The microbiota plays a key role in the physiology and maintenance of homeostasis in the child’s body. It is important to know the processes of formation of the intestinal microbiota that begin in utero. The baby continues to receive the mother’s microflora during childbirth and breastfeeding. The results of molecular genetic studies indicate that the most intensive process of microbial colonization of a child is associated with dietary habits. The main factor in maintaining the stability and resistance of normobiota is microbial autometabolites. The most promising areas of probiotic biotechnology and the development of metabolic probiotics (metabiotics), probiotics in combination with prebiotics (synbiotics) are considered. Understanding the processes of formation of intestinal microflora allows developing effective methods for the prevention and correction of microecological and motor disorders of the gastrointestinal tract in the age aspect.

Relevance: Hirschsprung’s disease (HD) is a congenital disease characterized by the absence of ganglion cells in the submucosal nerve plexus of Meissner, as well as the muscular-intestinal nerve plexus of Auerbach. This disease is one of the variants of neurocrystopathies and leads to disorders of intestinal peristalsis, which most often manifest themselves in the form of colon obstruction. About 80% of cases are caused by genetic mutations that are autosomal dominant with incomplete penetrance. The first symptoms of the disease usually appear immediately after birth, with a difficult discharge of meconium, in the future the disease is masked under chronic constipation, with which such patients most often come to see pediatricians. Aim: to present a clinical case of Hirschsprung’s disease, under the guise of chronic constipation Material and methods: The medical history of a boy aged 3 years 9 months with Hirschsprung’s disease, rectosigmoid form, subcompensation stage is presented.

The article presents an analysis of the work of the largest children's COVID-19 center in Moscow, organized on the basis of the Children's City Clinical Hospital named after Z. A. Bashlyaeva of the Moscow City Health Department. From March to November 2020 at the COVID-19 Center were hospitalized 2,837 patients with suspected/confirmed diagnosis of COVID-19, in total in 2020 1,876 children with a confirmed diagnosis of COVID-19 were treated, 58 (3%) children were in serious condition in the intensive care unit, of which children 11-18 years old were 25%. At the 2020 neonatal COVID-19 center, 215 newborns were observed with suspected COVID-19 diagnosis. The diagnosis of COVID-19 was confirmed in 18 children, while 8 newborns came from the home of COVID-19. In the Center for rehabilitation, where children aged 0 to 3 years old who were born with very low and extremely low body weight are observed, dispensary observation for children who have undergone COVID-19 is organized. 45 children who were observed fell ill with the new coronavirus infection. There were no deaths among children with COVID-19.

Relevance: Hereditary connective tissue disorders (HCTDs) are a heterogeneous group of diseases caused by mutations in the genes of extracellular matrix proteins or proteins involved in connective tissue morphogenesis. Mutations of these genes lead to the development of many HCTDs. The best known monogenic variants of HCTDs are Marfan syndrome, Ehlers-Danlos syndrome, and osteogenesis imperfecta. Inheritance is mainly autosomal, dominant or recessive. Although the first signs of HCTDs develop as early as the first year of life, it takes several years for pediatricians and specialty physicians to make the diagnosis of connective tissue dysplasia because of a lack of clear methodological approach. The disease is multi-morbid and may manifest under gastroenterological, cardiological, nephrological, or respiratory masks.Aim: to present a clinical case of Ehlers-Danlos syndrome with multiorgan digestive, heart, kidneys, and other lesions.Material and methods: the case history is presented of a 15‑year-old boy with Ehlers-Danlos syndrome, classic type.Discussion: defective collagen increased the connective tissue extensibility affecting function of many body organs and systems, including gastrointestinal, biliary, and urinary tracts, musculoskeletal and cardiovascular systems. Small developmental anomalies led to functional (motor) disorders, which contributed to the chronic organic pathology (erosive reflux esophagitis, gastroduodenitis, cholelithiasis, proctosigmoiditis, chronic pyelonephritis, or chronic sinusitis). Given the multi-organ character of the lesions, the progredient course of bone and joint changes, and early development of disability, the prognosis for the health of this child is serious. A multidisciplinary approach is important to plan the follow-up (with orthopedist, gastroenterologist, cardiologist, ophthalmologist, and nephrologist). Timely rehabilitation, therapeutic physical training courses, massage, metabolic, and anti-relapse treatment are necessary to slow down the progredient course of the hereditary connective tissue disease.

