Clinical Features And Prognosis Of Two Common Limbic Encephalitis

Background and purposes:Autoimmune encephalitis(AE)generally refers to a class of encephalitis mediated by autoimmune mechanism,with an incidence rate of 6.5/100,000.It is a reversible disease,which can have a good clinical outcome if diagnosed and treated in time.At present,more than 15 subtypes of AE have been described,which produce different specific antibodies against different target antigens.Therefore,the clinical characteristics and the pathogenesis of the disease depend on the different target-specific antibodies.Patients suffering from LE typically show a rapidly progressive encephalitis together with alterations of consciousness,psychotic symptoms,agitation,memory difficulties,involuntary movements,or seizures dependent on the subtype of LE.The most common is the following two anti-neuronal surface antibody encephalitis,leucine-rich glioma inactivation 1 protein(LG11)antibody encephalitis and anti-gamma aminoaminobutyrate acid B(GABAB)encephalitis.These two types of encephalitis account for 30%and 5%of autoimmune encephalitis,respectively.Both of them belong to limbic encephalitis with similar clinical features,but their characteristics are different.In this study,the clinical manifestations,cerebrospinal fluid,head MRI and prognosis characteristics of 41 patients with anti-LGI1 encephalitis and 35 patients with anti-GABABR antibody encephalitis were summarized and statistically compared,so as to compare the similarities and differences between the two kinds of borderline encephalitis,so as to provide reference for its diagnosis and treatment.Methods:We have prospectively collected 41 cases of anti-LGI1 encephalitis and 35 anti-GABABR encephalitis patients from the First Affiliated Hospital of Zhengzhou University,between June 2016 to August 2019.Cerebrospinal fluid(CSF)and serum antibody tests were performed in patients with suspected autoimmune encephalitis.Indirect immunofluorescence staining kit provided by German OMON(FAI12d)was used for detection.The differences regarding age,gender time from onset to diagnosis,first symptoms,clinical features,head magnetic resonance imaging(MRI),cerebrospinal fluid(CSF),electroencephalogram(EEG),tumor correlation and prognosis were compared between these two types of autoimmune encephalitis.The improved Rankin scale(mRS)was used to evaluate the living ability of the patients.Patients with an mRS score of less than 3 were considered to have a good prognosis.Correspondingly,patients with an mRS score greater than 2 were considered to have a poor prognosis.Results:1.General information of two types of limbic encephalitisIn this study,a total of 41 inpatients diagnosed with anti-LGI1 antibody encephalitis and 35 patients with anti-GABABR antibody encephalitis were collected.A total of 41 patients(32 males and 9 females),ranging from 15 to 82 years old(average of 58 years)were positive for anti-LGI1 antibody,Another 35 patients(23 males and 12 females),ranging from 15 to 84 years old(average of 56 years)were positive for anti-GABABR antibody.No significant difference in age and sex was observed between the two types of encephalitis(P>0.05).The average diagnosis time for anti-LGI1 encephalitis was 65 days,while for anti-GABABR encephalitis was 20 days,and the interval between symptom onset to diagnosis was statistically significant(P=0.009).2.Clinical manifestations and auxiliary examinations of two kinds of limbic encephalitisTwenty-nine(70.73%)patients with anti-LGI1 encephalitis and 28(80.00%)patients with anti-GABABR encephalitis had epileptic seizures.Anti-LGI 1 encephalitis and anti-GABABR encephalitis showed memory loss in 26 cases(63.42%)and 26 cases(74.29%),respectively.The difference between the two groups was not statistically significant(P>0.05).There were 21 cases(72.41%)of anti-LGI1 encephalitis and 2 cases(7.14%)of anti-GABABR encephalitis with focal seizure and the difference between them was statistically significant(P<0.001).There were 15 patients(51.72%)with anti-LGIl antibody encephalitis and 27 patients(96.43%)with anti-GABABR antibody encephalitis had generalized tonic-clonic seizure,and the