Neuronal surface antibodies are common in children with narcolepsy and active movement disorders

Clinical characteristics of Leucine-rich glioma-inactivated protein 1 antibody-mediated autoimmune encephalitis in a 6-year-old girl: case report and literature reviews

BACKGROUND

Autoimmune encephalitis related to the leucine-rich glioma-inactivated protein 1(LGI1) antibody is the most prevalent in older adults, manifesting as seizures, faciobrachial dystonic seizures (FBDS), cognitive impairment, memory disturbance, hyponatremia and neuropsychiatric disorders. However the data pertaining to children affected by the disease is still limited.

CASE PRESENTATION AND LITERATURE REVIEWS

This study presents a detailed report of a 6-year-old Chinese girl who experienced nose aches and faciobrachial dystonic seizures (FBDS). Electrolyte testing revealed that she had hyponatremia and brain MRI showed an abnormality in the left temporal pole. Additionally, anti-LGI1 antibodies were detected in both her serum (1:100) and CSF (1:30). The patient was treated with immunotherapy and symptom management, which proved effective. Furthermore, we provide a summary of 25 pediatric cases of anti-LGI1 encephalitis. Pediatric patients rarely exhibited FBDS and hyponatremia, and some cases presented with isolated syndromes. But the therapeutic outcomes of pediatric patients were generally good.

CONCLUSIONS

In this report, we describe a patient who developed a rare symptom of nose aches possibly as one of symptoms of anti-LGI1 encephalitis, which highlights the possibility of atypical symptoms in children that may be misdiagnosed. Reviewing the literature, the clinical features differed between pediatric and adult cases. Therefore, it is crucial to collect and analyze data from more cases to promote accurate diagnosis and timely treatment.

Reviewing the Clinical Implications of Treating Narcolepsy as an Autoimmune Disorder

Narcolepsy type 1 (NT1) is a lifelong sleep disorder, primarily characterized clinically by excessive daytime sleepiness and cataplexy and pathologically by the loss of hypocretinergic neurons in the lateral hypothalamus. Despite being a rare disorder, the NT1-related burden for patients and society is relevant due to the early onset and chronic nature of this condition. Although the etiology of narcolepsy is still unknown, mounting evidence supports a central role of autoimmunity. To date, no cure is available for this disorder and current treatment is symptomatic. Based on the hypothesis of the autoimmune etiology of this disease, immunotherapy could possibly represent a valid therapeutic option. However, contrasting and limited results have been provided so far. This review discusses the evidence supporting the use of immunotherapy in narcolepsy, the outcomes obtained so far, current issues and future directions.