Pearls & Oy-sters: Limbic encephalitis associated with positive anti-LGI1 and antithyroid antibodies

Neuropsychological and Structural Neuroimaging Outcomes in LGI1-Limbic Encephalitis: A Case Study

OBJECTIVE

Anti-leucine-rich glioma-inactivated 1 limbic encephalitis (LGI1-LE) is a rare autoimmune condition that affects the structural integrity and functioning of the brain's limbic system. Little is known about its impact on long-term neuropsychological functioning and the structural integrity of the medial temporal lobe. Here we examined the long-term neuropsychological and neuroanatomical outcomes of a 68-year-old male who acquired LGI1-LE.

METHODS

Our case patient underwent standardized neuropsychological testing at two time points. Volumetric analyses of T1-weighted images were undertaken at four separate time points and qualitatively compared with a group of age-matched healthy controls.

RESULTS

At the time of initial assessment, our case study exhibited focal impairments in verbal and visual episodic memory and these impairments continued to persist after undergoing a course of immunotherapy. Furthermore, in reference to an age-matched healthy control group, over the course of 11 months, volumetric brain imaging analyses revealed that areas of the medial temporal lobe including specific hippocampal subfields (e.g., CA1 and dentate gyrus) underwent a subacute period of volumetric enlargement followed by a chronic period of volumetric reduction in the same regions.

CONCLUSIONS

In patients with persisting neurocognitive deficits, LGI1-LE may produce chronic volume loss in specific areas of the medial temporal lobe; however, this appears to follow a subacute period of volume enlargement possibly driven by neuro-inflammatory processes.

Clinical Features and Therapeutic Effects of Anti-leucine-rich Glioma Inactivated 1 Encephalitis: A Systematic Review

Background: Clinical presentations and treatment programs about anti-leucine-rich glioma inactivated 1 (LGI1) encephalitis still remain incompletely understood. Objective: This study analyzed the clinical features and therapeutic effects of anti-LGI1 encephalitis. Methods: PubMed, EMBASE, and the Cochrane Library were searched to identify published English and Chinese articles until April 2021. Data were extracted, analyzed, and recorded in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Results: A total of 80 publications detailing 485 subjects matched our inclusion criteria. Short-term memory loss (75.22%), faciobrachial dystonic seizures (FBDS) (52.53%), other seizures excluding FBDS (68.48%), psychiatric symptoms (57.67%), and sleep disturbances (34.30%) were the most frequently described symptoms in anti-LGI1 encephalitis. Hyponatremia (54.90%) was the most common hematologic examination change. The risk of incidence rate of malignant tumors was higher than in healthy people. The positive rate of anti-LGI1 in serum (99.79%) was higher than CSF (77.38%). Steroids (93.02%), IVIG (87.50%), and combined use (96.67%) all had a high remission rate in the initial visit. A total of 35 of 215 cases relapsed, of which 6/35 (17.14%) did not use first-line treatment, and 21 (60.00%) did not maintain long-term treatment. Plasma exchange (PE) could be combined in severe patients, immunosuppressant could be used for refractory patients or for recurrence and using an anti-epileptic drug to control seizures may benefit cognition. Conclusions: Short-term memory loss, FBDS, psychiatric symptoms, and hyponatremia were key features in identifying anti-LGI1 encephalitis. Serum and CSF antibody tests should be considered in diagnosis criteria. Steroids with IVIG should be recommended, PE was combined for use in severe patients, immunosuppressant therapy might improve outcomes if recurrence or progression occurred, and control seizures might benefit cognition. The useful ways to reduce relapse rate were early identification, clear diagnosis, rapid treatment, and maintaining long-term treatment. The follow-up advice was suggested according to the research of paraneoplastic syndrome, and concern about tumors was vital as well.