difference between them was statistically significant(P<0.001).There were 22 cases(53.66%)of anti-LGI1 encephalitis and 28 cases(80.00%)of anti-GABABR antibody encephalitis with mental behavior disorder,and the difference between them was statistically significant(P=0.016).9 cases(21.95%)of anti-LGI1 encephalitis and 22 cases(62.86%)of anti-GABABR antibody encephalitis showed disturbance of consciousness,and anti-GABABR encephalitis was more prone to disturbance of consciousness(P<0.001).Eleven cases(26.83%)of anti-LGI1 encephalitis and 18 cases(51.43%)of anti-GABABR antibody encephalitis had sleep disorders,respectively,and the comparison between them was statistically significant(P=0.028).There were 15 patients(36.59%)with anti-LGI1 encephalitis and 3 patients(8.57%)with anti-GABABR antibody encephalitis with hyponatremia,respectively,and the comparison between them was statistically significant(P=0.004).Only 18 patients(43.90%)with anti-LGI1 encephalitis had FBDS onset.CSF white blood cell count was increased in 5 patients with anti-LGI1 antibody encephalitis,and in 23 patients with anti-GABABR antibody encephalitis,the difference between the two was statistically significant(P<0.001).The proportion of CSF lymphocytes increased in 10 patients with anti-LGI1 antibody encephalitis and in 25 patients with anti-GABABR antibody encephalitis.The difference between the two was statistically significant(P<0.001).The head MRI of 11 patients with anti-LGI1 encephalitis showed abnormal signal,including 4 patients with abnormal signal in basal ganglia region.Corresp ondently,the head MRI of 14 patients with anti-GABABR encephalitis showed abnormal signal.And there was no statistical significance in the two types of encephalitis(P>0.05).Five patients(12.82%)with anti-LGI1 encephalitis showed abnormal signals located in the temporal lobe and hippocampus.In the anti-GABAR encephalitis group,13 cases(38.24%)were found.The difference between the two was statistically significant(P=0.038).3.Tumor and prognosis of two kinds of limbic encephalitisNo patients with anti-LGI1 encephalitis were found to be complicated with tumor.Fourteen cases of anti-GABABR antibody encephalitis were found to have lung mass,of which 7 cases were found to have small cell lung cancer by pathological biopsy,and the rest were found to have lung cancer by chest CT.The follow-up results showed that 34 patients with anti-LGI1 antibody encephalitis and 15 patients with anti-GABABR antibody encephalitis had good prognosis,and the difference between the two was statistically significant(P<0.001).Patients with anti-LGI1 antibody encephalitis had good prognosis.After an average follow-up of 11 months,14 patients of anti-GABABR antibody encephalitis and 2 patients of anti-LGI1 encephalitis died.The difference between the two was statistically significant(P<0.001).Survival analysis showed that patients with anti-GABABR encephalitis with tumors had a lower survival rate than those without tumors(P=0.004).Patients admitted to the ICU with anti-GABABR encephalitis had a lower survival rate than patients not admitted to the ICU(P=0.004).Conclusions:1.Compared with anti-LGI1 encephalitis,the diagnosis time of anti-GABABR encephalitis is shorter,and the clinical symptoms of mental behavior abnormality,consciousness disorder and sleep disorder are more prominent.Tonic clonic seizures are more common in anti-GABABR antibody encephalitis.2.The CSF inflammatory response of anti-GABABR encephalitis was more severe than that of anti-LGI1 encephalitis.Anti-GABABR encephalitis was more likely to have abnormal signals in temporal lobe and hippocampus than anti-LGI1 encephalitis.It is more likely to be complicated with small cell lung cancer.3.Anti-LGI1 encephalitis is more prone to focal seizure than anti-GABABR encephalitis,which is characterized by FBDS and hyponatremia.Abnormal signs of head MRI were located in the temporal lobe and hippocampus,but also prone to involve the basal ganglia at the same time.4.The prognosis of anti-GABABR encephalitis is worse than that of anti-LGI1 encephalitis.Tumor presence and ICU admission are risk factors for survival of patients with anti-GABABR encephalitis.