Low TT4 As A Predictor Of Poor Outcomes In Severe Encephalitis

Background:Severe neurological diseases are brain injuries caused by different etiologies,and their outcome varies with different causes.However,there are common features of brain function due to different degrees of damage.To search for biomarkers of the severity of brain injury may predict the outcome of neurologically ill patients.The significance of that the changes of thyroid function parameters in patients with severe neurological disease is unclear.Thyroid hormone,as an important metabolic regulator in the body,may be involved in the regulation and stabilization of the vivo environment under the conditions of neurologically critical patients.The changes seem to be related to the severity of the disease.To study its regularity in different periods of time and characteristics in patients with severe neurological disease,which is possible to find a biomarker that predicts the outcome of the disease.Objective:To explore the regularity of thyroid hormone changes in patients with severe encephalitis in the acute phase and its predictive value for long-term outcome.Method:This study analyzed information from patients with encephalitis who were admitted to the neurological intensive care unit(NICU)of First Affiliated Hospital of Chongqing Medical University from June 2012 to June 2017.The inclusion criteria were as follows:1)encephalitis as defined according to the latest internationally recognized standards as a change in the mental(decrease/change in awareness/level or personality change lasting at least 24 h)with at least three of the following characteristics:fever(body temperature over 38.2? within 72 h before and after the onset of symptoms),seizures(confirmed by clinical symptoms or anEEG,seizure not attributable to preexisting seizure disorder),newly occurring focal neurological deficits,increase in cells in the cerebrospinal fluid(CSF)(white blood cell count greater than 5 cells/mm3),and EEG or neuroimaging consistent with encephalitis changes;2)Patients with severe encephalitis should meet one of the following:frequent status epilepticus;disturbance of consciousness,Glasgow coma scale(GCS)score<8;limb paralysis,mental and behavioral abnormalities;with brainstem symptoms;severe Or sustained increased intracranial pressure;multiple organ damage to failure;3)Acute or subacute onset;4)age greater than 16 years;and 5)meeting the definition of encephalitis with a minimum NICU stay of at least 48 h(to exclude those who had only transient critical care needs).The exclusion criteria were as follows:1)previous thyroid disease and recent history of thyroid hormone replacement history;not undergoing thyroid function tests during hospitalization;2)not undergoing lumbar puncture CSF examination,or incomplete clinical data;3)a brain abscess;4)intracranial infection caused by trauma or surgery;5)a central nervous system disease caused by acquired immune deficiency syndrome(AIDS),including toxoplasmosis,cryptococcal meningitis,and HIV-related encephalopathy;6)encephalopathy secondary to other factors,including sepsis,septicemia,and noninfectious factors such as toxic or metabolic diseases;7)an immunosuppressive state(including those who require chemotherapy or longterm immunosuppressive therapy after organ transplantation or due to cancer)and previous history of immune diseases;and 8)There have been severe chronic systemic underlying diseases such as heart failure,respiratory failure,chronic kidney disease,and liver disease;9)those who had been treated in other hospitals or transferred to our hospital from other hospitals were excluded;and 10)patient lost during follow-up.Another neurologist followed up the patient by telephone or outpatient visits until 6 months after discharge and assessed neurological outcomes according to the modified Rankin Scale(mRS)score as an outcome measure.Patients with mRS<3 was a good outcome group,mRS?3 was a poor outcome group.SPSS 21.0 software was used to analyze univariate patients with good outcome and poor outcome.For statistically significant factors,Logistic multivariate regression analysis was used to investigate risk factors for poor outcome in patients with severe encephalitis.Result:1 A total of 94 patients with severe encephalitis met the inclusion criteria and included in the study during the study period.There were 42 males(44.68%)and 52 females(55.32%)with an average age of 40(26,48)years.The average length of hospital stay for all patients was 21 days(14,34),and the average length of NICU stay was 8 days(5,15).The mean GCS score at admission was 10(8,12),and the mean APACHE II score was 9(6,13).2 Among 94 patients,69 patients(73.40%)had low TT3(total triiodothyronine,TT3),27 patients(28.72%)had low TT4(total thyroxine,TT4),and TT3 and TT4 decreased at 23 patients(24.47%),4 patients(4.26%)had high TT4,17 patients(18.09%)had low FT3(free triiodothyronine,FT3),3 patients(3.19%)had low FT4(free thyroxine,FT4),and 23 patients(24.47%)had high FT4,suggesting that thyroid function changes are very obvious in the acute phase of severe encephalitis.3 The SPSS 21.0 statistical software package was used for the univariate statistical analysis that showed TT4(P=0.012),FT3(P=0.049)were significantly different between the good-outcome group and the poor-outcome group.4 Logistic regression analysis suggested that low TT4(OR 0.303,95%CI 0.100-0.923,P=0.036)was risk factor for poor outcome of severe encephalitis.5 Compared with the traditional low GCS scores for predicting the poor outcome of severe encephalitis,the brain injury of severe encephalitis patients with reduced TT4 from the perspective of clinical behaviors is more serious and the outcome is worse.Supporting the scientific value of low TT4 for predicting the poor outcome of severe encephalitis.Conclusion:Abnormal thyroid function parameters may be related to self-protection,and its changes suggest that it has predictive value for poor outcome of severe encephalitis.