Objective of the Paper: To represent a case of the novel coronavirus infection COVID-19 in a 4-year-old child with isolated bowel damage. Key Points. COVID-19 impacts several systems and organs. Usually, children have mild or asymptomatic disease. Clinical manifestations of COVID-19 in children can be damage not only of respiratory tract, but also of GIT, requiring differential diagnosis of enteric infections (both viral and bacterial). Prompt diagnosis of COVID-19 is essential for antiepidemic measures and suppression an infectious process. The case shows challenges faced by clinicians when diagnosing COVID-19 in patients with isolated GIT damages without catarrhal signs. Course of the disease in this patient was characterised by a number of features indicative of a bacterial enteric infection: abdominal pain, diarrhoea, increased CRP, colitis syndrome in stool test, warranting differential diagnosis of acute enteric bacterial infections. Negative bacterial culture, detection of SARS-CoV2 RNA in oropharynx and nasopharynx mucous, fast stool normalisation and dyspeptic events arrest allowed diagnosing that the diarrhoea was associated with COVID-19. One month of metabolic and probiotic therapy normalised stool, arrested abdominal pain, and improved exercise tolerance. Conclusion. GIT damage in paediatric COVID-19 patients is essential and unexplored. COVID-19 should be added to differential diagnosis in case of clinical manifestations of an acute enteric infection. Keywords: children, novel coronavirus infection, COVID-19, GIT.

Rationale. In recent decades, the number of children has increased with chronic diseases characterized by systemic lesions and frequent involvement of the digestive tract, complicating the diagnosis and choice of therapeutic strategy. As the number of diseases in a child increases, the cost of diagnosis and treatment grows exponentially. Given the comorbidity, physicians prescribe multiple medications (polypragmasy), which can lead to adverse effects.First-line physicians often lack the knowledge about the clinical and therapeutic features of managing comorbid patients. Practical healthcare lacks a “team strategy” for these patients’ treatment, leading to ineffective management of patients by subspecialist physicians significantly affecting the prognosis of the disease and even the life of the patient. The “narrowly specialized” model of medicine is inadequate. An integrative model of healthcare should replace it. Meanwhile, there are currently no international and national recommendations for this problem focused on the needs of “first line” physicians, including pediatric specialists. All the above urged us to provide an in-depth study of this problem in the current literature.The aim of this literature review was to study the frequency and structure of comorbid conditions in pediatric practice to optimize their diagnostics, therapeutic tactics, and the development of preventive measures.Results and discussion. The structure of comorbidity differs in different age categories. The comorbidity in children depends mainly on the genetically programmed disorders of metabolism and functioning of cells and tissues, disorders of nutritional status, infectious factors, and interference (pathogenetic relationship of diseases). Understanding the etiology and pathogenesis of comorbid conditions in children, one should identify the Chronic Noncommunicable Diseases formation risk groups and develop a plan for their prevention. Prevention of comorbid chronic noncommunicable diseases should be carried out as part of the “full life cycle”, from the antenatal period (the health of the future mother) to adolescence, using an integrative approach (impact on the child’s physical and mental condition) with teaching patients and their parents the basics of proper diet, healthy lifestyle, sufficient physical activity, and positive attitude.Knowledge of causal and complicated comorbidity will contribute to the development of optimal diagnostic tactics for the search of the root cause and the selection of efficient therapy for trigger disease, which will avoid polypragmasy. The pediatric physician should play the primary role in the follow-up of comorbid patients. It is necessary to expand the competencies of the pediatric physician with the revision of approaches to his professional training.The development of clinical guidelines and algorithms for the management of comorbid patients and the collaboration of physicians of various specialties (formation of multidisciplinary teams), while observing the principle of “one doctor”, will significantly improve the quality of medical care for comorbid patients, which will improve their quality of life and significantly decrease the cost of rehabilitation measures.

