title: Acute secondary adrenal insufficiency after traumatic brain injury: a prospective study.
abstract: OBJECTIVE
  To determine the prevalence, time course, clinical characteristics, and effect of adrenal insufficiency (AI) after traumatic brain injury (TBI).
  
  
  METHODS
  Prospective intensive care unit-based cohort study.
  
  
  METHODS
  Three level 1 trauma centers.
  
  
  METHODS
  A total of 80 patients with moderate or severe TBI (Glasgow Coma Scale score, 3-13) and 41 trauma patients without TBI (Injury Severity Score, >15) enrolled between June 2002 and November 2003.
  
  
  METHODS
  Serum cortisol and adrenocorticotropic hormone levels were drawn twice daily for up to 9 days postinjury; AI was defined as two consecutive cortisols of < or =15 microg/dL (25th percentile for extracranial trauma patients) or one cortisol of < 5 microg/dL. Principal outcome measures included: injury characteristics, hemodynamic data, usage of vasopressors, metabolic suppressive agents (high-dose pentobarbital and propofol), etomidate, and AI status.
  
  
  RESULTS
  AI occurred in 42 TBI patients (53%). Adrenocorticotropic hormone levels were lower at the time of AI (median, 18.9 vs. 36.1 pg/mL; p = .0001). Compared with patients without AI, those with AI were younger (p = .01), had higher injury severity (p = .02), had a higher frequency of early ischemic insults (hypotension, hypoxia, severe anemia) (p = .02), and were more likely to have received etomidate (p = .049). Over the acute postinjury period, patients with AI had lower trough mean arterial pressure (p = .001) and greater vasopressor use (p = .047). Mean arterial pressure was lower in the 8 hrs preceding a low (< or =15 microg/dL) cortisol level (p = .003). There was an inverse relationship between cortisol levels and vasopressor use (p = .0005) and between cortisol levels within 24 hrs of injury and etomidate use (p = .002). Use of high-dose propofol and pentobarbital was strongly associated with lower cortisol levels (p < .0001).
  
  
  CONCLUSIONS
  Approximately 50% of patients with moderate or severe TBI have at least transient AI. Younger age, greater injury severity, early ischemic insults, and the use of etomidate and metabolic suppressive agents are associated with AI. Because lower cortisol levels were associated with lower blood pressure and higher vasopressor use, consideration should be given to monitoring cortisol levels in intubated TBI patients, particularly those receiving high-dose pentobarbital or propofol. A randomized trial of stress-dose hydrocortisone in TBI patients with AI is underway.
authors.affiliation: Division of Neurosurgery, UCLA School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA.
authors.forename: Pejman
authors.initials: P
authors.lastname: Cohan
authors.forename: Christina
authors.initials: C
authors.lastname: Wang
authors.forename: David L
authors.initials: DL
authors.lastname: McArthur
authors.forename: Shon W
authors.initials: SW
authors.lastname: Cook
authors.forename: Joshua R
authors.initials: JR
authors.lastname: Dusick
authors.forename: Bob
authors.initials: B
authors.lastname: Armin
authors.forename: Ronald
authors.initials: R
authors.lastname: Swerdloff
authors.forename: Paul
authors.initials: P
authors.lastname: Vespa
authors.forename: Jan Paul
authors.initials: JP
authors.lastname: Muizelaar
authors.forename: Henry Gill
authors.initials: HG
authors.lastname: Cryer
authors.forename: Peter D
authors.initials: PD
authors.lastname: Christenson
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Kelly
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000309:Adrenal Insufficiency / Q000097:blood / Q000453:epidemiology* / Q000209:etiology*; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001930:Brain Injuries / Q000097:blood / Q000150:complications* / Q000503:physiopathology; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010913:Pituitary-Adrenal System / Q000503:physiopathology; D015995:Prevalence; D011446:Prospective Studies; D013997:Time Factors
chemical_list: D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone