title: Low Tri-Iodothyronine Syndrome in Neurosurgical Patients: A Systematic Review of Literature.
abstract: BACKGROUND
  Intracranial neurosurgical disorders are important causes of mortality and disability worldwide. Low tri-iodothyronine (T3) syndrome is a common complication in critically ill patients and is associated with a poor prognosis.
  
  
  METHODS
  We performed a systematic review of clinical studies analyzing the prevalence of low T3 syndrome and the association of serum T3 concentrations with disease severity and outcomes in patients with traumatic brain injury (TBI), hydrocephalus, aneurysmal subarachnoid hemorrhage (SAH), and brain tumors.
  
  
  RESULTS
  The greatest prevalence rate of low T3 syndrome was reported in severe TBI patients (up to 67%), followed by patients with brain tumors (54%), aneurysmal SAH (up to 43%), and hydrocephalus (33%). A lower than normal serum T3 concentration was associated with greater disease severity, worse health status, complicated clinical course, and worse hospital discharge outcomes for TBI, aneurysmal SAH, and brain tumor patients. Lower T3 concentrations were also associated with greater long-term mortality and increased disability in TBI and aneurysmal SAH patients.
  
  
  CONCLUSIONS
  Low T3 syndrome is a common complication in patients suffering from intracranial neurosurgical disorders and is associated with greater disease severity, complicated clinical course, and greater mortality and handicap rates. However, it remains unclear if low T3 syndrome can impact the findings of currently available clinical prognostic models and if management of low T3 syndrome can improve outcomes in neurosurgical patients.
authors.affiliation: Department of Neurosurgery, Lithuanian University of Health Sciences, Kaunas, Lithuania; Neuroscience Institute, Lithuanian University of Health Sciences, Kaunas, Lithuania. Electronic address: a.bunevicius@yahoo.com.
authors.forename: Adomas
authors.initials: A
authors.lastname: Bunevicius
authors.affiliation: Department of Neurosurgery, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: Timothy
authors.initials: T
authors.lastname: Smith
authors.affiliation: Department of Neurosurgery, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: Edward R
authors.initials: ER
authors.lastname: Laws
mesh_terms: D006801:Humans; D002532:Intracranial Aneurysm / Q000097:blood / Q000601:surgery; D019635:Neurosurgical Procedures / Q000009:adverse effects* / Q000639:trends; D013345:Subarachnoid Hemorrhage / Q000097:blood / Q000601:surgery; D013577:Syndrome; D013959:Thyroid Diseases / Q000097:blood* / Q000175:diagnosis / Q000209:etiology; D014284:Triiodothyronine / Q000097:blood*
chemical_list: D014284:Triiodothyronine
keywords: Brain tumor; Hydrocephalus; Neurosurgery; Subarachnoid hemorrhage; Thyroid; Traumatic brain injury; Tri-iodothyronine