Rationale. In recent decades, the number of children has increased with chronic diseases characterized by systemic lesions and frequent involvement of the digestive tract, complicating the diagnosis and choice of therapeutic strategy. As the number of diseases in a child increases, the cost of diagnosis and treatment grows exponentially. Given the comorbidity, physicians prescribe multiple medications (polypragmasy), which can lead to adverse effects. First-line physicians often lack the knowledge about the clinical and therapeutic features of managing comorbid patients. Practical healthcare lacks a “team strategy” for these patients’ treatment, leading to ineffective management of patients by subspecialist physicians significantly affecting the prognosis of the disease and even the life of the patient. The “narrowly specialized” model of medicine is inadequate. An integrative model of healthcare should replace it. Meanwhile, there are currently no international and national recommendations for this problem focused on the needs of “first line” physicians, including pediatric specialists. All the above urged us to provide an in-depth study of this problem in the current literature. The aim of this literature review was to study the frequency and structure of comorbid conditions in pediatric practice to optimize their diagnostics, therapeutic tactics, and the development of preventive measures. Results and discussion. The structure of comorbidity differs in different age categories. The comorbidity in children depends mainly on the genetically programmed disorders of metabolism and functioning of cells and tissues, disorders of nutritional status, infectious factors, and interference (pathogenetic relationship of diseases). Understanding the etiology and pathogenesis of comorbid conditions in children, one should identify the Chronic Noncommunicable Diseases formation risk groups and develop a plan for their prevention. Prevention of comorbid chronic noncommunicable diseases should be carried out as part of the “full life cycle”, from the antenatal period (the health of the future mother) to adolescence, using an integrative approach (impact on the child’s physical and mental condition) with teaching patients and their parents the basics of proper diet, healthy lifestyle, sufficient physical activity, and positive attitude. Knowledge of causal and complicated comorbidity will contribute to the development of optimal diagnostic tactics for the search of the root cause and the selection of efficient therapy for trigger disease, which will avoid polypragmasy. The pediatric physician should play the primary role in the follow-up of comorbid patients. It is necessary to expand the competencies of the pediatric physician with the revision of approaches to his professional training. The development of clinical guidelines and algorithms for the management of comorbid patients and the collaboration of physicians of various specialties (formation of multidisciplinary teams), while observing the principle of “one doctor”, will significantly improve the quality of medical care for comorbid patients, which will improve their quality of life and significantly decrease the cost of rehabilitation measures.

A case of the drug-induced liver injury (DILI) development is presented on the background of the self-treatment with an antiparasitic drug Albendazole in an 11 years-old girl with several risk factors for the drug-induced liver injury (history of a drug reaction, carbohydrate and fat metabolism disturbance, female gender, and adolescence). The disease was diagnosed using the the CIOMS/RUCAM scale. The drug was withdrawn and the pathogenetic therapy was established (fluids, hepatoprotective drugs) with the resolution of the drug-induced hepatitis.

Microbiota plays a key role in the physiology and maintenance of homeostasis of the human body. The importance belongs to the processes of the formation of the intestinal microbiota, starting in utero, and the child continues to receive the mother's microflora during childbirth and breastfeeding. The results of molecular genetic studies indicate that the most intensive process of microbial colonization in infant is associated with features of feeding. The main factor in maintaining the stability and resistance of normal biota is microbial autometabiolites. Considered the most promising probiotic biotechnology and development metabolic of probiotics (metabiotics) probiotics in combination with Prebiotics (synbiotics). Understanding the processes of formation of intestinal microflora allows you to develop effective methods of prevention and correction micro-ecological and motor disorders in the age aspect.

