RESUMO
BACKGROUND: Anti-leucine-rich glioma inactivated protein 1 (anti-LGI1) encephalitis is an infrequent type of autoimmune encephalitis (AE) characterized by acute or subacute cognitive and psychiatric disturbance, facio-brachial dystonic seizures (FBDSs), and hyponatremia. Anti-LGI1 AE has increasingly been considered a primary form of AE. Early identification and treatment of this disease are clearly very important. CASE SUMMARY: Here, we report that a male patient developed severe anti-LGI1 encephalitis, which was initially misdiagnosed as a sleep disturbance. He was hospitalized for epileptic seizures and typical FBDSs half a month after he developed sleep disturbances. LGI1 antibodies were detected in his cerebrospinal fluid and serum (1:100 and 1:3.2, respectively), which led to the diagnosis of classic anti-LGI1 AE. No obvious abnormality was observed on brain computed tomography images. T2-weighted fluid-attenuated inversion recovery and T2-weighted scans of brain magnetic resonance imaging (MRI) showed slightly elevated signals within the left basal ganglia area. No tumor was detected within the brain of this patient using MRI. After hormone and antiepileptic drug treatment, the patient's symptoms improved significantly. CONCLUSION: Anti-LGI1 antibody-associated encephalitis has characteristic clinical manifestations, such as cognitive impairment, psychiatric symptoms, seizures, sleep disorders, hyponatremia, and FBDSs. LGI1 antibodies are present in the serum and/or cerebrospinal fluid, but their production is sensitive to immunosuppressants, and this disease has a relatively good prognosis. In particular, we should be aware of the possibility of anti-LGI1 antibody-associated encephalitis in adolescents with sleep disorders to avoid missed diagnoses and misdiagnoses.
