General Characteristics of Autoimmune Encephalitis (AE) in Children:

• AE is a group of heterogeneous, non-infectious, immune-mediated inflammatory diseases of the CNS.
• Key characteristic: diverse neuropsychiatric symptoms associated with antibodies against neuronal and glial proteins, receptors, and ion channels.

Epidemiology and Relevance of the Problem:

• According to recent data, the prevalence of AE may reach up to 13.7 cases per 100,000 population, which is comparable to the incidence of infectious encephalitis.
• In recent years, there has been an increase in AE detection rates, linked to the discovery of new antibodies and advancements in diagnostic methods.

Main Diagnostic Challenges in Pediatrics:

• Lack of approved clinical guidelines for AE specifically tailored to the pediatric age group.
• A significant proportion of patients (up to 60%) show no abnormalities on brain MRI.
• Seronegative forms exist (up to 40% of cases), where specific antibodies are not detected in serum and Cerebrospinal Fluid (CSF).

Diagnostic Approach (Illustrated by a Case of Autoimmune Psychosis):

• The diagnostic algorithm for acute psychotic disorders (onset within less than 3 months) includes:
• Neuroimaging (brain MRI).
• Electroencephalography (EEG).
• CSF examination (clinical analysis, search for oligoclonal bands, infectious markers).
• Blood test for antineuronal antibodies.
• Cancer screening to rule out a paraneoplastic origin of encephalitis.

The Key Role of Laboratory Diagnostics:

• Detection of specific antineuronal antibodies (in serum and/or CSF) is central to confirming the diagnosis and defining the specific type of AE.
• In the clinical example, a 9-year-old girl was found to have a positive anti-MOG status.

Clinical Case: A 9-year-old Girl with Anti-MOG Encephalitis:

• History: Acute onset with seizure activity and cognitive decline. A brain tumor (protoplasmic astrocytoma) was initially suspected and operated on, but histological re-evaluation did not confirm it. There was no response to radiation therapy.
• Neurological Status: Cognitive deficit (short-term memory loss), psycho-emotional agitation, echolalia, mild right-sided pyramidal signs.
• Key Findings: Video-EEG Monitoring (VEEGM) showed slowing in the left parieto-central region. CSF analysis revealed antibodies to MOG (myelin oligodendrocyte glycoprotein).
• Treatment and Outcome: Pulse therapy with methylprednisolone was initiated. Follow-up MRI showed positive dynamics after treatment.

Modern Trends in Treatment and Scientific Prospects:

• The cornerstone of acute therapy consists of immunosuppressive drugs (corticosteroids, intravenous immunoglobulins - IVIg, plasmapheresis).
• Groundbreaking scientific work (Nobel Prize 2025) studying the role of regulatory T-cells in immune response control has been noted. These discoveries pave the way for the development of more targeted and safer therapies for autoimmune diseases, including AE.

Conclusion:

Despite progress in diagnostics (discovery of new antibodies), establishing a reliable diagnosis of AE in children remains a challenging task. This is due to the lack of pediatric-specific guidelines, the frequent absence of MRI changes, and the high proportion of seronegative forms.

TBA