The Association Between SCR And Psychiatric Symptoms In Anti-N-methyl-D-aspartate Receptor Encephalitis

Background:Anti-N-methyl-D-aspartate receptor(NMDAR)encephalitis is the second most common autoimmune encephalitis characterized by prominent neuropsychiatric symptoms.Patients show different clinical symptoms according to the stage of the disorder,after flu-like prodrome,patients present psychiatric symptom such as agitation psychosis and mood changes within 2 weeks,then the majority of cases will progress neurologic complication like seizures,movement disorder or central hypoventilation.Over 70%of cases with anti-NMDAR encephalitis have psychiatric symptoms,usually at illness onset.In clinical practice,psychiatric symptoms play important role in diagnosis of anti-NMDAR encephalitis.Serum creatinine is a product of creatine and phosphocreatine metabolism,which produced by nonenzymatic chemical dehydration of creatine,and the creatinine level reflects creatine pool directly the creatine-phosphocreatine-creatinine system is described as an efficient energy buffering system which quickly replenishes ATP to maintain energy stable levels when tissues need a large quantity of energy demands suddenly,especially in brain and muscles.As a natural compound of energy homeostasis,creatine/creatinine system plays in brain function and development.Creatine as well as creatinine does not only involve in neuronal growth and axonal elongation,but also ameliorates oxidative,glutamatergic excitotoxicity and apoptosis,both in vitro and in vivo.Because of these properties,several studies have emphasized the neuroprotective effect of brain-related disorders,such as amyotrophic lateral sclerosis(ALS),Huntington’s disease and Parkinson’s Disease.several studies implicate Impairments in brain energy metabolism may be one of the leadinghypotheses in pathogenesis of psychiatric disorders.The ability of creatine supplement is opening up the exciting possibility to provide a novel,natural way for the treatment of psychiatric disease.Objective:In this study,we investigated the relationship between SCR levels and the incidence of psychiatric symptoms in patients with anti-N-methyl-D-aspartate receptor(anti-NMDAR)encephalitis.We try to assess whether higher SCR plays protective role for anti-NMDAR encephalitis with psychiatric symptomsMethods:The SCR levels were tested in 69 patients with anti-NMDAR encephalitis at admission.Clinical data,such as demographics,clinical manifestations were got from medical records by two neurologists.Blood samples were collected from patients in the first morning at admission before any corticosteroids and immunosuppressive treatments.Clinical characteristics and blood and CSF parameters were compared between the group of patients with psychiatric symptoms(P+group)and the group of those without psychiatric symptoms(P-group).We compared to psychiatric symptom incidence among different subgroups according to the SCR level.What’s more,all patients,female subgroup and male subgroup were divided into three group according to SCR value tercile.The association between the SCR levels and psychiatric symptoms was analyzed by multivariate logistic regression analyses and Kendall’s tau-b correlation coefficient.Results:1.Among all study participants,the SCR levels in the P+group were significantly lower than those in the P-group(P<0.001).2.In the female subgroup,the SCR levels in the P+group were significantly lower compared to the P-group(P<0.001),whereas in the male subgroup,the SCR levels did not differ between the two groups(P=0.084).3.Furthermore,the highest SCR tercile overall had a significantly lower incidence of psychiatric symptoms than the lowest tercile for the full sample(P<0.001)and female subgroup(P=0.005),The percentage of psychiatric symptoms showed a gradual decline when the SCR tercile increased in female patients,but there was no significant difference in male patients(P=0.656).4.A significant negative correlation between the SCR levels and the occurrence of psychiatric symptoms was observed in all patients(r=-0.392,P<0.001)and female subgroup(r=0.461,P=0.001),while no significant correlation was found in male patients(r=0.271,P=0.084).5.Multivariate logistic regression analysis showed that the association was independent after adjusting for age,cystatin C and the modified Rankin Scale(mRS)score(P=0.001).A similar result was found in the female subgroup(P=0.010),but not in the male subgroup(P=0.225).Conclusions:Our study indicated that the SCR level was negatively correlated with incidence of psychiatric symptoms in female patients.Higher SCR level could be a protective factor for psychiatric symptoms in female patients with anti-NMDAR encephalitis.