A Prognostic Analysis of the Outcomes in Patients With Anti-γ-Aminobutyric Acid B Receptor Encephalitis

Outcome and Sequelae of Autoimmune Encephalitis

Autoimmune etiologies are a common cause for encephalitis. The clinical syndromes consistent with autoimmune encephalitis are both distinct and increasingly recognized, but less is known about persisting sequelae or outcomes. We searched PubMed for reports on outcomes after autoimmune encephalitis. Studies assessing validated, quantitative outcomes were included. We performed a narrative review of the published literature of outcomes after autoimmune encephalitis. We found 146 studies that produced outcomes data. The mortality rates were 6%-19% and the relapse risks were 10%-62%. Most patients achieved a good outcome based on a score on the modified Rankin Scale (mRS) of ≤2. Forty-nine studies evaluated outcomes beyond mRS; these studies investigated cognitive outcome, psychiatric sequelae, neurological deficits, global function, and quality-of-life/patient-reported outcomes using various tools at varying time points after the index hospital discharge. These more-detailed assessments revealed that most patients had persistent impairments, with frequent deficits in cognitive function, especially memory and attention. Depression and anxiety were also common. Many of these sequelae continued to improve over months or even years after the acute illness. While we found that lasting impairments were common among survivors of autoimmune encephalitis, additional research is needed to better understand the nature and impact of these sequelae. Standardized evaluation protocols are needed to improve the ability to compare outcomes across studies, guide rehabilitation strategies, and inform outcomes of interest in treatment trials as the field advances.

Enhancing the clinical diagnosis of the acute and subacute phases of autoimmune encephalitis and predicting the risk factors: the potential advantages of 18F-FDG PET/CT

BACKGROUND

2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography (18F-FDG PET) could help evaluate metabolic abnormalities by semi-quantitative measurement to identify autoimmune encephalitis (AE). Few studies have been conducted to analyze the prognostic factors of AE. The study aimed to explore the values of diagnosis and treatment evaluation by 18F-FDG PET and preliminarily discussed the potential value in predicting the prognosis of AE patients.

METHODS

AE patients underwent 18F-FDG PET/CT and magnetic resonance imaging (MRI). There were two steps to analyse 18F-FDG PET imaging data. The first step was visual assessment. The second step was to analyse 18F-FDG PET parameters using Scenium software (Siemens Molecular Imaging Ltd). The mean standardized uptake value (SUVmean) and maximum standardized uptake value (SUVmax) of brain relative regional metabolism (BRRM) were quantified in the case and control groups according to the anatomical automatic labeling (AAL) partition. The main statistical method was the Kruskal-Wallis test. Finally, the simple linear regression method was used to analyse the relationships between 18F-FDG PET parameters and the modified Rankin Scale (mRS) scores before and after treatment.

RESULTS

The results on 18F-FDG PET showed that visual assessment abnormalities were in the mesial temporal lobe (MTL) (70.8%), (mainly infringing on the hippocampus and amygdala), basal ganglia (62.5%), frontal lobes (37.5%), occipital lobes (29.2%), and parietal lobes (12.5%). The positive rate of abnormalities on 18F-FDG PET was more sensitive than that on MRI (95.5% vs 32.2%, p = 0.001). The number of lesions on PET was positively correlated with the mRS scores before and after treatment, and the correlation before treatment was more significant. Before treatment, the SUVmean of the left occipital lobe was the most remarkable (SUVmean, R2 = 0.082, p > 0.05) factor associated with the mRS score, and the correlation was negative. With regard to prognosis, the SUVmax of the MTL was the most notable (R2 = 0.1471, p > 0.05) factor associated with the mRS score after treatment, and the correlation was positive.

CONCLUSIONS

18F-FDG PET could be more sensitive and informative than MRI in the early phases of AE. The common pattern of AE was high MTL metabolism on 18F-FDG PET, which was associated with hypometabolism of the occipital lobe, and the number of lesions on PET before treatment may be significant factors in assessing disease severity. The SUVmax of MTL hypermetabolism may serve as a prognostic biomarker in AE.

Assessment of disease severity and patient prognosis in anti-GABABR encephalitis with and without comorbid tumors

Purpose

This study aimed to analyze the severity of the condition and prognosis of patients with anti-gamma-aminobutyric-acid type B receptor (anti-GABA_BR) encephalitis with tumors.

Methods

Patients with anti-GABA_BR encephalitis admitted to one of two hospitals from 2020 to 2022 were enrolled and divided into tumor and non-tumor groups. The clinical characteristics, condition severity, treatment options, and prognosis of the two groups of patients were compared and analyzed.

Results

Eighteen patients with anti-GABA_BR encephalitis were included, ten of whom had tumors. The comparison of clinical characteristics showed that rates of status epilepticus and coma were significantly higher in the group with tumors (P = 0.013 and P = 0.025, respectively); the incidences of pulmonary infection, respiratory failure, hyponatremia, and hypoproteinemia were also substantially more frequent in the tumor group (P = 0.054, P = 0.036, P = 0.015, and P = 0.025, respectively). The laboratory test result comparison showed that serum neuron-specific enolase (NSE) and carcinoembryonic antigen (CEA) were present only in the group with tumors (P = 0.036 and P = 0.092, respectively), but there was no significant difference in the occurrence of elevated CEA between the two groups. Conversely, the percentage of serum systemic autoimmune antibodies was higher in the group without tumors than in the group with tumors (P = 0.043). Patients with tumors tended to have poor outcomes (P = 0.152, OR: 7.000).