Case Report: Anti-LGI1 Limbic Encephalitis Associated With Anti-thyroid Autoantibodies

Anti-LGI1 encephalitis is an autoimmune encephalitis with antibodies against leucine-rich glioma-inactivated 1 (LGI1), first described in 2010. It is a non-frequent and poorly understood entity that represents the second most frequent cause of autoimmune encephalitis. This entity is characterized by the presence of limbic encephalitis, hyponatremia, and faciobrachial dystonic seizures. Herein, we present the case of a male patient with an onset of epileptic seizures (generalized tonic-clonic seizure), and involuntary dystonic movements that affect the right side of his face and right upper limb associated with mental disorder, and affectation of higher functions. The electroencephalogram showed continuous generalized slowing of the background activity. The brain magnetic resonance imaging showed signal hyperintensity at the level of both mesial temporal lobes and hippocampi and in the head of the right caudate nucleus. Anti-thyroglobulin antibodies were positive, and he was initially diagnosed as Hashimoto's encephalopathy (HE). However, the response to corticosteroids was not completed as it is usually observed in HE. For that, antibodies for autoimmune encephalitis were tested, and the anti-LGI1 antibodies were positive in serum and cerebrospinal fluid. HE is an important differential diagnosis to consider. Furthermore, the presence of Anti-thyroglobulin antibodies should not be taken as the definitive diagnostic criteria, since these antibodies could be associated with other autoimmune encephalopathies, which include in addition to anti-LGI1, anti-NMDA and anti-Caspr2.

Brain Magnetic Resonance Imaging Characteristics of Anti-Leucine-Rich Glioma-Inactivated 1 Encephalitis and Their Clinical Relevance: A Single-Center Study in China

Objective: To characterize the magnetic resonance imaging (MRI) features of anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis and explore their clinical relevance.

Methods: Patients with anti-LGI1 encephalitis who underwent MRI at our center were included in this study. Baseline and follow-up MRI characteristics were evaluated, and relationships between lesion location and clinical symptoms were analyzed. The extent of signal abnormalities within the lesion overlap region was measured and correlated with modified Rankin Scale scores and serum antibody titer.

Results: Seventy-six patients were enrolled, of which 57 (75%) were classified as MR positive. Brain lesions were located in medial temporal lobe (MTL) (89%) and basal ganglia (BG) (28%). Hippocampus and amygdala were lesion hubs with more than 50% lesion overlap. BG lesions were found in 30% of patients with faciobrachial dystonic seizure (FBDS) and only 7% of patients without FBDS (p = 0.013). Meanwhile, MTL lesions were more commonly observed in patients with memory impairment (70 vs. 0%, p = 0.017). MRI features included hyperintensity and edema at baseline, as well as hypointensity and atrophy at follow-up. Correlations between signal intensity of lesion hubs (including hippocampus and amygdala) and modified Rankin Scale scores were found on T2 (r = 0.414, p < 0.001) and diffusion-weighted imaging (r = 0.456, p < 0.001).

Conclusion: MTL and BG are two important structures affected by anti-LGI1 encephalitis, and they are associated with distinctive symptoms. Our study provided evidence from Chinese patients that BG lesions are more commonly observed in patients with FBDS, potentially suggesting BG localization. Furthermore, in addition to supporting diagnosis, MRI has the potential to quantify disease severity.

Anti-leucine-rich Glioma Inactivated-1 Encephalitis Associated with Essential Thrombocythemia

Anti-leucine-rich glioma inactivated-1 (anti-LGI1) encephalitis is a subgroup of autoimmune encephalitis. We herein report the case of a 60-year-old man who presented with typical symptoms, including short-term memory loss, mental abnormalities, hyponatremia and seizures characterized by faciobrachial dystonic seizures and who was diagnosed with anti-LGI1 encephalitis. At the same time, he was diagnosed with essential thrombocythemia. A significant improvement was obtained by treatment with corticosteroid, immunoglobulin, mycophenolate mofetil, and hydroxyurea. Autoimmune diseases are associated with a significantly increased risk of developing myeloproliferative neoplasms, which may explain the coexistence of anti-LGI1 encephalitis and essential thrombocythema in this patient; however, but more cases and studies are needed to determine whether there is any correlation between these conditions.

