Clinical and etiological features of encephalitis in young and elderly children
The purpose of the work is to study the etiological factors and clinical features of the course and outcomes of encephalitis in children. Material and methods. An analysis of the etiology, clinical picture, course and outcome of encephalitis (EF) was carried out in 364 children aged 1 month to 17 years. Results. The frequency of EF in children of the first three years of life was 34% (n = 124), and among children from 4 to 17 years old the largest number of cases was at the age of 4-6 years (21.2%, n = 77). In children under 3 years of age, EFs were more often caused by cytomegalovirus (21.8%) and enterovirus infections (13.2%), herpes simplex virus (HSV) type 2 was found ~ 2.6 times more often than HSV-1. In the group of children under 3 years of age, congenital infection was the cause of EF in 47.5% of cases, and in 43.2% of cases their development was observed during seasonal epidemic rises. In the etiology of EF in children from 4 to 17 years, varicella-zoster virus (VZV) (16.7%), tick-borne infections, which put together 21.2%, as well as Epstein-Barr virus (11.7%) and enteroviruses (11, 7%). In children of the older group, 73.3% of cases of EF developed sporadically and in 94.2% with acquired infections. In young children, extrapyramidal, speech disorders, and epileptic seizures were significantly more common, and great severity of pyramidal symptoms was noted. At the age of 1 month up to 3 years in 84.7% of cases, isolated damage to brain structures was observed, in most cases against the background of fever, genitalized exanthema, inflammation of the upper respiratory tract, and in 22.5% of the internal organs. Whereas in children older than 4 years, in 41.2% of cases simultaneously with the brain was involved the spinal cord and/or cranial and/or spinal nerves, and EF symptoms in 68.7% developed at a low-grade or normal temperature with a significantly lower frequency of extracerebral symptoms. The acute or peracute course of EF in children under 3 years of age was in 72.6% of cases, was accompanied by the development of complications in 69.4% of cases, the main of which was cerebral edema. In patients older than 4 years, protracted and chronic course occurred in more than <sup>1</sup>A of cases (52.1%), and complications were observed in ~ 1/3 of children. Young children had ~ 2.5 times greater mortality (3.2% and 1.3%, respectively), as well as the frequency of motor and cognitive deficits and symptomatic epilepsy. With the development of EF in the older group with lesions of the white matter and optic-encephalomyelitis syndrome, in 6% of cases exacerbation led to the development of multiple sclerosis.