Pediatric bacterial purulent meningitis (BPM) and viral encephalitis (VE) are significant medical and social problems due to their course severity, high frequency of death cases, and formation of neurologic deficiency at the disease outcome. Activation of hormonal regulation and severity syndrome of systemic inflammatory response are important factors to evaluate the character of BPM and VE course.Objective.To study the level of cortisol and laboratory indicators of systemic inflammation in children with various variants of BPM and VE course depending on the period of the disease (acute period, reconvalescence) to specify their role in the pathogenesis of acute neuroinfections.Object and methods.There were investigated hematological indicators, the level of cortisol, C-reactive protein in blood serum of 60 children, 39 of them had BPM and 21 ones VE. The comparison group included 14 children aged from 1 to 14 years old who were undergoing rehabilitation care due to neurologic problems at the Federal State-Financed Institution Pediatric Research and Clinical Center for Infectious Diseasesunder the Federal Medical Biological Agency.Results.The patients were divided into some subgroups according to the severity of their condition at the moment of hospitalization, i.e. urgent condition or critical condition requiring organ replacement therapy. The maximum increase of cortisol level and laboratory markers of systemic inflammation during the acute period was revealed in case of BPM in comparison with VE with a subsequent normalization to the stage of reconvalescence. Thelevel of cortisol during the acute period of BPM was reliably higher in the subgroup with urgent conditions, whereas in case of VE in the subgroup with critical conditions. There were no significant differences in the laboratory indicators of systemic inflammation response among the subgroups. There was established a correlation interrelation of cortisol level and the content of granulocytes and blood lymphocytes.Conclusion.There were identified characteristic features of cortisol content in children with bacterial and viral neuroinfections depending on the course of the disease.

Disorders of control mechanisms caused by glucocorticoid hormones of adrenal cortex have a significant role in the pathogenesis of infectious diseases, first of all, due to cortisol, one of the key hormones with anti-inflammatory activity. Currently the conception about the mechanisms of cortisol influence, its functional abilities, connection with immune and nerve cells, involvement in cytokine regulation, features of free-radical oxidation has been extended. There has been identified the dependence of cortisol influence upon the isoform, amount and affinity of its receptors on target cells. The present review describes the study results concerning cortisol level in case of the most often occurring infectious diseases in children acute respiratory and intestinal infections, infectious diseases of the central nervous system. There has been noticed a considerable data variability about cortisol level in normal state and in pathological one, however, the majority of articles have detected its connection with clinical manifestations and outcomes of the diseases. The study of cortisol level in cerebrospinal fluid is of a special interest in case of neuroinfections, specifying its direct connection with the disease severity and aetiology that gives new possibilities to develop effective diagnostic criteria. In general, the literature data specifies the advanced study of disorders of hypothalamus-hypophysial-adrenal gland functioning, receptor apparatus of target cells, as well as interrelations of cortisol with immune system in case of infectious diseases to reveal new criteria for diagnostics, course prediction and disease outcome, therapy correction.