Studies On DST For HPA Axis Function In Different Types Of Patients With TBI

BackgroundTraumatic brain injury (TBI) can cause dysfunction of hypothalamic-pituitary-adrenal axis (HPA) and critical illness-related corticosteroid insufficiency (CIRCI) occur,All within the scope of brain trauma has maintained that it is a fact.Dexamethasone suppression test was used in the majority of Cushing’s disease and Cushing’s syndrome similar HPA axis in patients with lesions in the study. Impaired HPA axis and CIRCI occurs after TBI occurs rarely studied. This study assumes that different damage degree of TBI has different effect on the HPA axis function.ObjectiveBy dexamethasone suppression test (DST) to determine the different degree of injury in patients with acute TBI clinical HPA axis function is impaired and the extent of the damage. Find out the different damage degree of TBI at different time points HPA axis damage degree is different.The patients with TBI in the acute phase of traumatic change situation of cortisol, When the patient implement DST. The inhibition degree of DST to HPA axis in the patients with different degree of TBI, The ratio of DST positive and negative. In order to clear the different damage levels in patients with TBI HPA axis function and the occurrence of adverse stress. Critical illness related to TBI cortisol deficiency (CIRCI) in patients were diagnosed early and Glucocorticoid replacement therapy for patients provide a theoretical basis.MethodA consecutive series of48patients with TBI were enrolled in this study from Ordos Central Hospital and Tianjin Medical University General Hospital. The sampled population has been followed from September,2011to September,2012and is on admission within24h after TBI. Patients are divided into three groups (mild, moderate and severe) according to GCS score. During the first day after admission, we collected blood sample of all48patient to determine the concentration of cortisol. Then at7:00am in the day3,4,5after admission, blood sample was also collected from11,23,14patients respectively for concentration determination of cortisol and Dexamethasone (1.5mg) was taken orally at24:00pm on the same day. After that, the concentration of cortisol was determined again at7:00am on the following day. When Some patients was discharged, another detection was needed. In this research, we measured cortisol concentration by the method of enzyme amplified chemiluminescence immunoassay. All data presented as the mean plus or minus SD. One-way ANOVA was applied to assay different cortisol level among mild, moderate and severe TBI patients. Chi-square test was used to analyze the difference of the result of DST. All analyses were carried out in SPSS for Windows version18.0(SPSS Inc, Chicago,Ill), and P<0.05was considered as statistically significant.Result(1)48cases of mild, moderate and severe TBI patients within24hours of admission serum cortisol concentrations of46patients with different degrees of increase, accounting for95.83%. Serum cortisol decrease observed in2patients, accounted for4.17%.(2)48cases of different degree of TBI patients with serum cortisol concentrations were measured in3to5days after injury (72to120hours),37cases (77.08%) decreased to the normal range,11cases (22.92%) is still higher than normal.(3)48TBI patients were randomly divided into three groups according to the detection time (3rd day after11cases of patients with injuries;4th day,23;5th day in14cases) of Dexamethasone suppression experiments, but no difference was found among the three groups (x2=1.705, P>0.05). Indicate different damage degree of TBI patients in3～5days after the injury the midnight24point dexamethasone suppression test there was no difference.(4) Through the48cases of mild, moderate and severe TBI patients dexamethasone suppression test before and after comparison of serum cortisol concentrations.In dexamethasone suppression test (DST), the positive rate of DST in three (mild, medium, severe) TBI groups was89.47%,40.0%and36.84%and the negative rate was10.53%,60.0%,63.15%respectively. The number of patients in each group (mild, medium, severe) was19,10,19. Conclusion(1) TBI as a strong source of stress, can cause rapid activation of the hypothalamus-pituitary-adrenal axis which could regulate the stress response. According to the degree of injury increases, the stress increases gradually also significantly elevated cortisol. According to the degree of injury increases, the stress increases gradually also significantly elevated cortisol. A handful of TBI patients may be due to the damage of HPA axis can appear low cortisol levels within24hours(2) Different damage degree TBI patients most3-5days (72-120hours) after injury within the first stress reaction leads to increase of serum cortisol can drop to normal levels.(3) There was no significant difference for dexamethasone suppression test to different damage degree of TBI patients in the midnight24point on3-5days after the injury.Show3to5days after TBI can be used as the time window of the dexamethasone suppression test for detection of HPA axis dysfunction(4) Injury of patients with TBI is heavier, the greater the likelihood of HPA axis dysfunction occurred, the damage degree of HPA may also is heavier,Dexamethasone suppression effect is worse to HAP axis. Dexamethasone suppression strength (dexamethasone suppression ratio) and injury severity of TBI was Negative correlation, Dexamethasone suppression strength (dexamethasone suppression ratio) is lower, TBI injury is more severe, the greater the likelihood of occurrence of stress bad, the worse the prognosis.