularities in combination with clinical and laboratory signs of hyperandrogenism. Treatment of PCOS in adolescent girls should be comprehensive and include lifestyle modification, medication, and, if necessary, alternative approaches. The use of combined oral contraceptives, metformin and antiandrogenic drugs is carried out taking into account the individual characteristics of patients and under strict safety control. Educational and psycho-emotional programs aimed at increasing adherence to treatment and reducing the adverse impact of the disease on the quality of life are important. Timely detection and treatment of PCOS in adolescents plays an important role in the prevention of serious reproductive and metabolic complications in later life, which makes the creation of optimal approaches to early diagnosis and therapy of PCOS a priority and important task.
Contribution: Sibirskaya E.V. — concept and design; Karapetyan A.A., Chatikyan I.A. — information collection and processing; Sibirskaya E.V., Karapetyan A.A., Chatikyan I.A. —writing the text; Sharkov S.M. — editing the text. All co-authors — approval of the final version of the article, responsibility for the integrity of all parts of the article.
Acknowledgments. The study had no sponsorship.
Conflict of interest. The authors declare no conflict of interest.

Received: January 20, 2026
Accepted: February 10, 2026
Published: February 27, 2026

Objective. Ewing sarcoma is a highly metastatic form of sarcoma, the second most common primary malignant bone tumor, primarily affecting adolescents. Its extreme rarity in the cervical spine may lead to a delay in diagnosis until the tumor reaches an advanced stage and compresses the spinal cord. Initial symptoms may include neck pain and radiculopathy. These symptoms may progress rapidly, accompanied by limb weakness and bladder or bowel dysfunction, developing within days over the disease onset. A high degree of clinical suspicion is crucial for early diagnosis and treatment. The aim: To present a clinical description of a case of acute clinical manifestation of Ewing’s sarcoma extending from the second cervical vertebra.
Materials and methods. We describe a case of a 3-year-old girl without history of chronic illness or trauma. Clinical manifestations of symptoms began 6 months before the full-blown clinical picture, with mild, progressive, intermittent pain in the cervical spine, initially attributed to torticollis. Three months later, with persistent symptoms, the patient underwent a cervical spine X-ray, which at that time revealed no significant pathological changes. Approximately 6 months after onset, symptoms sharply worsened over several days, leading to severe pain, tetraparesis, and pelvic dysfunction. MRI revealed a lesion of the second cervical vertebra, affecting both the vertebral body and the posterior arch, with infiltration of the anterior epidural space, nerve root openings at the level of the second and third cervical vertebrae, and adjacent paravertebral muscles. Tumor invasion of the right vertebral artery encompassed it from all sides. A chest CT scan revealed multiple metastatic lesions in the lungs (approximately 25 metastases in total).
Results. The patient underwent emergency surgery, including a laminectomy from the 2nd to 4th cervical vertebrae with partial resection of the extradural soft tissue component of the tumor. Postoperatively, almost complete regression of neurological deficits was noted, with a score of 4.5 in the legs and 4.5 in the arms, as well as regression of pelvic abnormalities. The patient was transferred to the Pediatric Oncology Department of the Dmitry Rogachev National Medical Research Center for Pediatric Hematology, Oncology, and Immunology, where multimodal chemotherapy and radiation therapy were initiated.
Conclusion. Primary Ewing sarcomas affecting the C2 vertebra are extremely rare. This location presents diagnostic challenges due to its atypical clinical presentation and radiographic and histopathological similarities to other tumors. This case highlights the importance of a multidisciplinary approach for accurate diagnosis and optimal treatment. More accurate recognition of these rare forms can facilitate early diagnosis and improve patient prognosis.
Contribution: Rynda A.Yu., Vorozhtsov I.N., Grachev N.S., Sanakoeva A.V., Tarakanova A.V. — study concept and design; Rynda A.Yu., Papusha L.I., Vorozhtsov I.N., Sanakoeva A.V., Tarakanova A.V., Tereshchenko G.V. — data collection and processing, statistical processing; Rynda A.Yu., Karachunsky A.I., Sanakoeva A.V., Tarakanova A.V., Tereshchenko G.V. — writing the text; Rynda A.Yu., Papusha L.I., Grachev N.S., Lopatin A.V., Karachunsky A.I. — scientific editing. All co-authors approved the final version of the article and are responsible for the integrity of all parts of the article.
Acknowledgments. The study had no sponsorship.
Conflict of interest. The authors declare no conflict of interest.

Received: January 19, 2026
Accepted: February 10, 2026
Published: February 27, 2026

Hyperphosphatasia with mental retardation represents an extremely rare group of autosomal recessive metabolic disorders of glycosylation caused by glycosylphosphatidylinositol biosynthesis defect. Hyperphosphatasia is characterized by psychomotor development delay, seizures, variable congenital malformations, and a typical phenotype. A distinctive feature is a consistently elevated serum alkaline phosphatase level. We present a case of an 8-month-old boy with psychomotor retardation and multiple congenital malformations: Hirschsprung’s disease, bilateral obstructive megaureter with ureteral ectopia, and cryptorchidism. Diffuse muscular hypotonia, brachytelephalangy, and a characteristic facial phenotype were noted on examination. The maximum increase in the level of alkaline phosphatase was 1900 U/l. The differential diagnosis was carried out with microdeletion syndromes and Mowat‒Wilson syndrome. According to the results of whole exome sequencing with segregation analysis of the PIGV gene (NM_017837.4), the previously described pathogenic variant c.1022C>A (p.Ala341Glu) and the previously undescribed variant c.103_110del (p.Asp35Cysfs*32) were identified in the trans-configuration. Hyperphosphatasia with mental retardation, type 1, was diagnosed. The data obtained allows to expand knowledge about the phenotypic spectrum and differential diagnosis of hyperphosphatasia, which helps to verify the diagnosis and prevent birth of affected children.
Contribution: Kondakova O.B., Savostyanov K.V., Dyakonova E.Yu. — study concept definition of treatment tactics, manuscript editing; Gudkova A.P., Grebenkin D.I., Demyanov S.V., Davydova Yu.I., Tarzyan A.O., Pushkov A.A. — collection and processing, treatment manuscript writing. All co-authors approved the final version of the article and are responsible for the integrity of all parts of the article.
Acknowledgments. The study had no sponsorship.
Conflict of interest. The authors declare no conflict of interest.

Received: December 10, 2025
Accepted: March 20, 2026
Published: March 27, 2026