Opsoclonus-myoclonus syndrome (Kinsbourne encephalopathy) is a rare neurological disorder characterized by combination of abnormal eye movements (opsoclonus), myoclonus, and cerebellar ataxia. Opsoclonus-myoclonus syndrome develops primarily in children due to immune system pathology associated with infectious or oncological diseases. If this syndrome is comorbid to neuroblastoma, timely diagnosis and complex management determine prognosis for patient’s life and nervous system functions recovery. The variety of factors triggering immunopathological process determines the need for differential diagnosis with wide range of diseases and raising medical community awareness about this rare syndrome. Therapeutic approaches have been being improved due to clinical data accumulation, long-term consequences analysis, and study of pathogenesis. Interaction and succession between neurologists, pediatricians, oncologists, as well as oncological alertness on all stages of patient management are crucial for diagnosis and choosing treatment tactics.

Pancreatitis refers to digestive system diseases that are challenging to diagnose and manage. They are also associated with irreversible changes in the organ’s parenchyma, that can lead to lethal outcome. The etiology of pancreatitis is diverse due to various exogenous and endogenous factors that determine the nature and severity of the pathological process itself. The major causes in children are the following: obstruction of ductus choledochus or duodenal papilla, abdominal trauma, viral infections, and some medications. Experts have revealed, after several studies, the association between pancreatitis and genetic factors causing up ton 75% of cases of chronic pancreatitis. Nowadays, genes associated with hereditary pancreatitis include PRSS1 (cationic trypsinogen gene), SPINK1 (serine peptidase inhibitor Kazal, type 1), CFTR (cystic fibrosis transmembrane conduction regulator), CTRC (encoding the functions of chymotrypsin C). The diagnostic criteria for hereditary pancreatitis have been established as for any other pancreatitis. The leading method for visualization of changes in pancreas remains ultrasound (US) examination of abdominal organs, endoscopic US, or magnetic resonance imaging. Molecular genetic testing is advisable for children with manifestations of pancreatitis in addition to recommended basic examinations.

Background. Long QT syndrome is hereditary disease, cardiac canalopathy variant, characterized by syncope and high risk of sudden cardiac death due to occurrence of polymorphic ventricular tachycardia (VT), torsade de pointes, and ventricular fibrillation. Acute respiratory viral infection may aggravate clinical course of primary electrical heart diseases.

Clinical case description. 14-year-old female patient was transferred to infectious diseases hospital from another hospital with positive PCR test on new coronavirus infection (COVID-19) after loss of consciousness in November 2021. Syncope was first noted at the age of 12, however then did not recur, and their examination and treatment were postponed due to the COVID-19 pandemic. Syncopal states continued during COVID-19. Cardiac examination was performed at infectious diseases hospital: recurrent VT, torsade de pointes, was diagnosed along with QT interval prolongation. The girl's condition has improved after the treatment and selection of antiarrhythmic therapy. 15 days later negative PCR test for SARS-CoV-2 was received, and the patient was transferred to specialized hospital, where the long QT syndrome was confirmed, and dual-chamber cardioverter defibrillator was installed.

Conclusion. This clinical case demonstrates that ARVI can aggravate the course of existing primary arrhythmia and emphasizes the crucial role of timely diagnosis and integrated approach to the management of patients with genetically determined cardiac arrhythmias.

Background. Kawasaki disease is an acute febrile systemic vasculitis occurring primarily in children under the age of five years old. It is characterized by high risk of cardiovascular complications development, including coronary vessels aneurysm. Its timely diagnosis is difficult in the absence of major clinical signs.

Clinical case description. 2-month-old child developed a disease with the signs of respiratory infection, exanthema syndrome, severe anemia, thrombocytosis; he has laboratory signs of inflammation (leukocytosis, neutrophil shift, increased erythrocyte sedimentation rate and C-reactive protein level). The detection of early antibodies to cytomegalovirus infection and tick-borne borreliosis causative agent indicated the infectious nature of the disease. Clinical diagnosis was established: “Mixed infection: Lyme borreliosis, non-erythematous form, and unspecified serous meningitis, moderate severity, non-mild course. Prior disease complication: toxic-allergic dermatitis, secondary cardiopathy (toxic-infectious origin). Comorbid conditions: acquired cytomegalovirus infection, generalized form, with involvement of respiratory tract (nasopharyngotonsillitis), skin (exanthema syndrome), and hemopoietic system (severe anemia)”. The patient was transferred from somatic to infectious department, where he was administered with several courses of antibiotic therapy (ceftriaxone, cefepime, meropenem, vancomycin), antiviral drugs (viferon suppositories, acyclovir), RBC-transfusion was performed due to severe anemia. Single administration of human immunoglobulin was performed on the 18th day of the disease. The child was discharged with clinical recovery on the 35th day from the disease onset. Coronary artery aneurysm was revealed on the 30th day after discharge, retrospective diagnosis was established: Kawasaki disease.

