A Rare Case of GABAA Receptor Autoimmune Encephalitis in a Six-Year-Old Girl Improved by an Early Combined Immunotherapy

Introduction

Autoimmune encephalitis (AE) is an increasingly diagnosed disease entity of autoimmune inflammatory origin affecting the central nervous system. The incidence is approximately 1.5 to 2 cases per one million children (De Bruijn et al., Neurol Neuroimmunol Neuroinflamm 2020; 7(3): e682. doi: 10.1212/NXI.0000000000000682). Differentiating between normal infantile behavior and pathological symptoms is complicated by young childrenʼs limited capacity to accurately describe symptoms. Further complexity arises due to the overlap of clinical symptoms across inflammatory, infectious, metabolic and psychiatric diseases, posing challenges to the diagnostic process (Cellucci et al., Neurol Neuroimmunol Neuroinflamm 2020; 7(2): e663. doi:10.1212/NXI.0000000000000663). In particular, it can be challenging to distinguish between viral and bacterial meningoencephalitis, acute disseminated encephalomyelitis, and AE during the early stages of the disease.The possible occurrence of a paediatric autoimmune encephalitis (AE) must be considered if the criteria established by Cellucci and colleagues are met ([Fig. 1]) (Cellucci et al., Neurol Neuroimmunol Neuroinflamm 2020; 7(2): e663. doi:10.1212/NXI.0000000000000663). An AE can be confirmed by detecting the neuronal surface antibodies present in the cerebrospinal fluid (CSF) or serum.

Nevertheless, this confirmation is not compulsory because frequently no autoantibodies are found in children with suspected or probable AE (Cellucci et al., Neurol Neuroimmunol Neuroinflamm 2020; 7(2): e663. doi:10.1212/NXI.0000000000000663). Since the 1980s, more than 25 different antibodies have been associated with AE (Bien & Bien, Neurol Res Pract 2020; 267: 2101–2114). The most common antibodies detected in children and adolescents are the ones that target the myelin oligodendrocyte glycoprotein (MOG) and the anti-N-methyl-D-aspartate receptor (NMDA receptor) (Bien & Bien, Neurol Res Pract 2020; 267: 2101–2114). AE-associated antibodies, which are infrequently found, target the dopamine-2 receptor, glutamic acid decarboxylase-65 (GAD65), glycine receptor, γ-amino-butyric acid receptor type A (GABA_A receptor)/type B (GABA_B receptor) as well as contactin-associated-protein-like 2 (CASPR2) and leucine-rich-glioma-inactivated-protein 1 (LGI1). Often, clinical and radiological findings already give clues for a specific antibody (Cellucci et al., Neurol Neuroimmunol Neuroinflamm 2020; 7(2): e663. doi:10.1212/NXI.0000000000000663). In the following case report, we describe a patient with a GABA_A receptor AE who presented with new-onset of headache, paraesthesia, focal seizures and psychiatric symptoms.

Publication History

Article published online:
06 August 2024