title: Permanent hypopituitarism is rare after structural traumatic brain injury in early childhood.
abstract: BACKGROUND
  We sought to determine the incidence of permanent hypopituitarism in a potentially high-risk group: young children after structural traumatic brain injury (TBI).
  
  
  METHODS
  We conducted a cross-sectional study with longitudinal follow-up. Dynamic tests of pituitary function (GH and ACTH) were performed in all subjects and potential abnormalities critically evaluated. Puberty was clinically staged; baseline thyroid function, prolactin, IGF-I, serum sodium, and osmolality were compared with age-matched data. Diagnosis of GH deficiency was based on an integrated assessment of stimulated GH peak (<5 μg/liter suggestive of deficiency), IGF-I, and growth pattern. ACTH deficiency was diagnosed based on a subnormal response to two serial Synacthen tests (peak cortisol <500 nmol/liter) and a metyrapone test.
  
  
  RESULTS
  We studied 198 survivors of structural TBI sustained in early childhood (112 male, age at injury 1.7 ± 1.5 yr) 6.5 ± 3.2 yr after injury. Sixty-four of the injuries (33%) were inflicted and 134 (68%) accidental. Two participants had developed precocious puberty, which is within the expected background population rate. Peak stimulated GH was subnormal in 16 participants (8%), in the context of normal IGF-I and normal growth. Stimulated peak cortisol was low in 17 (8%), but all had normal ACTH function on follow-up. One participant had a transient low serum T(4). Therefore, no cases of hypopituitarism were recorded.
  
  
  CONCLUSIONS
  Permanent hypopituitarism is rare after both inflicted and accidental structural TBI in early childhood. Precocious puberty was the only pituitary hormone abnormality found, but the prevalence did not exceed that of the normal population.
authors.affiliation: Liggins Institute, University of Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: Natasha L
authors.initials: NL
authors.lastname: Heather
authors.forename: Craig
authors.initials: C
authors.lastname: Jefferies
authors.forename: Paul L
authors.initials: PL
authors.lastname: Hofman
authors.forename: José G B
authors.initials: JG
authors.lastname: Derraik
authors.forename: Christine
authors.initials: C
authors.lastname: Brennan
authors.forename: Patrick
authors.initials: P
authors.lastname: Kelly
authors.forename: James K M
authors.initials: JK
authors.lastname: Hamill
authors.forename: Rhys G
authors.initials: RG
authors.lastname: Jones
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Rowe
authors.forename: Wayne S
authors.initials: WS
authors.lastname: Cutfield
mesh_terms: D017668:Age of Onset; D001930:Brain Injuries / Q000150:complications* / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007018:Hypopituitarism / Q000453:epidemiology / Q000209:etiology*; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D015995:Prevalence