Abstract: Objective  To analyze the risk factors on paroxysmal sympathetic hyperactivity(PSH) after moderate or severe traumatic brain injury (TBI) and its impact on prognosis.  Methods  The subjects were patients with moderate or severe  TBI treated in the hospital . The demographic information and clinical information were collected. The subjects were divided into two groups， PSH group (n=27) and control group (n=99) according to whether being diagnosed as PSH. The risk factors of PSH and its impact on prognosis of TBI were analyzed by logistic regression. Hospital stay time， ICU time，Glasgow Outcome Scale(GOS)  were analyzed.Results  In 126 subjects (male n=82; female n=44)， 27 subjects were diagnosed as PSH(21.4%). The potential risk factors of PSH included systolic blood pressure >140 mmHg at admission (OR=3.21，95%CI=1.317.87， P=0.011)，GCS score<8 (OR=4.34， 95%CI=1.7310.93， P=0.002)， with cerebral contusion and laceration(OR=4.29，95%CI=2.558.26，P<0.001)， the volume of intracranial hemorrhage  ≥50  ml (OR=2.33，95%CI=1.425.13， P=0.003）   and with hydrocephalus (OR=3.57， 95%CI=1.369.37， P=0.010).  Moreover， PSH was associated with protracted hospital stays (OR=5.21，95%CI=2.887.42， P=0.002)   and lower GOS  (OR=1.75，95%CI=1.243.78， P=0.009). Conclusion  PSH is a common complication in patients after moderate or severe  TBI. The risk factors of PSH included higher systolic blood pressure >140 mmHg at admission， lower GCS score， with brain contusion and with hydrocephalus. The patients with PSH after moderate or severe  TBI may stay more days in hospital and have bad prognosis.

Key words: traumatic brain injury, paroxysmal sympathetic hyperactivity, risk factors, prognosis