Conclusion. Prolonged fever with nonspecific clinical manifestations of Kawasaki disease resulted in its late diagnosis. The disease was revealed only after the development of typical and at the same time severe complication — coronary artery aneurysm. Pediatricians should keep awareness on cases with long-term signs of inflammation with no established infectious disease.

Background. Niemann – Pick disease (NPD) is a rare autosomal recessive disease caused by acid sphingomyelinase deficiency and characterized by impaired intracellular lipids’ transport leading to accumulation of cholesterol and glycosphingolipids in the cells. Olipudase alfa was registered as the drug for enzyme replacement therapy in 2022. There are only two studies and one observation published on the results of its implementation in children. Olipudase alfa efficacy and safety have not been studied in Russian studies.

Clinical case description. Girl, 1 year 5 months old, was diagnosed with insufficient weight gain and dyspeptic syndrome. Subsequently the child was followed up with various gastroenterological diagnoses for 1.5 years. Diagnosis of NPD type B was established at the age of 3 years 4 months, it was confirmed by revealing acid sphingomyelinase activity decrease to 0.11 mmol/l/h and nucleotide variant in the SMPD1 gene. Therapy with olipudase alfa was initiated at the age of 3 years 10 months with increasing dosage (from 0.03 mg/kg to therapeutic — 3 mg/kg of body weight, 11 injections in total), intravenously, drop infusion, once in 2 weeks. Clinical progression of the disease has stopped (with persistent hepatosplenomegaly), positive changes in laboratory parameters of the disease activity were revealed (with persistence of high (66 U/L) aspartate aminotransferase activity), and increasing of body weight (however, physical development remains below average, –1 to –2 SD) was noted within 24 weeks of therapy.

Conclusion. The combination of hepatosplenomegaly, increased transaminase activity and cholesterol levels, gastroenterological symptoms, and insufficient body weight gain should rise doctors’ awareness of orphan disease in a child. Timely diagnosis of NPD is crucial for early enzyme replacement therapy initiation (that is currently available). We have shown that olipudase alfa can help us to maintain child’s vital activity, to achieve positive clinical and laboratory dynamics, and to reach slow recovery of the child’s physical development.

Background. Gingival hyperplasia is a pathological diffuse or local outgrowth of fibrous tissue in the gums and paradontium. Excessive growth of gum tissue can cause periodontal inflammation and results in tooth loss, speech and chewing issues, aesthetic changes. The described cases of gingival hyperplasia in children on cyclosporine therapy are limited by the short follow-up (up to 2 months) and do not contain data on cyclosporine levels in the blood and hyperplasia regression after treatment cessation.

Clinical case description. The child, 8 years 10 months old, male, was hospitalized for nephrotic syndrome management. He was consulted by the dentist several times due to gingival hyperplasia; topical therapy had no effect. Therapy of nephrotic syndrome was revised during hospital stay. Two drugs were identified that could provoke the hyperplasia development: cyclosporine (on-treatment period — 5 years 10 months) and amlodipine (on-treatment period — 1 year 6 months). Monitoring of ciclosporin levels in blood was prescribed. Episodes of increased cyclosporine levels (above the recommended values) were recorded. The drug was considered as the most likely cause of drug-induced gingival hyperplasia. Amlodipine was considered as additive factor exacerbating the side effect. Both drugs were discontinued. Gingival hyperplasia regression was noted 9 months later at return to the clinic.

Conclusion. Administration of drugs associated with high risk of gingival hyperplasia development requires dynamic follow-up for timely therapy correction and severe complications prevention.

However, monitoring of ciclosporin levels does not guarantee the prevention of side effects.