Clinical seizure features and EEG pattern in patients with anti-leucine-rich glioma-inactivated 1 antibody-associated encephalitis

Abstract

Objective To summarize clinical seizures and electroencephalography (EEG) characteristics of patients with anti ? leucine ? rich glioma ? inactivated 1 (LGI1) antibody ? associated encephalitis. Methods Clinical manifestations, imaging and EEG characteristics, treatment and prognosis of 35 patients with anti?LGI1 antibody?associated encephalitis, who were clearly diagnosed by laboratory examinations and followed up for 2 years, were analyzed. Results Thirty?five patients included 26 males and 9 females, median age 57.35 years. Of all 35 cases, 31 cases (88.57%) had epileptic seizures, mainly as complex partial seizure (CPS), and 13 cases (37.14%) had faciobrachial dystonic seizures (FBDS). Brain MRI showed T2WI and FLAIR high?intensity signals in bilateral (16 cases) or unilateral (12 cases) mesial temporal lobes. 18F ? fluoro ? 2 ? deoxy ? D ? glucose (18F ? FDG) PET examination showed hypermetabolism in temporal lobe and/or basal ganglia (22/24). Thirty?one patients performed video EEG (VEEG) examination, among whom 23 patients showed abnormal background activity, manifesting as diffuse slow waves or regional slow waves in frontotemporal region; 18 cases showed anterior temporal epileptic discharges. There were 22 cases grasping seizures in VEEG, among whom 18 cases obtained epileptic seizures and 13 of them were temporal lobe onset CPS (10 cases) or simple partial seizure (SPS, 7 cases) including pilo?erection seizure in 5 cases, myoclonic seizure in 4 cases and secondary generalized tonic?clonic seizure (GTCS) in one case. Two of 6 FBDS patients showed epileptic discharges followed by temporal lobe onset. Twenty?seven cases received oral antiepileptic drugs (AEDs), among whom 4 of 25 patients with epileptic seizures had reduced frequency ≥ 50%, while 11 FBDS patients had no effect, 8 cases (29.63%) had anaphylaxis. Thirty?five patients received immunomodulation treatment, including intravenous immunoglobulin (IVIg) in 33 cases, corticosteroids in 33 cases, mycophenolate in 4 cases and zathioprine in 2 cases, the seizure frequency of all patients reduced ≥ 50% after treatment. After hospital discharge, 17 patients stop taking AEDs within one year and 26 patients stop taking AEDs within 2 years. Of the patients who were followed up for 2 years, 29 cases achieved epileptic seizure free, only 2 patients developed to chronic epilepsy (anti?LGI1 antibody were negative while seizures were not free). Conclusions Anti?LGI1 antibody?associated encephalitis is a kind of autoimmune limbic encephalitis with specific clinical characteristics, often presenting with FBDS and temporal lobe seizures (typically with pilo?erection aura) combined with amnesia, psychiatric disorder/abnormal behavior and hyponatremia. Early diagnosis and timely immunotherapy can achieve good prognosis. DOI: 10.3969/j.issn.1672-6731.2018.05.006

Keywords

• Limbic encephalitis
• Tumor suppressor proteins
• Epilepsy
• Immunotherapy
• Electroencephalography