Conclusion

Severe brain damage and complications occur in patients with anti-GABA_BR encephalitis and comorbid tumors. Early screening for serum NSE and CEA helps in the early diagnosis and treatment of tumors. The prognosis is much worse for anti-GABA_BR encephalitis with tumors.

Long-term efficacy and safety of different corticosteroid courses plus mycophenolate mofetil for autoimmune encephalitis with neuronal surface antibodies without tumor

Objective

To compare the efficacy and safety of different-course corticosteroids plus mycophenolate mofetil (MMF) as maintenance therapy in autoimmune encephalitis (AE) with neuronal surface antibodies (NSAbs) without tumor and explore the optimal course of corticosteroids.

Methods

Fifty-five patients with definite AE without tumor were enrolled consecutively between June 2015 and November 2020 and retrospectively divided three groups according to the course of treatment with corticosteroid, i.e., a group of patients with a course of 3-6 months (Group 3-6mo), 6-12 months (Group 6-12mo), and >12 months (Group >12mo). Demographic data, clinical manifestation and ancillary tests results were recorded. The dosage and courses of corticosteroid treatment, the recovery of neurological function, the occurrence of adverse effects, and relapses were followed up.

Results

A total of 55 patients were included in the final analysis. The numbers of patients in Group 3-6 mo, Group 6-12 mo, and Group >12 mo was 14, 17, and 24, respectively. A significantly higher proportion of patients in Group >12 mo showed a decreased level of consciousness at the onset (12, 50%) than in Group 3-6 mo and Group 6-12 mo (2,14.3%; 3, 17.6%) (p = 0.033). The incidence of MRI abnormalities was significantly higher in Group 6-12 mo and Group >12 mo (10, 58.8%; 16, 66.7%) than in Group 3-6 mo (3, 21.4%) (P=0.023). Ordinal regression analysis indicated that decreased level of consciousness was associated with the course of corticosteroid (OR=3.838, 95% CI: 1.103-13.323, P=0.035). No significant difference was observed between the three groups regarding the cumulative dose of corticosteroids administered during the first three months of long-term treatment (P>0.05). Additionally, no significant difference in the cumulative dosage of corticosteroids was found between patients in Group 6-12 months and Group >12 months during the first 6 months after beginning long-term treatment. The mRS scores of the three groups were not statistically significant before and after first-line treatment or at the last follow-up. Bonferroni multiple comparison test indicated that the mRS scores of patients in Group 6-12 months and Group >12 months were not statistically significant at 3 months and 12 months after the start of long-term treatment. During the follow-up, 50 (90.9%) patients achieved satisfactory neurological function (mRS score ≤2). Five patients (9.1%) experienced a first relapse and 2 of them were overlapped with both anti-NMDA receptor and glial antibodies. The incidence of adverse effects was significantly higher in Group >12 mo (17, 70.8%) than in Group 3-6 mo (3, 21.4%) and Group 6-12 mo (5, 29.4%) (P=0.003).

Conclusions

The beneficial effects of oral corticosteroid treatment may do not persist beyond 12 months and may even contribute to an increased incidence of adverse effects. In order to optimize the effectiveness and safety of treatment, we recommend a corticosteroid course of 3-12 months. Patients with reduced levels of consciousness may be more inclined to choose longer courses of corticosteroids for long-term treatment. Patients with an "overlapping syndrome" may require more intense immunotherapy to prevent relapse.

Clinical characteristics and prognosis of anti-γ-aminobutyric acid-B receptor encephalitis: A single-center, longitudinal study in China

Objective

Anti-γ-aminobutyric acid-B receptor (GABA_BR) encephalitis is a rare type of autoimmune encephalitis. There are only a few, small, published studies regarding prognosis, so prediction of prognosis is of limited accuracy. We identified 37 cases of anti-GABA_BR encephalitis in China. Here, we present these patients' clinical characteristics and long-term outcomes.

Methods

We collected and retrospectively analyzed the clinical data of 37 patients with anti-GABA_BR encephalitis from Beijing Fengtai You'anmen Hospital.

Results

The study cohort comprised 37 patients of anti-GABA_BR encephalitis of median age 61 years (range: 11–77), 28 of whom were male. The main clinical manifestations were epilepsy (91.9%, 34/37), psychiatric disorders (94.6%, 35/37) and cognitive impairment (97.3%, 36/37). Tumors were identified in 18 (48.6%) patients. First-line immunotherapy was administered to 34 patients, 31 of whom (90.6%) responded favorably. During a median follow-up of 18 months (range: 1–72 months), 21 patients had good outcomes [Modified Ranking Scale (mRS ≤2)], 16 (43.2%) died (mRS 6), and 7 (18.9%) relapsed. Age (P = 0.005), disturbance of consciousness (P = 0.018), admission to the Neurology Intensive Care Unit (P = 0.003), mechanical ventilation (P = 0.009), more numerous clinical manifestations (P = 0.008), comorbid malignancy (P = 0.008), multiple anti-neuronal antibodies (P = 0.029), and hyponatremia (P = 0.023) differed significantly between patients with good outcomes (mRS 0–2) and those with poor outcomes (mRS 3–6).

Conclusion

Men aged 50–70 years accounted for most of the patients with anti-GABA_BR encephalitis in our case series. The main clinical manifestations were epilepsy and neuropsychiatric dysfunction. The participants often had concomitant lung cancer, particularly small-cell lung cancer. Patients with lung tumors and/or serious manifestations usually had a poor prognosis with high mortality. Early identification and treatment of tumors improved the poor prognosis to some extent.