Clinical features of patients with anti-leucine-rich glioma inactivated-1 protein associated encephalitis: a Chinese case series

Purpose: Antibodies against leucine-rich glioma inactivated 1 (LGI1) are associated with limbic encephalitis and faciobrachial dystonic seizures (FBDS). We present a large series of Han Chinese patients for further clinical refinement. Materials and methods: Serum and cerebrospinal fluid samples from patients were tested. Clinical information of patients with serum anti‑LGI1antibody positivity was retrospectively reviewed, and descriptive statistical analysis was performed. Results: The median onset age of the 24 patients was 56.9 years. Among these cases, 18 (75%) patients presented with new‑onset refractory seizures, 18 (75%) patients had memory deficits, eight (33.3%) patients had a personality changes and five (20.8%) patients had a disturbance of consciousness. FBDS was observed in nine (37.5%) patients and five of them presented with FBDS as the initial symptom. No cancer was detected in any patient by CT scans. Fourteen (58.3%) patients had hyponatremia. Lymphocytic pleocytosis and protein concentration elevation in CSF were detected in four (16.7%) and six (25%) patients, respectively. Twelve (50%) patients showed paroxysmal sharp/spike waves and slow waves on EEG and seven (29.2%) patients showed mesial temporal region abnormalities by MRI scans. All patients received antiepileptic drugs and immunotherapy. After treatments, the modified Rankin scores of all patients were decreased. Conclusions: Our study showed that Han Chinese patients with anti‑LGI1 antibody associated encephalitis had prominent clinical manifestations including seizures, memory deficits and FBDS. They showed neurological improvement with timely immunotherapy. Prompt treatments after rapid clinical recognition is important to improve the prognosis of patients.

Clinical features of limbic encephalitis with LGI1 antibody

OBJECTIVE

The objective of this study was to analyze the clinical manifestation, course, evolution, image manifestation, and treatments of LGI1 limbic encephalitis (LE).

PATIENTS AND METHODS

Studies confirmed that LE with the complex antibody of voltage-gated potassium channels is LGI1 LE. Since then, LE cases have been reported. In this study, 10 typical LE cases were searched in PubMed. These cases and one additional case, which we reported herein, were retrospectively analyzed.

RESULTS

All the patients suffered from recent memory deterioration. The following cases were observed: eight with faciobrachial dystonic seizures (FBDS), six with different kinds of epileptic seizures (four complex partial seizures, one myoclonus seizure, and one generalized tonic-clonic seizure), four with FBDS and different kinds of epileptic seizures at the same time, five with mental disorders (one visual hallucination, one paranoia, one depression, one anxiety, and one dysphoria), five with hyponatremia, and two with sleep disorder. The brain MRI of nine patients revealed abnormalities in the mediotemporal lobe and the hippocampus. The LGI1 antibodies in the blood and/or cerebrospinal fluid (CSF) were positive. The content of the CSF protein of two patients increased slightly. The tumor marker of all the patients was normal, but capitate myxoma was detected in the combined pancreas duct of one patient. Gamma globulin and hormone treatments were administered to nine patients. Of these patients, six received a combination of antiepileptic drugs. The clinical symptoms of all the patients improved.

CONCLUSION

LGI1 LE is an autoimmune encephalitis whose clinical manifestations are memory deterioration, FBDS, epileptic seizure, mental disorders, and hyponatremia. Brain MRI shows that this autoimmune disease mainly involves the mediotemporal lobe and the hippocampus. This condition can also be manifested with other autoimmune encephalitis cases but can be rarely associated with tumors. After patients with LGI1 LE receive gamma globulin and hormone treatments, their clinical prognosis is good.