Drug-induced liver injury is a disease that occurs during the administration of medications, which is controlled or has a positive dynamics after the drug administration is discontinued, and the renewed prescription of which causes a relapse of clinical and laboratory signs of liver injury. No unified diagnostic criteria have been developed yet. We used the following diagnosis criteria: any excess of the levels of total bilirubin, direct bilirubin, transaminases; temporary association with administration of medications; ruling out other causes of liver injury.Results. 114 children with tuberculosis, aged 3 to 14, were examined. Drug-induced liver injury during the anti-TB therapy was diagnosed in 77 (67.5%) children. In almost half of the cases (37 children, 48%), the liver injury was asymptomatic and was diagnosed with a biochemical blood test. The most common clinical manifestation of pathology include dyspeptic syndrome (in 42.9% of children), less frequent one is abdominal pain syndrome (in 29.9%). The most common biochemical variant of drug-induced liver injury (in 64% of children) was a mixed variant (increased levels of transaminases and bilirubin). Also cytolytic syndrome was pronounced in 54% (in 31 of 57 children) of cases.Conclusions. Drug-induced liver injury during the administration of potentially hepatotoxic drugs should be actively detected by a control biochemical blood test every 2 weeks. Early detection of minimal clinical and laboratory symptoms of liver injury in patients with tuberculosis and timely initiation of treatment will allow controlling quickly liver injury, reducing the number of cases of cancellation of TB treatment, improving the outcome and prognosis for both tuberculosis and hepatic conditions.

Chloride diarrhea is a rare genetically determined disease caused by mutations of the SLC26A3 gene and characterized by the appearance of persistent watery diarrhea from the first days of the child’s life. The disease is accompanied by the development of hypokalemic hypochloraemic alkalosis. Features of the clinical aspects and metabolic disorders in congenital chloride diarrhea determine the need for differential diagnosis with a wide range of pathological conditions, which often leads to late diagnosis and increases the risk of complications. The article presents the clinical analysis of a patient with congenital chloride diarrhea, the criteria for diagnosing the disease, the possible errors in the diagnostic search process, describes the tactics of the child’s management.

Inflammatory bowel disease (IBD) is an immune-pathological disorder characterized by chronic progressive inflammatory destructive lesion of the gastrointestinal tract. The etiology of the IBD remains unknown. An example of clinical observation is presented to show the difficulty of differential diagnosis between Crohn’s disease and intestinal tuberculosis (TB) in a child with nodular pulmonary TB.

The article «Drug-induced liver injury in children with tuberculosis» describes data on the prevalence of drug-induced liver injury during TB therapy in children, recommendations for the diagnosis and the results of a randomized controlled trial of efficacy therapy with ursodeoxycholic acid of the drug-induced liver injury in children.

UNLABELLED:THE AIM OF THE RESEARCH: Improving the effectiveness of diagnostics and treatment of viral and drug-induced lesions of the liver (DILL) at a tuberculosis in children by identifying the frequency of their distribution, peculiarities of diagnostics and clinics.MATERIALS AND METHODS:We examined 242 children in the age from 2 months to 17 years, the patients with different forms of tuberculosis.RESULTS:The prevalence of hepatitis in children with tuberculosis: B - 1,2%, C-0.4%, G - 4,6%, TT - 8,7%. DILL was diagnosed in 67.5% of children - TB patients, in 48% of the children with DILL an asymptomatic course of the disease was noted, however, in 54.4% of the children with DILL cytolitic syndrome was expressed (ALT> standards).CONCLUSION:The prevalence of viral hepatitis B and C among children with TB is low. The infection with viruses of hepatitis G and TT is more often, but has no significant impact as on the course of tuberculosis, and on the severity of the liver damage. Drug-induced liver damage is a dominant view of pathology of the liver in children - TB patients and is mostly asymptomatic, but with a pronounced cytolitic syndrome.

The aim of the research: Improving the effectiveness of diagnostics and treatment of viral and drug-induced lesions of the liver (DILL) at a tuberculosis in children by identifying the frequency of their distribution, peculiarities of diagnostics and clinics. Materials and methods: We examined 242 children in the age from 2 months to 17 years, the patients with different forms of tuberculosis. Results: The prevalence of hepatitis in children with tuberculosis: B — 1,2%, C-0.4%, G — 4,6%, TT — 8,7%. DILL was diagnosed in 67.5% of children — TB patients, in 48% of the children with DILL an asymptomatic course of the disease was noted, however, in 54.4% of the children with DILL cytolitic syndrome was expressed (ALT> standards). Conclusion: The prevalence of viral hepatitis B and C among children with TB is low. The infection with viruses of hepatitis G and TT is more often, but has no significant impact as on the course of tuberculosis, and on the severity of the liver damage. Drug-induced liver damage is a dominant view of pathology of the liver in children — TB patients and is mostly asymptomatic, but with a pronounced cytolitic syndrome.